Norton Triumph Commando 850 motorcycle Workshop manual

 Fes. WORKSHOP
“Ji MANUAL
for
ELECTRIC START
MARK 3
motorcycles
FROM 1975
INTERSTATE
ROADSTER
HI-RIDER (USA. and Canada only)
INTERPOL
MODELS 850:
Commencing at Engine No. 325001 — Frame No. F125001
Published by: . © Copyright 1975
NORTON TRIUMPH INTERNATIONAL LIMITED
KITTS GREEN - BIRMINGHAM B33. OLF - ENGLAND
TELEPHONE: BIRMINGHAM 021-784.5151 TELEX: 339478
Publication No. 00-4224
~~ *
q
Dem \
FOREWORD
The purpose of this manual is to provide the necessary technical instructions to enable distributor
and dealer staff, and also enthusiastic private owners, to carry out all routine maintenance, running
repairs and major overhaul operations.
To provide the clearest possible technical information, and in view of the major improvements
and mandatory design changes introduced on the latest 860 Commando, it has been decided to
omit all earlier versions and devote this manual solely to the Electric-Start, Left-foot-shift 1975
Mark IH model.
Mark II! Commencing Engine No. 325001.
Frame No. F. 125001. .
For earlier models refer to previous publications issued.
From 1970 Part No. 065146.
Separate sections of the manual cover major areas and, where necessary, cross references are
used to facilitate step by step dismantling and re-assembly. The manual is well provided with line
illustrations for clarity and care has been taken to ensure that each illustration fulfils a useful
purpose rather than merely increasing manual content.
Where special service tools are necessary, they are referred to by part number in the text. An
illustrated service tools catalogue is available covering special tools common to previous 850
models. New tools will be catalogued as soon as possible, and page size and piercing will be as
before, allowing inclusion in the master binder in due course.
A fully illustrated parts list and Rider's Manual are available, and will further assist service
operations. Publication Numbers 00-5756 and 066240 respectively
To ensure repair to the same standards as used for 8 new Commando, it is essential to use only
genuine Norton spares available through the normal spares supply system. The main distributors for
the various markets of the world are given below:
EUROPE: Norton Triumph Europe Limited,
North Way,
Walworth, Andover,
Hampshire,
Telephone: Andover (0264) 61414
+ NE
La
U.S.A.
CANADA:
AUSTRALASIA,
NEW ZEALAND,
FAR EAST:
SOUTH AFRICA:
West of Mississippi River:
Norton Triumph Corporation,
6765 Paramount Boulevard,
North Long Beach,
California 90805.
Telephone: (213) 531-7138.
East of Mississippi River:
Berliner Motor Corporation,
Railroad Street and Plant Road
Hasbrouck Heights,
New Jersey 07604.
Telephone: (201) 288-9696.
CANADA
Norton Triumph Canada Limited.
9001 Salley Street,
La Salle,
Province of Quebec.
Telephone: (514) 363-7066.
Norton Triumph Motorcycles Pty. Ltd.,
25 Moxon Road,
Punchbowl,
New South Wales, 2196.
Telephone : Punchbowl 02700731.
Jack's Motors (Pty.) Ltd.
115 Main Street, |
Johannesburg.
Telephone: Johannesburg 217.021.
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CONTENTS
INDEX
TECHNICAL DATA
CONVERSION TABLES
ENGINE/PRIMARY DRIVE
GEARBOX ..
CARBURETOR
FRAME AND ANCILLARIES
FORKS/STEERING HEAD BEARINGS
BRAKES, WHEELS AND TYRES
ELECTRICAL
ROUTINE MAINTENANCE
OVERLEAF
SECTION A
SECTION B
SECTION C
SECTION D
SECTION E
SECTION F
SECTION G
SECTION H
SECTION J
SECTION K
Each section is laid out generally in order of disassembly and assembly ; however, use the following
index to locate any particular subject.
ENGINE
Engine “Top End"
Removing Cylinder Head
Servicing Cylinder Head..
Refitting Cylinder Head ..
Removing Cylinder and Pistons
Servicing Cylinder and Pistons. .
Refitting Pistons and Cylinder ..
Engine “Bottom End”
Removing Crankcase Assembly from Frame...
Dismantling the Crankcase
Crankcase Overhaul ..
Reassembly of Crankshaft to Crankcases
Reassembly of Crankcase Assembly to Frame
Removing Connecting Rods
Refitting Connecting Rods
Crankshaft Servicing
Engine Accessory Systems
Lubrication ..
Oil Pump
Servicing other Lubrication Components
Starter Gear Train & Mechanism
Timing
Timing Cover
Assembly of Timing Side of Engine
Tachometer .. ..
Ignition (Also see “Electrical”, Section J)
Ignition Timing
Auto Advance and Contact Breaker
Engine Complete
Removing and Refitting Engine Complete
PRIMARY TRANSMISSION
Removing Primary Chaincase ..
Dismantling Primary Transmission and Clutch
Assembling Primary Transmission
Clutch Operating Assembly
Chains .. ..
: Section
C1
C2-C8, C10
C9
C11
C12
C33
C15
C16
C17
C29
C32
C18
C28
C19, C20, C27
C21
C24, C25
C22, C23
C37
C26, C31
C30
C36
C39
C40, C41
C38
C13
C14
C34
C35
C42
GEARBOX
Description В ‚| В В В В … … … D1
Gearbox Dismantling .. . .. .. .. i. .. D2-D5
Inspection of Gearbox Parts —.. … … … Ш … .. D6
Assembly of Gearbox .. г. .. .. г. .. .. .. D9, D10, D12
Servicing Gearbox Outer Cover .. .. .. .. № .. D11
Changing Countershaft Sprocket .. .. .. .. .. .. D8
Removing Gearbox from Motorcycle .. .. .. .. .. D7
CARBURETOR AND AIR FILTER
Description .. .. г. .. .. .. … .. |. El
Removal and Disassembly of Carburetors .. . .. .. .. E?, E3
Examination and Reassembly .. .. .. .. |. .. E4, ES
Carburetor Adjustment .. . .. .. .. . . В E7, E9
Fuel Taps . .. .. .. .. …. . . . E6
Air Filter … |. . … … … . .. ‚| E10
FRAME
Removal and Refitting of Power Unit Complete .. |. … … Fi, FA
Frame Checking Dimensions .. .. .. .. FS
Servicing Suspension Units (Shocks) - .. |, … |. … F5, F7
Servicing Swinging Arm .. г. .. |. .. .. .. F8
Removing and Replacing Fuel Tank .. .. .. .. .. .. F9
Removing and Replacing Oil Tank .. |. . |. . .. F10
Accessory and Side Covers .. … … Ш … … … F11
Servicing Isolastic Mounting Assembly … … … . … F2, F12-F16
Rear Fender | .. … .. … .. .. Co F17
Exhaust Systems .. …. .. Co .. № .. .. F18
FORKS
Description. . |. ae . .. . .. .. G1, G2
Removing and Dismantling Forks — .. .. |. … … .. G3, G4
Servicing Steering Head Bearings — .. … № .. .. .. G6, G7
Refitting Front Forks .. .. .. .. .. .. .. .. G8
vn
EN
BRAKES WHEELS AND TIRES
Removing and Dismantling Rear Wheel
Reassembling and Refitting Rear Wheel
Servicing Disc Front Wheel
Disc Brakes: Function
Front Brake Hydraulic Operation
Norton Lockheed Disc Brake
Rear Brake Pedal Adjustment
Tires
ELECTRICAL
Description
Charging System
Alternator
Rectifier
Zener Diode
Battery and Fused Lead
Warning Light and Assimilator
Master Switch
Testing Ignition System
Coils, Capacitors (Condensers), Ballast Resistor
Contact Breaker and Auto Advance
Spark Plugs
Lighting System
Head and Tail Lamps Stop Switches
Handlebar Switch Clusters
Power Take-off Socket
Flashing Direction Indicators
Alternating Horn Set (Police)
Horn Adjustment
Fitting a Lucar Connector
Making a 1 Ohm Test Resistor
Starter Motor (Electrical)
Wiring Diagrams
ROUTINE MAINTENANCE
Breaking in
Routine Maintenance- Introduction
Maintenance Table
Engine, Gearbox and Primary oil Service
Swing Arm Pivot Lubrication
Front Fork Oil Changing ..
Checking Hydraulic Brake Fluid Level
Checking Battery Electrolyte Level
Spark Plugs .
Tire Pressure
Adjusting Cam Timing Chain
Rocker Clearances ..
Ign. Timing Contact Breaker Points
Auto Advance Unit
Engine Camshaft Chain
Chain Adjustment
Carburetor Adjustment
Clutch Adjustment
Steering Head Bearing
Disc Brakes Adjustment
Isolastic Adjustment
Suspensory Spring Adjustment
Disc Brakes Maintenance
Tracing Trouble
H1, H3, H4
H2, H5
H6, H7, H8
H9
H10
H10
H11
H12
J1
J2
J3
JA
J5
JE, J7
J8
J9
J10
J11, J12, J13
J12, (C39, C40)
J14
J15
J16, J17, J18
J19
J20
J21
J22
J23
J24
J25
J26
Fig. J15
K1
K2
K3
K4—K9
K10
K11
K12
K13
K14
K15
K16
K17
K18
K19
K20
K21
K22
K24 (C35)
K25 (G6)
K26
K27 (F12, F13)
K28 -
K29
K30
Technical Data
SECTION A
TECHNICAL DATA
FRAME, ENGINE MOUNTINGS AND REAR SUSPENSION UNITS
Steering head bearing type: Single-row bali: Double sealed.
Front and Rear engine mountings.
Adjustable Isolastic: Adjuster on Right-hand side Front.
Adjuster on Left-hand side Rear.
Ideal Free Play 0-005”/0-006” equivalent to “13 holes” turn on adjuster, Front and Rear.
ISOLASTIC MOUNTINGS ADJUSTMENT: METHOD
Engineering Instruction No. 19 refers as follows:—
1. Loosen the nut on the 1” diameter (3” A/F) through bolt at least two turns,
2. Slide the clip away from the 8 holes in the adjuster (chaincase side on the rear, timing
side on the front).
3. Turn the adjuster clockwise, as tightly as possible with tool 06-6532. Do not use extra
leverage.
Back the adjuster off 1/5 turn (13% holes).
5. Tighten nut on through bolt (torque wrench setting 30 Ibs./ft. 4:15 Kg/m).
6. Replace clip to cover holes in adjuster.
Rear suspension units
Type — Girling : Spring/oil damped
Total length 13 inches between centres.
Spring fitted length: 8:4 in. (213:36 mm)
Spring colour code : Red/Yellow/Red (chrome spring)
Spring rate : 126 Ib. per inch
Sping free length: 8:75 in. (222:25 mm)
SPEEDOMETER GEARING
Using Dunlop 4:10 in. x 19 in. rear tyre
Rolling radius : 12-57 in. (319-3 mm)
Revs./mile : 806
Gearbox ratio: 15/12 1:1:25
FUEL
Throttle Stop Adjuster Screw
Pilot Air Screw
Pilot Jet
Fuel Line
Fuel Tap
Air Cleaner
Fuel Tank
Petrol ..
Paraffin
ELECTRICAL
A.C. Generator
Alternator
Capacitor
Lens ..
Direction Indicators
Rear Lamp
Headlamp Rim
H.T. Lead
Assimilator
Contact Breaker
WHEELS AND BRAKES
Axle
Security Bolt
Brake Expander
Master Cylinder
Brake Lining . .
INSTRUMENTS
Odometer ….
Speedometer Gearbox
Tachometer
Idle speed adjuster
Idling screw. Volume control screw.
Idle mixture screw.
Slow running jet. idling jet.
Petrol pipe. Gas line.
Petrol tap. Gas cock. Pet cock.
Air filter. Air box. Air silencer.
Petrol tank. Gas tank.
Gasoline.
Kerosene.
Alternator.
Rotor and stator.
Condenser.
Glass.
Flashing indicators. Turn signals. Flashers
Tail lamp. Stop/tail lamp.
Headlamp bezel. Headlamp surround.
High tension lead. Plug lead.
Simulator, Actuator. Control unit.
Points. Breaker.
Spindle.
Tire lock.
Brake cam.
Main cylinder. Reservoir.
Brake facing.
Mileage recorder.
Speedometer drive box.
Rev. counter. Engine speed indicator.
- Technical Data
Technical
Data
Technical Data
WHEELS AND BRAKES
Front wheel
Rim size: WM2 — 19
Spokes — Disc brake wheel: Inner L.H. — 90° head 9 SWG 0-270 (6:9 mm) head dia.
Outer L.H. — 90% head 9 SWG 0-270 (6-9 mm) head (80° bend)
Right hand — 90° head 8 SWG 0-290 (7-35 mm) head dia.
Wheel bearing L.H.: 17 mm x 40 mm x 12 mm
Wheel bearing R.H.: NM 17721: 17 mm x 40 mm x 16 mm (Double row).
Bearing housing [.D.: 1-5732 in./1-5740 in. (39-96 mm/39-98 mm)
Spindle (bearing/dia.) : 0-6671/0-6670 in. (16:945/16:942 mm)
Tire size: 4-10X19
Tire pressure : 26 Ibs./psi (1-83 kg/sq. cm.). Refer “Tire Pressures” section for permissible
variation
Tire diameter (Dunlop) : 26:46 in. (672 mm)
Sectional width (Dunlop): 4 in. (101-6 mm)
Front brake (disc) & Rear brake (disc) using common components.
Type: Disc — hydraulically operated
Pad type: Steel backed, moulded and bonded friction material
Pad friction area diam.: 1-65 in. (41:9 mm)
Pad new thickness (Pad and backing together) : -38/-37 in. (9-652/9-398 mm)
Pad minimum thickness 0-0625 in. (1:5875 mm)
Disc diameter: 10-70 in. (271-7 mm)
Disc width at friction area: 0-260/0-250 in. (6-604/6-35 mm)
Brake fluid type: Lockheed series 329 Hydraulic Fluid for disc brakes.
(Complies with U.S. Safety Standard 1186).
Rear wheel
Rim size: WM2 — 19
L.H.Outer 6-155” (153-8 mm) x 9 SWG Acute Angle Head
Rear Spokes: L.H. Inner 6-140” (155-9 mm) x 9 SWG Obtuse Angle Head
Right hand 8-075” (205-1 mm) x 9 SWG (Fitted in Hub Cone).
Wheel bearing L.H.: 17 mm x 40 mm x 12 mm (Single sided rubber seal).
Wheel bearings: Ball Journal: L.H. 17 mm x 40 mm x 12 mm/R.H. 20 mm x 47 mm x 14 mm.
Sprocket bearing: NM.17721: Double Row: 17 mm x 40 mm x 16 mm.
Tire size: 4-10 x 19 in. (104-14 x 482-60)
Tire pressure: 26 Ibs./psi (1-83 kg/sq. cm.). Refer “Tire Pressure” section for permissible
variation
Tire diameter (Dunlop) : 26-46 in. (672-084 mm)
— Tire sectional width (Dunlop) : 4 in. (101-6 mm)
ENGINE
Gudgeon Pin
Inlet Valve ..
Piston Oil Control Rin
Induction Manifold
Oil Sump
Muffler
Gasket
Engine
Banjo Bolt
Crankcase Drain Plug
Garter Type Seal
Mute
Oil Filter Gauze
CLUTCH
Clutch Lining
Primary Chaincase ..
Clutch Operating Arm
Clutch Sprocket
GEARBOX
Gearbox
Gear Lever
Selector Fork
Countershaft
Countershaft Sprocket
Kickstarter
FRAME
Frame Rails
Oil Tank
Battery Tray
Crankcase Shield
Accessory Cover
Grab Rail
Footrest …
Passenger Footrest ..
Prop. Stand
Frame ..
Swinging Arm
Suspension Unit
FORK
Front Fork
Main Tube
Fork Slider
GLOSSARY OF PART NAMES AND ALTERNATIVES
Piston pin. Small-end pin. Wrist pin.
Intake valve.
Piston scraper ring.
Inlet manifold. Intake manifold.
Oil pan. Oil reservoir. Sump tray.
Silencer. Expansion box.
Joint. Sealing washer.
Motor.
Pipe union bolt.
Sump plug.
Spring pressure seal.
Sound deadener.
Gauze strainer.
Friction plate.
Oil bath. Transmission case.
Clutch thrust mechanism.
Clutch drum. Clutch housing.
Transmission.
Change speed lever. Gearshift lever.
Change speed fork. Shift fork.
High sleeve gear. Output gear.
Final drive sprocket. Gearbox sprocket.
Starter pedal.
Frame tubes.
Oil reservoir.
Battery carrier.
Sump shield. Skid plate. Bash plate. Rock
guard.
L.H. side cover.
Sissy bar. Passenger handhold.
Footpeg.
Pillion footrest. Buddy peg.
Side stand. Jiffy stand.
Chassis.
Swinging fork. Pivoting fork.
Rear shock absorber. Shock.
Telescopic fork. “Roadholder” fork.
Front suspension.
Stanchion.
Bottom member. Sliding member.
Technical Data
Front forks
Type: Telescopic, hydraulically damped, internal springs
Main tube 0.D.: 1-3589/1-3574 in. (34-518 mm/34-480 mm)
Top bush fitted 1.D.: 1-3595/1-3604 in. (34-531/34-556 mm)
Bottom bush O.D.: 1-4979/1-4990 in. (38:049 mm/38:075 mm)
Fork slider !.D. : 1-4995/1-5010 in. (38-087/38-:125 mm)
Spring — No. of coils: 754 approx.
Free length: 18-687 in. (474-65 mm)
Rate: 36-5 Ib./in. (6:52 kg/cm) Red paint marked
Steering crown lug and stem
Stem diam. at bearing areas: 0-9840/0-9836 in. (24-97/24-96 mm)
Fork tube top nut hexagon size: 1-3125/1-3005 in. (33-33/33-03 mm)
Head bearing spacer length: 5-06 in. (128-524 mm)
Fork leg capacity: 150 cc (5 fl. 0z.) each leg
Total fork movement: 6 in. (15-24 cm)
ELECTRICAL
System voltage: 12 volt — Positive earth
Alternator type: RM23: 180 watts.
Rectifier type: 2DV. 406.
Zener diode type: Z D 715. 2 OFF.
Battery type: Norton Villiers 066515; Yuasa YB.14.L or B.64.12. 12 volt.
Battery rating: 13AH at 10 hour rate.
Coi! type: 17M6 — 2 OFF.
Ballast resistor type: 3 BR.
Contact breaker type: 10CA.
Warning light assimilator type : 066393 standard / 066392 Canada
Fuse rating : 35 amp (174 amp continuous rated)
Direction indicator flasher unit type : 8 FL.
Capacitor: Lucas 2MC.
Starter Motor: Prestolite MGD.4111.
Solenoid for Starter: Prestolite SAZ 420IN.
Brake light switch: 2SH. 2 OFF,
Condenser Pack: Lucas 2CP.
Reflector: Lucas RER14.
Horn: Lucas 9H.
Master Switch: Lucas 149SA. standard: Lucas 30825( Canada only)
Lock Master Switch: Wilmot Breadon 1/6545.
Bulbs:
Headlight: STD Type 370 — 12 volt — 45/40 watt. Continental Type 410 — 12 volt —
45/40 watt. France Type 411 — 12 volt — 45/40 watt.
Quartz Halogen
Headlamp Bulb: STD Type 463 — 12 volt — 60/55 watt. Continental Type 472 —
12 volt — 60/55 watt.
Tail light/stop light : Type 380 — 12 volt — 21/6 watt, transverse offset pin
Parking light: Type 989 — 12 volt — 5 watt, coil, miniature bayonet cap
Direction indicator lights: Type 382 - 12 volt - 21 watt
Warning lights type : Type 281 — 12 volt - 1-2 watt, coil, sub-miniature
Warning Lights:
Maker: Pistor & Kronert.
Complete Replacement Unit.
Amber: 06-5734
Green: 06:5735 | Type P & K
Blue: 06-5736 ( 1208/6CR A1/1N.
Red: 06-5737
Speedo Tacho Bulbs: Type 643 — 12 volt — 2-2 watt.
Technical Data
ENGINE
Specification:
Capacity : 828 cc (60-5 cu. in.)
Bore: 3-030 in. (77 mm)
Stroke : 3-503 in. (89 mm)
Max. Torque : 56 Ib./ft. at 5000 r.p.m.
Peak Power - 5,800 r.p.m.
Compression Ratio: 81 :1
Crankshaft
Material : EN16
Big end journal diameter: 1-7509/1 7504 in. (44-472/44-460 mm)
Crankcheek bolts: EN 16 S
Balance factor: 63% Dry, 52% Wet. 23-55 oz (667-6 gms) on each journal
Permissible end Float: 0-:010”/0-024” (0-254 mm/0-610 mm)
Main bearings:
Drive side and Timing side: 30 mm x 72 mm x 19 mm Special Roller (Single Lipped)
Connecting rods
Material : Aluminium alloy BS.L83 or 2L65 or L77
Length between centres : 5-877/5-873 in. (129-276/129-274 mm)
Big end eye |.D.: (Less shells cap bolted on) 1-8950/1-8955 in. (48-133/48-145 mm)
Width at big end eye : 1-010/1-008 in. (25-65/25-60 mm)
Rod side clearance: 0-013 — 0-016 (0-330/0-406 mm)
Rod end clearance: Less than 0-001 (0-0254 mm)
Pistons
Material : BS.1490 — LM..13WP
Wrist pin boss |.D.: 0-6869/0-6867 in. (17-447/17-442 mm)
Diameter: bottom of Skirt 3-028/3-0271 in. (76-888/76-913 mm) std. bore
Piston rings
Type: Top chrome compression. Second compression.
Taper. “S.E.” oil control.
Top ring fitted gap: 0-010 — 0-012 in. (0-254/0-305 mm)
Middle ring (taper) fitted gap: 0-008 — 0-012 in. (0-203/0-305 mm)
Wrist pins (Gudgeon pins)
Length: 2-559/2-544 in. (65 mm/64-619 mm)
Diameter: 0-6869/0:6867 in. (17-447 mm/17:442 mm)
Technical Data
Cylinder block
Material: Cast iron
Finished size: Grade A 3:0315/3:0320 in.
Grade B 3:0320/3:0325 in.
Cylinder head
Material :
Valve seat angle :
inlet port nominal dia. :
Ex. port nominal dia. :
Ex. ring thread size:
Camshaft
Material :
Maximum lift — inlet
exhaust:
Base circle dia. :
Bearing journal dia. :
Camshaft bushes |
Fitted |.D. (Left bush) :
Fitted 1.D. (Right bushes) :
Tappets
RR 53 B
45°
14 in. (28-573 mm)
14 in. (31-75 mm)
1-997 in. x 14 T.P.l.
(50-93 mm)
EN 32 B
0-332 in. (8-432 mm)
0-322 in. (8:178 mm)
0-885 in. (22-479 mm)
0:8735 in. (22-187 mm)
0-8750 in. (22-225 mm)
08750 in. (22-225 mm)
Material: Cast iron Grade 14 — stellite tipped
Push rods
Material: Heat treated Dural tube “B” or ”S”
Inlet — assembled length: 8-166/8:130 in. (207-416/206-466 mm)
Exhaust-assembled length: 7-321/7:285 in. (186:053/185:039 mm)
Rockers
Material: EN33
Rocker ratio — inlet: 1:13:1
Rocker ratio — exhaust: 1:13 1
Bore diameter: 0-4998/0-5003 in. (12-694/12-708 mm)
Adjuster thread size : 9:39 mm x 26 TPI. Whit Form
Technical Data
Rocker shaft
Diameter: -4988/:4985 in. (12:669/12-661 mm)
Valve (tappet) Clearances (engine cold)
Inlet: -006 in. (0-15 mm)
Exhaust: -008 in. (0,2 mm)
Valve Lift
Inlet & Exhaust 0-375 in. (9:525 mm)
Valve duration : (excluding ramps)
1529
Valves
Material: Inlet — EN52 — Chrome plated stem
Ex. — KE965 — Chrome plated stem
Inlet — head dia. : 1-490 jn. (37-846 mm)
stem dia. (plated area): 0-311 5/0-3105 in. (7-91 2/7-886)
Exhaust — head dia. : 1-302 in (33-0708 mm)
stem dia. : 0-3115/0-3105 in. (7-912/7-886 mm)
Velve guides
Inside dia. : 0-3145/0-3135 in. (7-988/7-962 mm)
Outside dia. : 0-6265/0-6260 in. (15-913/15-900 mm)
Heat resisting washer material : Tuffnol grade ASP
Heat resisting washer thickness: 0-062 in. (1-574 mm)
Inlet Exhaust
Valve springs —
Inner — free length : 1-482 in. (37-642 mm) 1-197 in. 1:222 in.
Fitted length (30-40 mm) (31-04 mm)
Outer — ‘ree length : 1-618 in. (41-097 mm) 1-259 in. 1-284 in.
Fitted lergth (31:98 mm) | (32-61 mm)
Valve Spring Collapse
Minimum acceptable free lengh: Outer 1-500 in (38-100 mm)
Inuer 1-375 in (34-925 mm)
Valve timing Ymeasured at ‘013 in. (-3302 mm)
cam lift
Intet opens BTDC 50°
Inlet closes ABDC 74°
Exhaust opens BBDC 82°
Exhaust closes ATDC 42°
Intermediate timing gear
Bush material: Phosphor bronze
Bush finished dia. : 0:5627/0-5620 in. (14-292/14:274 mm)
Intermediate gear shaft dia. : 0-561 5/0:5610 in. (14-262/14-249 mm)
GENERAL GUIDANCE TABLE - TORQUE RECOMMENDATIONS
BOLTS & NUTS — TIGHTENING TORQUES: LBF/FT.
(From G.K.N. — Davis & Timmins Ltd.).
N.B. These figures are for “raw material” fasteners (viz. unplated). Lubrication, plating, and
hardened mating faces make bolts easier to turn and therefore lower torques should be
used.
Recommended
Torque for UNC UNF BSW BSF
UNF-S. cond.
Plated ed. TAE A & A & A &
Bolts Condition B S Vv B S Vv B S у В 5 у
a5 |Ibs./ft a 2 | 4 21 | 5
OD
SE No. 10 2 | 41
2
SG 2 BA 23 | 5
g= | 8 1 4 | в | 12 | 4 | 11 | 14 | 4 | В | 12 | 4 | 9 | 14
Se
“© 15 E 7 | 20 | 25 | 8 | 22) 28 | 7 | 17 | 25 | 8 | 18 | 27
or
E
88 | 25 3 13 | 35 | 45 | 14 | 40 | 50 | 13 | 30 | 45 || 14 | 32 | 49
‚ ©
E | 40 5 21 | 56 | 73 | 22 | 62 | 81 || 21 | 47 | 72 || 22 | 51 | 78
Zo.
S524 60 1 31 | 85 | 111 || 36 | 96 |125| 31 | 70 | 107 || 34 | 77 [118
552
2 8% | 80 2 46 | 123] 160] 51 | 137] 180] 46 1105| 1601 50 |112|173
E >.
DB 5 64 |170|212| 72 |192 |238 | 63 |145 | 210 | 68 | 155 | 224
- 5
297 3 113 | 300 | 393 || 126 | 335 | 435 || 113 | 255 | 390 || 118 | 268 | 410
a r= С
Soc 2 182 | 485 | 632 || 200 | 535 | 695 || 182 | 410 | 628 || 191 | 432 | 660
Nc .
£08 1 274 | 730 | 950 | 297 | 795 [1000] 272 | 620 | 945 | 288 | 650 | 995
о ес
338 13 |388|1035)1345) 433|1160/1500) 388|875|1330) 410|930|1420
Bright mild steel: En 1A is in Condition B (28 tonf/in?) Brass has tensile strength 25 tonf/in?.
B.S. 1768
BOLTS NUTS
conan | Mire Shoat | ce |, [Sgt
A&B 28 О 120/235 А, В, Р
Р 35 1 163/240 S |
S 50 3 183/300 T
T 55 5 270/335 V, X
V 65
X | 75
Dimensions of Bolts and Nuts: BS 1768
Screw Threads (UN): BS 1580
Plating (0-06 to 0-75 dia): BS 3382 (over 0:75) BS 1706
Controlling British
Standards employed
“in manufacture
Technical Data
Camshaft chain
Size: 0-375 in. x 0-225. Single row (Endless)
No. of links: 38
Ideal adjustment: 4% in. (4-8 mm) up and down on top run of chain
Ignition timing
Fully advanced position: 28° BTDC
Contact breaker
Points gap: 0-014/0-016 in. (0-35/0:40 mm)
Centre bolt thread size: 4 in. x 26 T.P.1.
Spark plug
Type : Champion N7Y (was N6Y)
Gap: 0:023/0-028 in. (0-59/0-72 mm)
Carburetor
Type: Twin concentric float Amal 932 32 mm
Main jet: 230
Needle jet: 0-106
Needle position: Top (Weakest notch).
Throttle valve : 3%
Needle: 928/104
Choke (spray) tube: 928/107
Air filter
Element type: Oil Impregnated Foam.
TORQUE SETTINGS
Cylinder head nuts and bolts ($ in.) : 30 Ibs./ft. (4-15 Kg/m)
Cylinder head bolts (+ in.) : 20 Ibs./ft. (2:75 Kg/m)
Cylinder base nuts ($ in.) : 25 Ibs./ft. (3-45 Kg/m)
Cylinder base nuts (5 in.) : 20 Ibs./ft. (2-75 Kg/m)
Cylinder through bolt: 30 Ibs./ft. (4:15 Kg/m)
Connecting rod nuts. : 25 Ibs./ft. (3-45 Kg/m)
Rocker spindle cover plate bolt: 8 Ibs./ft. (1-11 Kg/m)
Crankshaft Flywheel nuts: 30 Ibs./ft. (4-15 Kg/m)
Cam chain tensioner nuts: 15 lbs./tt. (2:07 Kg/m)
Oil-pump stud nuts: 15 Ibs./ft. (2:07 Kg/m)
Rocker feed banjo bolts: 15 Ibs./ft. (2:07 Kg/m)
Technical Data
Engine mount bolts: 25 ibs./ft. (3:45 Kg/m)
Rotor nut Crankshaft: 70 Ib./ft. (9-68 Kg/m)
Alternator mounting stud nuts: !bs./15 ft. (2:07 Kg/m)
Clutch-to-mainshaft nut: 70 Ibs./ft. (9:68 Kg/m)
Mainshaft nut: 40/50 Ibs./ft. (5:50 Kg/m)
Countershaft sprocket nut: 80 Ibs/ft.. (11:06 Kg/m)
Gearbox inner cover nuts: 12 Ibs./ft. (1:66 Kg/m)
Top gearbox fixing bolts: 55 Ibs./ft. (7-60 Kg/m)
Oil pressure release valve : 25 Ibs./ft. (3-46 Kg/m)
The part numbers referred to, are taken from the “850 Commando Parts List”, Publication No.065034.
The references following the part numbers, refer back to the parts list, as indicated below:-
The initial number refers to the group, white the number after the decimal point indicates the plate
number.
NM 25087
060361 (18-2)
27815 (17:57)
060599 (9-27)
060348 (12-4)
NM 19437 (13-2)
060348 (13-9)
063245 (1-13)
063598 (13-16)
063024 (13-31)
063246 (13-34)
061702 (13-52)
060651 (14-20)
060327 (14-22)
060029 (14-35)
063089 (14-43)
033057 (14-51)
060029 (15-6)
063598 (15-9)
20948 (15-13)
060348 (15-17)
061246 (15-18)
062240 (23-16)
060652 (16-6)
030448 (16-20)
060359 (17-18)
060345 (17-33)
060355 (17-37)
0700101 (17-43)
061911 (17-44)
27815 (17-57)
060361 (18-2)
060348 (18-24)
0700291 (18-34)
060292 (20-3)
060289 (20-2)
062240 (22-22)
26078 (22-28)
062240 (23-16)
060029 (23-21)
060618 (23-22)
060348 (23-29)
0700267 (23-37)
060678 (26:6)
Speedo cable to speedo G.B: 15 Ibs./ft. (2-07 Kg/m)
Front wheel spindle nut: 60 lIbs./ft. (8:30 Kg/m)
Front fork pinch bolt nut: 15 Ibs./ft. (2-07 Kg/m)
Kickstart pinch bolt: 25 ibf.ft. 3-46 Kgm
Carburettor stud nut and screws (12:6): 8 ibf.ft. 1-10 Kgm
Engine steady to head screw: 12 Ibs./ft. (1:66 Kg/m)
Engine steady stud nut: 12 |bs./ft. (1:66 Kg/m)
Engine front plate nut: 25 |bs./ft. (3:46 Kg/m)
Front engine mounting nut. 30 Ibs./ft. (4-15 Kg/m)
Rear engine plate nut: 30 Ibs./ft. (4:15 Kg/m)
Rear engine plate nut: 20 Ibs./ft. (2:76 Kg/m)
Centre stand nut: 45 |bs./ft. (6:21 Kg/m)
Rear wheel adjuster nut: 8 Ibs./ft. (1:10 Kg/m)
Swinging arm pivot pin bolt: 10 lbs./ft. (1-38 Kg/m)
Suspension unit nuts: 25 Ibs./ft. (3:46 Kg/m)
Prop stand nut: 60 Ibs./ft. (8:30 Ка/т)
Chain guard nut. 8 Ibs./ft. (1:10 Kg/m)
Rear side plate mounting nut: 25 |bs./ft. (3:46 Kg/m)
Main isolastic nut: 30 Ibs./ft. (4:15 Kg/m)
Footpeg nut: 40 Ibs./ft. (5:53 Kg/m)
Footrest mounting flange nut: 8 Ibs./ft. (1:10 Kg/m)
Footrest mounting bolt: 15 Ibs./ft. (2:07 Kg/m)
Nut (exhaust balance pipe clamp bolt): 7 lbs./ft. (0:97 Kg/m)
Bolt. Oil Tank mounting: 4 Ibs./ft. (0-553 Kg/m)
Oil junction block bolt. 8 Ibs./ft. (1-10 Kg/m)
Fork-Damper tube anchor bolt: 10 Ibs./ft. (1:38 Kg/m)
Stanchion top chrome nuts: 30 Ibs./ft. (4:15 Kg/m)
Nut mudguard bridge stud: 8 Ibs./ft. (1:10 Kg/m)
Steering stem nut: 30 lbs./ft. (4:15 Kg/m)
Socket pinch screw — lower yoke: 25 Ibs./ft. (3-46 Kg/m)
Front spindle — Pinch bolt nut: 10 Ibs./ft. (1-38 Kg/m)
Front spindle nut: 60 lbs./ft. (8-30 Kg/m)
Disc to hub nuts: 20 lbs./ft. (2-76 Kg/m)
Caliper to fork bolts: 30 Ibs./ft. (4:15 Kg/m)
Caliper end plug: 25 Ibs./ft. (3:46 Kg/m)
Rear wheel nut (dummy spindle): 80 Ibs./ft. (11-06 Kg/m)
Rear wheel spindle: 80 Ibs./ft. (11-06 Kg/m)
Front brake lever pivot bolt nut: 25 Ibs./ft. inches (0:29 Kg/m)
Front hydraulic hose nut: 15 Ibs./ft. (2:07 Kg/m)
Nut (balance pipe clamp bolt): 7 Ibs./ft. (0:97 Kg/m)
Silencer clip clamp-bolt nut: 9 1bs./ft. (1:24 Kg/m)
Bolt pillion footrest-plate: 25 Ibs./ft. (3-46 Kg/m)
Nut footrest-plate: 10 Ibs./ft. (1-10 Kg/m)
Nut pillion footrest pivot bolt nut: 8 Ibs./ft. (1:10 Kg/m)
Mudguard stay nut: 4 Ibs./ft. (0-553 Kg/m)
060357 (26-7)
060029 (27-5)
060348 (27-9)
062240 (27-10)
062921 (27-14)
060348 (27-21)
25607 (29-5)
062348 (29-6)
M1002/15E (29-12)
060865 (29-14)
033057 (29-33)
25607 (29-41)
22061 (29-43)
033057 (29-46)
033057 (29-49)
062321 (30-34)
GEARBOX
Ball journal bearings:
Technical Data
Front mudguard stay bolt: 10 Ibs./ft. (1-38 Kg/m)
Rear mudguard nut: 8 Ibs./ft. (1-10 Kg/m)
Rear mudguard nut. %: 15 Ibs./ft. (2-07 Kg/m)
Rear mudguard nut. 1: 8 Ibs./ft. (1-10 Kg/m)
Tail lamp-pillar nut: 2 Ibs./ft. (2:77 Kg/m)
Lift handle-clip nut. 4: 8 Ibs./ft. (1:10 Kg/m)
H.T. and Coil clip bolts: 10 Ibs./inches (0:12 Kg/m)
Spark plug: 15 Ibs./ft. (2-07 Kg/m)
Reflector nut: 20 Ibs./inches (0:27 Kg/m)
Coil mounting bracket bolts: 8 Ibs./ft. (1:10 Kg/m)
Rectifier nut: 3 Ibs./ft. (0-42 Kg/m)
Screw (condenser pack): 2 Ibs./ft. (0:27 Kg/m)
Nut (condenser pack): 2 Ibs./ft. (0-27 Kg/m)
Zener diode nut: 24 Ibs./inches (0-27 Kg/m)
Horn nut: 8 Ibs./ft. (1-10 Kg/m)
Headlamp bolt: 15 Ibs./ft. (2:07 Kg/m)
Mainshaft (Clutch end) Ball journal 14 in. x 24 in. x # in.
Mainshaft (K/S end) : Ball journal § in. x 13% x in.
Layshaft (Clutch end) : Ball journal 17 mm x 40 mm x 12 mm
Reductions
4th (HIGH): 1:1
3rd: 1-21 :1
2nd : 1-70 :1
1st (LOW): 2-56 :1
No. of teeth on pinions
Layshaft: 4th 18t
Layshaft: 3rd 20t
Layshaft: 2nd 24t
Layshaft: 1st 28t
Mainshaft: 4th 23t
Mainshaft: 3rd 21t
Mainshaft: 2nd 18t
Mainshaft: 1st 14t
Theoretical road speeds using various countershaft (gearbox) sprockets
Table assumes standard sprockets: Engine 26T
Clutch 57T | Primary drive ratio 2:192:1
Rear 42 T
Sprocket Teeth 19 20 21 22 23
Overall Gear Ratio 4-84 4-60 4-38 4:18 3-99
Engine 6000 92 97 102 106 112
APM 6500 99 105 110 115 121
7000 107 113 119 124 130
Technical Data
Overall Ratios 1976 Mark II! 1975 Mark II!
With 19T Gearbox USA/Canada With 21T Gearbox |Except USA/Canada
Sprocket With 20T Gearbox Sprocket With 22T Gearbox
Sprocket Sprocket
4th (HIGH): 4-84 :1 4-60 :1 4-38 4-18 :1
3rd: 5-90 :1 5-57 :1 5-30 :1 5:10 :1
2nd: 8:25 :1 7-83 :1 7-45 1 6-84 :1
1st (Low): 12-40 :1 11-79 :1 11-20 :1 10:71: 1
Gearbox
High gear bush O.D.: 0:9060/0:9053 in. (23:012/22-995 mm)
High gear bush I|.D.: 0-8145/0-8140 in. (20-688/20-675 mm)
High gear bush fitted 1.D.: 0-8133/-8120 in. (20-657/20-625 mm)
K/S spindle bush fitted 1.D.: 1-126 in./1:124 in. (28:60/28-549 mm)
Mainshaft second gear bush fitted 1.D.: 0-8125/0-8115 in. (20-637/20:612 mm)
Layshaft third gear bush fitted I1.D.: 0-8125/0-81 in. (20-637/20-574 mm)
Layshaft first gear bush fitted 1.D.: 0-6885/0-6875 in. (17-488/17-462 mm)
Footchange spindle bush, K/S case fitted !.D.: 0:6290/0-6285 in. (15:976/15-964 mm)
Camplate/Quadrant bush fitted |.D.: 0-5005/0-4995 in. (12-713/12-687 mm)
Layshaft bush !.D.: 0-675/0-673 in. (17-145/17-094 mm)
Gearbox sprocket: 20T or 22T Standard (Alternative sprockets available — see table above)
Camplate plunger spring
Free length: 1-500 in. (38:1 mm)
Spring rate: 21 Ibs./in. (3:74 kg/mm)
Selector spindle diameter: 0-3740/0-3735 in. (9-499/9-486 mm)
Selector fork bore: 0:3755/0-3745 in. (8-537/9:525 mm)
Primary Transmission and Rear Chain
Engine sprocket no. of teeth: 26
Primary chain details 92 pitches: 0-375 in. x 0-250 in. Triple row
Rear chain details 100 pitches: 0-400 in. x 0-380 in. simple type (99 pitches with 20T gearbox
sprocket).
Clutch chainwheel no. of teeth: 57
Clutch pushrod — length: 9-813/9-803 in. (244-250/243-996 mm)
Clutch pushrod — diameter : 0-237/0-232 in. (6-019/5-892 mm)
Clutch operating ball diameter : 4 in. (12-70 mm)
Clutch operating body lock ring thread size: 41:4 mm x 20 TPI
Clutch type : Multi plate, diaphragm spring
Clutch friction plate no. off: 5
Clutch friction plate thickness: 0:148/0:142 in. (3-759/3-607 mm)
Clutch friction plate material : Sintered bronze
Clutch centre bearing specification: Deep grove ball bearing — one dot
OD 62 mm, ID 35 mm, Width 14 mm
Corner rad 1-5 mm
Clutch adjuster dia. and thread: 4 in. x 20 UNF 2A
Clutch adjuster length: 0-904 in. x 0-894 in. (22:962/22:708 mm)
Technical Data
CAPACITIES
(All tanks of steel construction from 1975)
Fastback fuel tank capacity: 3% Imp. galls (15 litres) 3-9 U.S. galls
L.R. Fastback fuel tank capacity: 4 galls. (18 litres) 4-8 U.S. galls
Roadster fuel tank capacity: 2:7 Imp. galls
(12 litres) 3:2 U.S. galls.
S.S. Hi-rider fuel tank capacity: 2 Imp. galls (9 litres) 2-4 U.S. galls
Interstate fuel tank capacity: 5-5 Imp. galls
(25 litres) 6-6 U.S. galls.
Interpol fuel tank capacity: No radio: 4 Imp. galls. (18 litres) 4-8 U.S. galls.
Radio insert: 3% Imp. galls. (16 litres) 4-2 U.S. galls.
Oil tank: 5 Imp./6 U.S. pints, 2-8 litres
Gearbox: 0-75 Imp./0-9 U.S. pints, 0:42 litres
Front forks: 150 cc (5 fl. 0z.) each leg
Primary chaincase : 200 cc (7 fl. oz.)
MISCELLANEOUS DATA
Height — 40:75 in. (103:5 cm)
Hi-Rider only — 50+ in. (127-6 cm)
Length: 87-5 in. (222 cm)
Wheelbase: 56-75 in. (144 cm)
Dry Weight includes battery, but not petrol, oil and tools
Roadster 465 Ib. (211 kg) Interstate 475 Ib. (215 kg)
(For motorcycle equipped with 4-10 in. x 19 in. tyres front and rear)
Weights rounded to nearest 5 Ibs to allow for variations in materials of construction;
castings, forgings, tubes, etc. ranging 5%
Ground clearance: 6 in. (15 cm)
Width: 26 in. (66 cm)
Overall length of exhaust system (from flange at exhaust port end of pipe to tip of
muffler: 65 in. (165-1 cm)
Exhaust system maximum diameter: 3-5 in. (8-92 cm)
Maximum theoretical road speed 122 m.p.h. (196-336 K.p.h.)
Road speed at 1000 r.p.m. in gears (20T sprocket)
Bottom: 6:61 m.p.h. = (10-64 K.p.h.)
Second: 9-96 m.p.h. = (16:03 K.p.h.)
Third: 13-86 m.p.h. = (22:30 K.p.h.)
Top: 16:92 m.p.h. == (27-22 K.p.h.)
Total movement of front forks: 6 in. (15:2 cm)
Turning circle (full circle) : 17 ft. 10 in. (518-16 cm)
Gross vehicle rating : 880 Ib. (399:16 Kg)
Centre of gravity: 19# т. (501:65 mm) above ground unladen
Seat height (nominal) : 33 — 34 in. (838-2 — 863-6 mm) dependent on model
Technical Data
SPECIAL WORKSHOP TOOLS
060941
060949
060999
061015
064298
ET2003
063964
063965
064292
063968
063969
063970
060942
061359
Engine sprocket (clutch hub and cam sprocket) puller (with longer studs: Mark Il!)
Auto advance unit lock washer (for static timing)
Clutch diaphragm spring tool
Clutch lock tool (locks clutch body with plates removed)
Rocker spindle and auto advance slide hammer
Crankshaft timing pinion extractor
Valve guide screw-type extractor and inserter
Peg spanner (wrench) for wheel bearings and disc caliper
Contact breaker seal and crankshaft-to-timing cover seal drift set
Exhaust lockring “C” spanner
Valve seat cutting tool complete
Roller bearing race extractor (with longer studs for Mark 111)
Steering head adjustment spanner (Pre 1971)
Contact breaker oil seal guide
NM12093 £ in. box spanner
064622
Strap wrench
Note: A separate illustrated tool list part no. 604621 is available for 1973 models. This will be up-
dated as soon as possible to include Mark Ill special service tools.
Conversion Tables
MILLIMETRES TO INCHES
mm. 0 10 20 30 40 50 60 70 80 90
0 -39370 | 78740 | 1-18110 | 1:57480 | 1-96851 | 2-36221 | 2.75591 | 3-14961 | 3-5433
1 -03937 | -43307 | -82677 | 1-22047 | 1-61417 | 2-00788 | 2:40158 | 2:79528 | 3:18891 | 3:5826
2 -07874 | -47244 | -86614 | 1-25984 | 1-65354 | 2-04725 | 244095 | 2-83465 | 3-22835 | 3-6220
3 -11811 | -51181 ‘90551 | 1-29921 | 1-69291 | 2-08662 | 2-48032 | 2-87402 | 3-26772 | 3-6614
4 15748 | 55118 | 94488 | 1:33858 | 1-73228 | 2-12599 | 2-51969 | 2-91339 | 3-30709 | 3-7007
5 19685 | -59055 | -98425 | 1-37795 | 1-77165 | 2-16536 | 2-55906 | 2-95276 | 3-34646 | 3-7401
6 -23622 | -62992 | 1-02362 | 1-41732 | 1-81103 | 2-20473 | 2-59843 | 2-99213 | 3-38583 | 3-7795
7 -27559 | -66929 | 1-06299 | 1-45669 | 1-85040 | 224410 | 2-63780 | 3-03150 | 3:42520 | 3:8189
8 -31496 | -70866 | 1-10236 | 1-49606 | 1-88977 | 2-28347 | 2-67717 | 3-07087 | 3-46457 | 3-8582
9 -35433 | -74803 | 1-14173 | 1-53543 | 1-92914 | 2-32284 | 2-71654 | 3-11024 | 3-50394 | 3-8976
MILLIMETRES TO INCHES (DECIMALS OF)
1/1000 1/100 1/10
mm. inches mm. inches mm. inches
0-001 | -000039 0-01 -00039 0-1 -00394
0-002 | -000079 0-02 :00079 0-2 -00787
0-003 | -000118 0-03 -00118 0-3 -01181
0-004 | -000157 0-04 -00157 0-4 -01575
0-005 | -000197 0-05 -00197 0:5 -01969
0-006 | -000236 0-06 -00236 0-6 102362
0-007 | -000276 0:07 -00276 0-7 -02756
0-008 | -000315 0-08 -00315 0:8 -03150
0-009 | -000354 0-09 00354 0-9 103543
INCHES TO MILLIMETRES (DECIMALS OF)
Inches 0 10 20 30 40 1/1000 1/100 1/10
0 254-0 | 508:0 | 762-0 | 1016-0 inches mm. inches mm. inches mm.
1 254 | 279-4 | 5334 | 787-4 | 1041-4 -001 | -0254 -01 ‘254 1 2-54
2 50-8 | 304-8 | 558-8 | 812-8 | 1066-8 -002 | -0508 02 508 2 5-08
3 76-2 | 330-2 | 584-2 | 838-2 | 1092-2 -003 | -0762 -03 762 К 7:62
4 1016 | 355.6 | 609-6 | 8636 | 1117-6 -004 | 1016 04 | 1.016 4 | 1016
5 127-0 | 381.0 | 635-0 | 889.0 | 1143-0 005 | -1270 -05 | 1:270 5 | 12:70
6 152-4 | 406-4 | 660-4 | 914.4 | 1168-4 -006 | -1524 -06 | 1-524 6 | 1524
7 177-3 | 431-8 | 6858 | 939.8 | 1193.8 -007 | 1778 07 | 11-778 | | -7 (17-79
8 203-2 | 457-2 | 711-2 | 965-2 | 1219-2 -008 | -2032 -08 | 2-032 8 | 2032
9 228:6 | 482.6 | 7366 | 990-6 | 1244-6 -009 | -2286 09 | 2-286 9 | 22-86
Fractions Decimals | mm. Fractions Decimals mm. |
1/64 | 015625 -3969 33/64 | 515625 13-0969
1/32 03125 | 7937 17/32 53125 13-4937
3/64 | -046875 11906 | of 35/64 | 546675 | 13-8906
1/16 -0625 1:5875 > 9/16 -5625 142875
5/64 | 078125 1.9844 | À 37/64 | 578125 | 14-6844
3/32 09375 | 23812 © 19/32 59375 15-0812
7/64 | 109375 27781 | © 39/64 | 609375 15-4781
1/8 125 | 31780 — a 5/8 625 15-875
т 9/64 | 140625 359 | y 41/64 | -640625 16-2719
5/32 15625 3-9687 a 21/32 -65685 16-6687
11/64 | 171875 _ 4-3656 > 43/64 | -671875 17-0656
3/16 1875 47625 | D | 11/16 6375 17-4625
13/64 | -203125 51504 | © 45/64 | 703125 17-8594
7/32 -21875 5.5562 | 23/32 71875 18-2562
a 15/64 | 234375 59531 | Y 47/64 | 734375 | 18-6531
1 25 63500 | O | 3/4 75 19-05
17/64 | 2656625 6-7469 > 49/64 | -765625 19-4469
9/32 ‘28125 71437 | E 25/32 -78125 19-8437
19/64 | 296875 75006 | © 51/64 | -796875 | 20-2406
5/16 3125 79375 | M | 13/16 8125 20-6375
21/64 | 328125 83344 | = 53/64 | 828125 | 21-0344
11/32 -34375 8-7312 © 27/32 84375 21:4312
23/64 | -359375 91281 | 4 55/64 | 859375 | 21-8281
3/8 375 95250 | © | 7/8 875 22-225 |
25/64 | -390625 9.9219 = 57/64 | -890625 | 22-6219
13/32 -40625 10-3187 = 29-32 -90625 23-0187
27/64 | -421875 10-7156 > 59/64 | -921875 | 23-4156
7/16 4375 11-1125 de 15/16 9375 23-8125
29/64 | 453125 11-5094 5 61/64 | -953125 | 24.2094
15/32 46875 11-9062 31/32 -96875 24-6062
31/64 | -484375 12-3031 63/64 | -984375 | 25-0031
1/2 5 12-700 1 25-4
Conversion Tables
U.N.E.F.
Dia. No of thds.
1/4 in. 32
5/16 in. 32
3/8 in. 32
7/16 in. 28
1/2 in. 28
9/16 in. 24
5/8 in. 24
11/16 in. 24
3/4 in, 20
13/16 in. 20
7/8 in. 20
15/16 in. 20
1 in. 20
1-1/16 in. 18
1-1/8 in. 18
1-3/16 in. 18
1-1/4 in. 18
1-5/16 in. 18
1-3/8 in. 18
1-7/16 in. 18
1-1/2 in. 18
1-9/16 ins. 18
1-5/8 in. 18
1-11/16 in. 18
U.N.F.
Dia. No. of thds.
1/4 in. 28
5/16 in. 24
3/8 in. 24
7/16 in. 20
1/2 in. 20
9/16 in. 18
5/8 in. 18
3/4 in. 16
7/8 in. 14
1 in. 12
1-1/8 in, 12
1-1/4 in. 12
1-3/8 in. 12
1-1/2 in. 12
B.A.
Dia. of | Thds.
No. bolt | per inch
0 -2362 25:4
1 ‘2087 28-2
2 1850 31-4
3 ‘1614 34-8
4 1417 38-5
5 1260 43-0
6 1102 47-9
7 -0984 52-9
8 0866 59-1
9 ‘0748 65-1
10 0669 72:6
11 -0591 81.9
12 "0511 90-9
13 ‘0472 | 102.0
14 | 0394 | 109.9
15 '0354 | 120.5
16 "0311 | 133:3
U.N.C.
Dia. No. of thds.
1/4 in. 20
5/16 in. 18
3/8 in. 16
7/16 in. 14
1/2 in. 13
9/16 in. 12
5/8 in. 11
3/4 in. 10
7/8 in. 9
1 in. 8
1-1/8 in. 7
1-1/4 in. 7
1-3/3 in. 6
1-1/2 in. 6
1-3/4 in. 5
2 in. 4-1/2
B.S.W.
Dia. of | Threads
(inch) | inch
1/4 20
5/16 18
3/8 16
7/16 14
1/2 12
9/16 12
5/8 11
11/16 11
3/4 10
13/16 10
7/8 9
15/16 9
1 8
THREADS
B.S.F.
Dia. of | Threads
bolt per
(inch) inch
7/32 28
1/4 26
9/32 26
5/16 22
3/8 20
7/16 18
1/2 16
9/16 16
5/8 14
11/16 14
3/4 12
13/16 12
7/8 11
1 10
1-1/8 9
1-1/4 9
1-3/8 8
1-1/2 8
1-5/8 8
Conversion Tables
WIRE GAUGES
DRILL SIZES (INCHES)
No. of Imperial Standard
Gauge Wire Gauge
Inches Millimetres
1 -300 7-620
2 -276 7-010
3 ‘252 6-400
4 ‘232 5-892
5 ‘212 5-384
6 192 4-676
7 176 4:470
8 :160 4-064
9 ‘144 3-657
10 128 3-251
1 116 2-946
12 104 2-641
13 ‘092 2:336
14 -080 2:-032
15 -072 1:828
16 -064 1-625
17 -056 1-422
18 ‘048 1-219
19 ‘040 1-016
20 036 314
21 ‘032 812
22 028 711
23 024 609
24 ‘022 "558
25 020 -508
26 018 -457
27 0164 416
28 0148 375
29 0136 345
30 0124 314
No. of Brown and Sharpe's
Gauge American Wire Gauge
inches Millimetres
1 +289 7-348
2 ‘258 6:543
3 -229 5-827
4 -204 5-189
5 -182 4-621
6 ‘162 4-115
7 ‘144 3-664
8 128 3:263
9 :114 2:906
10 102 2-588
11 ‘091 2:304
12 081 2:-052
13 -072 1-827
14 ‘064 1-627
15 057 1-449
16 -051 1-290
17 -045 1:149
18 ‘040 1-009
19 ‘035 911
20 "032 -811
21 "028 ‘722
22 ‘025 -643
23 -023 ‘573
24 ‘020 511
25 -018 -454
26 016 ‘404
27 ‘014 -360
28 -012 ‘321
29 011 -235
30 -010 -254
Number | Size Number | Size Letter Size
1 ‘2280 27 -1440 A -234
2 2210 28 1405 B 238
3 ‘2130 29 ‘1360 С ‘242
4 ‘2090 30 1285 D -246
5 -2055 31 -1200 E -250
6 ‘2040 32 1160 F 257
7 2010 33 1130 G ‘261
8 +1990 34 ‘1110 H 266
9 +1960 35 1100 | ‘272
10 1935 36 1065 J ‘277
11 1910 37 1040 K -281
12 -1890 38 -1015 L -290
13 1850 39 -0995 M 295
14 |-1820 40 | -0980 N 302
16 1800 41 -0960 O 316
16 ‘1770 42 ‘0935 P -323
17 1730 43 -0890 Q 332
18 1695 44 -0860 R -339
19 ‘1660 45 '0820 5 -348
20 1610 46 -0810 T -358
21 -1590 47 -0785 U -368
22 1570 48 ‘0760 Vv -377
23 1540 49 -0730 W -386
24 1520 50 ‘0700 X -397
25 ‘1495 51 -0670 Y -404
26 1470 52 -0635 Z :413
Gallons (Imperial) GALLONS Gallons (U.S.)
Imperial U.S. U.S. Imperial
Gallons Gallons Gallons Gallons
1 1:2 1 0-83
2 2:4 2 1-66
3 3-6 3 2.50
4 4-8 4 3-33
5 6-0 5 4:16
6 72 6 5-00
7 84 7 5-83
8 9-6 8 6:66
9 10:8 9 7-49
10 12-0 10 8:30
50 miles per U.S. galion
is equivalent to
60 miles per Imperial gallon.
NOTE: 1 British Gallon — 1.2 U.S. Gallons
Conversion Tables
PINTS (IMPERIAL) TO LITRES
0 1 | | 5 | 6 7 8
— _ 568 1136 1-705 2.273 2.841 3-841 3-978 4-546
} 142 710 1-279 1-846 2-415 2-983 3-652 4-120 4-688
; -284 852 1-420 | 1-989 2-657 3-125 3-125 4-262 4-830
3 426 ‚994 1:563 | 2-131 2-699 3.267 3-836 4-404 4-972
GALLONS (IMPERIAL) TO LITRES
0 1 2 3 4 5 6 7 8 9
— 4-546 | 9.002 | 13638 | 18-184 | 22-730 | 27:276 | 31-822 | 36-368 | 40-914 | —
10 | 45-460 | 50-005 | 54-551 | 59-097 | 63-643 | 63-189 | 72-735 | 77-281 | 81-827 | 86-373 | 10
20 | 90-919 | 95-465 | 100-011 | 104-557 | 109-103 | 113-649 | 118-195 | 122-741 | 127-287 | 131-833 | 20
30 | 136-379 | 140-924 | 145-470 | 150-016 | 154-562 | 159-108 | 163-645 | 168-200 | 172-746 | 177-292 | 30
40 | 181-838 | 186-384 | 190-930 | 195-476 | 200-022 | 204-568 | 209-114 | 213-660 | 218-206 | 222-752 | 40
50 | 227-298 | 231-843 | 236-389 | 240-935 | 245-481 | 250-027 | 254-473 | 259-119 | 263-605 | 268-211 | 50
60 | 272-757 | 277-303 | 281-849 | 286-395 | 290-941 | 295-487 | 300-033 | 304-579 | 309-125 | 313-671 | 60
70 | 318-217 | 322-762 | 327-308 | 331-854 | 336-400 | 340-946 | 345-492 | 350-038 | 354-584 | 353-130 | 70
80 | 363-676 | 368-222 | 372-768 | 377-314 | 381-860 | 386-406 | 390-952 | 395-498 | 400-044 | 404-590 | 80
90 | 409-136 | 413-681 | 418-227 | 422-773 | 427-319 | 431-865 | 436-411 | 440-957 | 445-503 | 450-049 | 90
MILES TO KILOMETRES
0 1 2 3 4 5 6 7 8 9
— 1609 | 3219 | 4828 | 6:437 | 8-047| g656| 11-265| 12-875 | 14-484 | —
10 | 16-093 | 17-703 | 19-312 | 20-922 | 22-531 | 24-140| 25-750| 27-359 | 28-968 | 30-578 | 10
20 | 32:187 | 33-796 | 35-406 | 37-015 | 38-624 | 40-234 | 41-843 | 43-452 | 45-062 | 46-671 | 20
30 | 48-280 | 49-890 | 51-499 | 53-108 | 54-718 | 56-327 | 57-936 | 59-546| 61-155 | 62-765 | 30
40 | 64-374 | 65-983 | 67-593 | 69-202 | 70-811 | 72-421 | 74-030 | 75-639 | 77-249 | 78-858 | 40
50 | 80-467 | 82-077 | 83-686 | 85-295 | 86-905 | 88-514 | 90-123| 91-733 | 93-342 | 94-951 | 50
60 | 96-561 | 98170 | 99-780 | 101-389 | 102-998 | 104-608 | 106-217 | 107-826 | 109-436 | 111-045 | 60
70 | 112-654 | 114-264 | 115-873 | 117-482 | 119-092 | 120-701 | 122-310 | 123-920 | 125-529 | 127-138 | 70
80 | 128-748 | 130-357 | 131-967 | 133-576 | 135-185 | 136-795 | 138-404 | 140-013 | 141-623 | 143-232 | 80
90 | 144-841 | 146-451 | 148-060 | 149-669 | 151-279 | 152-888 | 154-497 | 156-107 | 157-716 | 159-325 | 90
MILES PER GALLON (IMPERIAL) TO LITRES
PER 100 KILOMETRES
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22-60
21-73
20-92
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4:71 | 70 4-04
4:63! 71 3:98
4:55 | 72 3-92
4:48 | 73 3:87
4:41 | 74 3-82
4:35 | 75 3:77
4-28 | 76 3:72
4-22 | 77 3:67
4:16 | 78 3:62
4:10 | 79 3-57
Conversion Tables
KILOGRAMS PER SQUARE CENTIMETRE
POUNDS PER SQUARE INCH TO
0 1 2 3 4 5 6 7 8 9
— 0:070 0:141 0-211 0-281 0-352 0-422 0-492 0-562 0-633 —
10 0-703 0-773 0-844 0-914 0-984 1-055 1-125 1-196 1-266 1-336 | 10
20 1-306 1-476 1-547 1-617 1-687 1-768 1-828 1-898 1-969 2-039 | 20
30 2:109 2:179 2:250 2:320 2:390 2-461 2-531 2-601 2-672 2-742 | 30
40 2:812 2:883 2-963 3-023 3-093 3-164 3-234 3-304 3-375 3:445 | 40
50 3:515 3:586 3:656 3:726 3:797 3:867 3-937 4-007 4-078 4-148 | 50
60 4-218 4-289 4-359 4-429 4-500 4-570 4-640 4-711 4-781 4-851 60
70 4-921 4-992 5-062 5-132 5-203 5:273 5-343 5-414 5-484 5:554 | 70
80 5-624 5-695 5-765 5-835 5-906 5-976 6-046 6117 6-187 6-257 | 80
90 6-328 6-398 6-468 6-538 6-609 6-679 6-749 6-820 6-890 6-960 | 90
POUNDS TO KILOGRAMS
0 1 2 3 4 5 6 7 8 9
— 0-454 0-907 1-361 1-814 2:268 2:722 3:175 3-629 4-082 | —
10 4-536 4-990 5-443 5-987 6-350 6-804 7-257 7:711 8-165 8-618 | 10
20 9-072 9-525 9-079 10-433 10-886 11-340 | 11-793 | 12-247 | 12-701 | 13-154 | 20
30 | 13-608 14-061 14-515 14-968 15-422 15-876 | 16-329 | 16-783 | 17-237 | 17-690 | 30
40 | 18-144 18-697 19-051 19-504 19-953 20-412 | 20-865 | 21-319 | 21-772 | 22-226 | 40
50 | 22-680 23-133 23-587 24-040 24-494 24-948 | 25-401 | 25-855 | 26-308 | 26-762 | 50
60 | 27-218 27-669 28-123 28-576 29-030 | 29-484 | 29-937 | 30-391 | 30-844 | 31-298 | 60
70 | 31-751 32-205 32-659 33-112 33-566 34-019 | 34-473 | 34-927 | 35-380 | 35-834 | 70
80 | 36-287 36-741 37-195 37-648 38-102 38-855 | 39-009 | 39-463 | 39-916 | 40-370 | 80
90 | 40-823 41-277 41-731 42-184 42-638 43-091 | 43-545 | 43-998 | 44-452 | 44-906 | 90
FOOT POUNDS TO KILOGRAMETRES
0 1 2 3 4 5 6 7 8 9
— 0-138 0-277 0-415 0-553 0-691 0-830 0-968 1-106 1-244 | —
10 1-383 1-521 1-659 1-797 1-936 2:074 2:212 2-350 2-489 2:627 | 10
20 2-765 2:903 3-042 3-180 3-318 3-456 3-696 3:733 3:871 4-009 | 20
30 4-148 4-286 4-424 4-562 4-701 4-839 4-977 5-116 5-254 5-392 | 30
40 5:530 5-668 5-807 5-945 6-083 6-221 6-360 6-498 6-636 6:774 | 40
50 6:913 7:051 7:189 7-328 7-466 7-604 7-742 71-881 8-019 8:157 | 50
60 8-295 8-434 8:572 8:710 8-848 8-987 9-125 9:263 9-401 9-540 | 60
70 9-678 9-816 9-954 10-093 10-231 10-369 | 10-507 | 10-646 | 10-784 | 10-922 | 70
80 | 11-060 11-199 11-337 11-475 11-613 11-752 | 11-890 | 12-028 | 12-166 | 12-305 | 80
90 | 12-443 12-581 12-719 12-858 12-996 13-134 | 13-272 | 13-411 } 13-549 | 13-687 | 90
— Engine/Primary Transmission C
Engine
and
Primary
Transmission
Engine/Primary Transmission С.
Fig. C3 Tilting cylinder head with pushrods held into
cylinder head.
head. This releases the tension on the auxiliary
suspensory spring device which is preferably
removed intact, leaving the factory-set adjustment
undisturbed. This device is new on the Mark IH
model and provides a pre-set bias which supports
the engine unit, complementing the isolastic
mounting, minimising oscillation at low speeds
and gives smoother running generally.
If the adjustment is disturbed during dismantling,
the trunnion should be rebuilt to the dimensions
given in diagram C1(a) and the tensioning nut (x)
adjusted say, six flats per time between test runs
until the optimum smoothness is restored.
7 Detach the Suspensory spring stirrup from the
coil-bracket, noting which notch locates the loop
of the spring (usually this is on the forward
notch) lift off spark plug caps, then remove the
coil cluster complete from the frame.
To keep it clear for work on the cylinder head, we
recommend it is tied up to the handlebar at this
stage.
It is not necessary to remove the rocker covers at this
stage since they may be removed with the cylinder head.
uring removal of the head securing bolts and nuts,
leave the front centre bolt (shown in Fig. C2) till last.
8 Remove the rocker feed pipe banjo unions from
both sides of the rocker boxes and collect the cop-
per washers from both sides of the banjos. Leave
the rocker feed pipe connected to the timing case.
9 Remove both sparking plugs.
10 Remove the cylinder head securing bolts and nuts
(excepting the front centre bolt), in opposite order
as shown in Fig. C2.
11 To achieve the minimum valve lift position and
allow maximum space for removing the cylinder
head, turn the engine by revolving the rear wheel
with top gear engaged until the pistons are as near
as possible to top dead centre. The Mk Il engine
incorporates an inspection plug in the crankcase
bowl for locating T.D.C. See fig. C3.
—
2 Remove the cylinder head front centre bolt and the
head should lift slightly against valve spring pres-
sure.
Technique at this stage is to lift the cylinder head and
recess the pushrods into the head as far as possible so
that the head can be slid out between the cylinder barre!
and frame tubes. Do this as follows:
13 Lift the cylinder head from either side of the motor-
cycle, support with one hand and slide the push-
rods as far as possible into the cylinder head. Fig.
C3 shows the cylinder head tilted to the rear to
facilitate the operation.
14 Withdraw the cylinder head.
The cylinder head gasket may adhere either to the
cylinder or cylinder head. The gasket should be
removed and protected from damage since, if remai ning
in undamaged condition, it may be put into further
service.
SECTION C2
REMOVAL OF ROCKERS
In order to gain access to the inlet valve guides, the inlet
rockers and spindles may have to be removed as follows :
1 Remove the two set screws retaining each rocker
spindle cover plate (see Fig. C4).
‘
_ Fig. C1
ENGINE/PRIMARY DRIVE
SECTION C
The engine/gearbox/primary transmission can be
removed from the main frame as an assembly, bolted up
in the engine plates as in Section F1. Alternately, either
the engine or gearbox can be removed from the frame
as complete assemblies after dismantling the primary
transmission. For engine removal see Section C15 and for
gearbox removal see Section D7. Unless it is specifically
required to remove the engine complete, the simplest
method is to dismantle to crankcase level for removal as
in Section C11.
SECTION C1
REMOVING CYLINDER HEAD
Commence dismantling by removing surrounding parts
as follows:
1 Lifttwin seat clear by slackening R.H. large knurled
knob and rotating lock-key forward to release
catch, or if preferred, remove seat completely by
releasing hinge at four posidrive screws.
Remove fuse from battery negative lead.
Engine/Primary Transmission C
Fig. Cl(a) Suspensory Spring Device
2 Remove the fuel tank (see Section F9).
3 Remove the exhaust system (see Section F19).
4 Disconnect the oil separator tube from the tee-
piece at the balance pipe and remove the Car-
buretors with spacers.
5 Dismantle the Head-Steady, removing the frame
nuts first, otherwise they will tend to revolve in
the frame.
6 Remove the three 75” internal flat socket-headed
screws securing the head-steady to the cylinder
TIGHTENING SEQUENCE
Cylinder head; order of slackening and tightening
Fig. C2
- Engine/Primary Transmission €
Ne 2 Collect the cover plate, retaining plate and gaskets
as a set. In all probability these items will adhere
to one another and need not be disturbed.
3 Use service tool 064298 to extract the rocker
spindles as shown in Fig. Cb. Heat the
cylinder head gently to ease removal and avoid
damage to head or spindles. Ensure the shaft of
the slide hammer is threaded well into the rocker
spindles then slide the weight back against the
nut sharply several times and the spindle will be
drawn out.
4 Lift out the rockers and collect the plain and double
spring thrust washers. On each rocker the plain
‘ I thrust washer is outboard of the rocker and the
double spring washer inboard (see Fig. C4). Fig. C5 Extracting rocker spindles using slide hammer 064298
Proceed as follows:
1 Using a suitable overhead valve spring compressor,
SECTION C3 (proprietary spring compressors are readily avail-
able) place the fixed jaw against the valve head
and the movable jaw against the valve collar.
~ VALVE REMOVAL AND REASSEMBLY Tighten down the movable jaw to compress the
valve spring and remove the split collets. Collet
The valves need to be removed during decarbonising removal may be facilitated by the use of a small
(as described in Section C4) or when changing valve screwdriver or long nose pliers.
springs or inlet guide to stem seals. Removal of the
cylinder head (Section C1) and inlet rocker cover stud 2 Release the pressure from the compressor and
is necessary to gain access to the valves. collect the valve, springs, collars and where
Doo necessary, the inlet guide seals.
A DOUBLE SPRING PLAIN (THIN)
THRUST WASHERS THRUST WASHER 3 As each valve is removed, mark it in some way so
that it can be replaced in its original location.
4 Examine the valves for burning or damage and
grind in the cleaned up or new valves as described
in Section C7. The seats should not need to be
recut unless new valve guides have been fitted.
5 Check the valve springs for collapse. This can most
easily be done by comparison with new springs or
by checking free length to the dimension given in
Technical Data.
6 Clean all parts very thoroughly in gasoline (petrol)
and allow to dry.
о ен 7 Ensure that heat insulators are fitted between the
/ > Fig. C4 Rocker thrust washers and securing plates. exhaust valve spring seat and cylinder head.
Engine/Primary Transmission
8 With the valve spring seat in position, loose
assemble the valve (with lightly lubricated stem)
inner and outer valve spring and top valve collar.
9 Using the valve spring compressor, compress the
collar and springs and insert the split valve cotters.
10 When the collets are firmly in position in the valve
stem groove, remove the compressor. The cylinder
head is now ready to refit.
SECTION C4
DECARBONISING
After the motorcycle has been in use for some time,
carbon deposits accumulate within the combustion
chamber and exhaust ports and also the valves cease to
seal completely due to wear and a certain amount of
burning on the valve seatings. These conditions
result in a lack of compression and an increase in the
compression ratio, giving symptoms of a gradual loss of
power, poor compression and difficult starting. To
remedy these conditions, it is necessary to remove the
carbon deposits and grind the valves to their seatings
to obtain a gas-tight seal. To do so, remove the cylinder
head (Section C1) and remove the valves (Section
C3).
Uniess a carbon dispersant vat is available, the carbon
must be scraped from the combustion chambers,
exhaust ports and piston crowns. Since the cylinder
head and pistons are produced from an aluminium alloy
material which is scratched easily, the carbon must only
be removed by a soft metal or hard wood scraper which
will not damage the surface. À steel scraper or screw-
driver blade must not be used. DO NOT remove the
thin ring of carbon round the top of each cylinder bore
and leave also a ring of carbon around the edge of each
piston crown. Removal of this carbon will tend to
increase the oil consumption.
The valve stems and heads should be scraped ciear of
carbon but take care not to scratch the facings. Examine
the facings for deep pitting which would render the
valves unfit for re-use.
When all parts are perfectly clean and in good condition
grind in the valves and reassemble.
SECTION C5
VALVE GUIDE RENEWAL
The cast iron valve guides are a tight interference fit
in the cylinder head and can be removed and refitted
only after heating the cylinder head to a temperature of
150° to 200°C. A special Service Tool 063964 is avail-
able for removing and refitting the valve guides.
Proceed as follows:
1 Place the tool adaptor marked “Remover” hollow
end down over the valve guide.
2 Place the cranked and threaded stem through the
valve guide from the hemisphere.
3 Hold the cranked stem to prevent it turning and
screw on the handle (see Fig. C6). As the handle is
tightened the guide and cranked stem will be
pulled through into the remover body.
Caution: If guides seem difficult to remove, ensure
head is heated evenly. Do not force guides in or out of
their bores.
Engi ne/Primary Transmission C
“SECTION C6
RESEATING THE VALVES
After renewal of valve guides (as in Section C5) or
where the valve seats are in badly pitted condition, it is
necessary to recut the valve seats. During decarbonising
or after recutting the valve seats, the valves must be
reground.
Cutting the valve seats — Valve seat cutters, a suit-
_ able arbor and pilot are available under the following
Part Number: 063969
Arbor and pilot.
Valve seat cutter (45°).
Blending cutter .
Before commencing to cut the seats we stress that the
essence of cutting valve seats satisfactorily is to remove
the minimum of metal and to use the cutters in such a
way as to prevent possible “chatter” in the cutting pat-
tern. Proceed as follows:
1 Assemble the cutter and pilot to the arbor.
2 Enter the pilot into the valve guide from inside the
combustion chamber hemisphere.
3 Applying sufficient pressure on the arbor to give a
clean cut without “chatter”, take the first 120°
cut.
4 Repeat the operation, 120° at a time until the seats
are cleaned up free of any pitting.
5 Wash with gasoline (petrol) and blow clear any
displaced material.
6 Cut the other valve seats which are affected by
pitting.
SECTION C7
Grinding-in the valves — Examine the valve heads
for cleanlinéss and the valve stems for cleanliness,
excessive wear or pronounced scuffing. Excessive
wear or scuffing would necessitate renewal of a valve.
If the valve head facings are pitted, they can be cleaned
up on a valve facing machine though excessive
removal of material is not recommended since it would
_/fect the performance of the valve.
Grind the valve facings to the seats as follows :
10
11
Use a good quality fine grade grinding compound
and smear a little compound all round the valve
facing.
Drop the valve into position and using a backward
and forwards rotary motion by holding either the
valve head or valve stem with a suitable grinding
tool, lap the valve facing to the seat.
Lift the valve off the seat and rotate the head 180”.
Repeat the lapping and rotating operations until
there is a uniform dull grey bedding-in pattern on.
both surfaces.
Wash the affected areas free of grinding compound,
then assemble the valves and springs to the head
as in Section C3.
Fig. C7
12
Aligning rocker spindle
Test the seating of the valves by supporting the
cylinder head with valves assembled, hemispheres
upwards. Pour gasoline or kerosene (petrol or
paraffin) into each inlet port and allow 20 seconds
to elapse. If the liquid has not passed the seatings
into the combustion chambers in this time, the
lapping operation has been successful. Repeat the
operation at the exhaust valves.
Ш Engine/Primary Transmission C
New valve guides are available in oversizes : 6 Fit the handle and turn to pull the guide fully home,
+0-002 in. and +0-010 in. for the 850 engine. The into the head. If necessary the abutment can be
valve guide to cylinder head interference should be
+0015 in. — -0025 in. and if there is ovality and over-
size guides are to be fitted the valve guide bores in the
head must be reamed to suit. As a matter of course use circlips on guides, just pull down tightly enough
the improved inlet guides with valve guide-to-stem _
seals during re-assembly. -
prevented from turning by the use of a suitable key
* 19)...
in the socket provided. Be careful not to crush
to seat.
Fit new valve guides as follows:
u 4 Place the new guide in line with the bore in the
cylinder and place the adaptor marked “Replacer”
from Service Tool 063964 over the guide.
1° 7 Recut the valve seats at the points where new
5 Place the replacer stem through the cylinder head
and bore of the valve guide and locate the abut-
ment to the valve seat. cribed in Section C6.
guides have been fitted. This operation is des-
EXTRACT
GUIDE PULLED NTO
EXTRACTOR BODY
REPLACE
INSERT BODY PUSHES
GUIDE INTO HEAD
N116
1 Fig. C6 Using valve guide tool 063964 to remove a valve guide
Engine/Primary Transmission
SECTION C8
REFITTING ROCKERS
The rocker spindles must be positioned correctly to
allow satisfactory lubrication. It is recommended that the
cylinder head be heated to 150°-200°C. prior to offering
the rocker spindles, to facilitate entry and alignment.
Assembly is as follows:
1 Heat the cylinder head gently.
2 Engage a rocker spindle into the cylinder head with
flat facing rearwards on the inlet side and forwards
on the exhaust and tap it through very gently with
a soft drift until it protudes approximately 1; in.
(1-59 mm) through the outer boss into the rocker
cavity.
Fit the plain washer then the rocker in position.
4 Drive the rocker spindle part way through the
rocker and fit the double spring washer between
the other end of the rocker and the boss in the
rocker box.
5 Centralise the spring washer and drive the
spindle through until it protrudes no more than
$ in. (9-52 mm).
6 Align the rocker spindle as shown in Fig. C7.
Note: Flat on spindle faces away from centre of
head, towards rocker cover.
7 Drive the spindle home taking care that the rocker
spindle does not turn during this operation. The
spindle should be flush or fractionally below the
joint facing on the rocker box.
SECTION C9
REFITTING CYLINDER HEAD
The cylinder head should be cleaned, inspected and
overhauled as described in previous sections, and the
valves and rockers assembled. As with dismantling, the
cylinder head and pushrods should be offered as a set.
The operation is described fully below:
1 Place the cylinder head gasket in position on top
of the cylinder.
2 Turn the engine until the pistons are at top dead
centre so that there is minimum valve lift and on
assembly one pair of pushrods is fractionally
higher than the other.
3 Place the pushrods in the pushrod tunnels in the
cylinder head with the inlet pushrods (that is the
longer pair) inboard and the shorter exhaust ones,
outboard.
The cupped end of each pushrod is uppermost.
4 Take the cylinder head firmly in one hand and feed
the pushrods as far into the cylinder head as
possible, holding them with the other hand. See
Fig. C3.
5 Place the cylinder head over the cylinder, forward
end downwards and allow the pushrods to drop
down the cylinder barrel pushrod tunnels.
Note that the pushrods cannot do other than locate
on the cam followers at the lower end.
6 Starting with the pair of pushrods which are
slightly higher, engage the tops of the pushrods to
the rocker ball ends as the cylinder head is
lowered. Use an implement such as a thin screw-
driver through the exhaust rocker box to guide the
pushrods into position as shownin Fig. C8. Having
engaged the first pair of pushrods engage the
second pair in a similar manner.
The cylinder head is ready to be secured. The tightening
sequence is shown in Fig. C2.
Fig. C8
Guiding pushrods into engagement with the rockers
Bngine/Primary Transmission C
7 Fit and tighten down the short cylinder head bolt
with its washer — this Бой should be inserted
down through the cylinder head fins to the centre
front position. The cylinder head should be pulled
down to the gasket against valve spring pressure
using this bolt.
8 Check that all four pushrods are correctly engaged
to the ball ends of the rocker arms.
9 If pushrod engagement is correct, fit the four bolts
with washers on either side of the sparking plugs,
followed by a long sleeve nut under each exhaust
port and a short nut under the inlet ports, (these
are without washers) and 2 & in. nuts and
washers on the studs (no's 9 and 10 in Fig. C2)
which seal the joint by the pushrod tunnel. There
are no washers on the nuts fitted from beneath the
cylinder head.
10 Finally tighten the cylinder head bolts and nuts in
the order shown in Fig. C2. The torque settingsare :
Cylinder head bolts and nuts $ in: 30 Ibs./ft.
(3-68 Kg/m).
Cylinder head bolts 5 in. : 20 Ibs. /ft. (2:75 Kg/m)
11 Adjust the rocker clearances as described in
— Section C10.
12 Using new sealing gaskets only if the originals are
unfit for further use, refit the inlet and exhaust
rocker covers and secure with the blind nuts.
There is a washer only at the inlet rocker cover
nut.
13 Refit the carburettors with spacers as described in
Section E5, and refit the sparking plugs to avoid
washers being dropped into the engine during the
next operation.
14 Refit the suspensory spring stirrup and coil
cluster to the frame bracket.
Refit the cylinder head steady as a reversal of the
dismantling procedure, the tension on the spring
should be unaltered, providing the trunnion nut
has not moved and the loop is notched as before
on the stirrup.
IMPORTANT NOTE
Assembly line drill should be followed when replacing
the head-steady.
| To ensure that engine mountings are in repose
and avoid bias or pre-load on the head-steady rubbers,
arrange a support off the frame cradle, or have the
machine on its wheels. Never tighten up the torque
stay with the machine on its centre stand.
15 Reconnect the rocker feed pipe banjos at the
cylinder head using copper washers at each side
of the banjos. Take care that the plastic part of the
rocker pipe is clear of the rocker boxes, cylinder
head and head steady.
16 Connect the spark plug caps.
17 Reconnect the low tension leads from the contact
breaker to the main harness. These leads are
coloured white/black and yellow/black and should
be connected colour to colour. The standard
assembly procedure is white/black to right cylinder
and yellow/black to left cylinder.
18 Refit the exhaust system (Section F1 9).
19 Refit the fuel tank (Section F9) and connect the
fuel lines.
20 Refit the fuse.
21 Refit the seat and secure with the knurled side
nut and lock.
SECTION C10
ROCKER CLEARANCES
It is essential for the correct valve to rocker clearances
to be maintained to prevent excessively noisy operation
and subsequent wear or conversely to prevent insuffi-
cient clearances, a loss of compression and burning of
the valves and seats. After checking clearances at the
time of the first free service, the clearances should be
checked and corrected as necessary at 2500 mile
(4000 Km) intervals. To provide sufficient room at the
rocker boxes for satisfactory checking, the fuel tank
should be removed as in Section F9.
The correct rocker clearances are as below, checked
with the engine cold:
Inlet 0-006 in. (0-15 mm)
Exhaust 0-008in. (0-2 mm)
“ Engine/Primary Transmission Ç
NN until it /ust nips the feeler gauge. Tighten the lock-
`` Proceed to check rocker clearances as below : nut and withdraw the gauge which should not be
1 gripped tightly but should slide relatively easily
1 Remove the two exhaust and one inlet rocker from the gap. This clearance is now correct.
covers.
fully open and adjust the left side inlet valve in a
similar manner.
sparking plugs.
ROCKER
ADJUSTER B 8 Adjust the right side and left side exhaust valves
in the same sequence but using a feeler gauge in
accordance with the table of clearances.
SECTION C11
REMOVING CYLINDER AND PISTONS
Remove the cylinder head as detailed in Section C1.
The cylinder is then removed as follows :
1 Remove the four through-bolts and release the
five cylinder base nuts. It will be necessary to
raise the cylinder so that the nuts will clear the
fins. All nuts have washers except the front centre
one. Be very careful that all nuts and washers are
removed before the cylinder is lifted off.
At this stage the engine may be decarbonized as in
Section C4 or the cylinder, pistons and piston rings
N37 given attention.
Fig. C9
Checking valve clearances
3 Rotate the engine, either by the kickstart or by
turning the rear wheel forwards with fourth gear
engaged, until the left side inlet valve is fully
open.
TUN —
4 Using the correct feeler gauge (see table above for
thickness) check the rocker clearance of the right
side inlet valve. Fig. C9 shows the point where
the feeler gauge is inserted.
5 If the clearance is correct i.e. the feeler gauge just
nips, proceed to check the next valve as in (7). If
gauge will not enter or if it does not nip, adjust as
in (6).
6 Referring to Fig. C9, slacken the adjuster locknut
(A) and screw out the adjuster (B) two turns.
Place the feeler gauge between the adjuster and
end of the valve stem and screw the adjuster in
Fig. C10
Support connecting rods to prevent damage against
crankcases
Engine/Primary Transmission
2 Commence lifting the cylinder off the base studs
and prepare to support the connecting rods as the
cylinder is lifted clear of the pistons. In Fig. C10 a
suitable implement has been inserted between the
refitted cylinder through bolts to prevent the
connecting rods and pistons falling against the
crankcase mouth. Any damage to the connecting
rods could result in failure of the rods at a later
stage of use.
3 Place a piece of clean non-fluffy cloth over the
crankcase mouth to prevent foreign matter entering
the crankcase mouth.
4 Remove one circlip from each wrist pin (gudgeon
pin).
5 Before removing the piston, support the body
(Fig. C11) shows the piston body being supported
by a second operative) and push out the first wrist
(gudgeon) pin, then the second, using a suitable
sized implement such as an aluminium drift.
N2
Fig. C11 Supporting piston body whilst pushing out
gudgeon pin
SECTION C12
CYLINDER REBORING AND OVERSIZE
PISTONS
After considerable mileages, or on engines where air
filtering has been inefficient or oil changes neglected,
wear may be expected on the cylinder bores or pistons.
The maximum degree of wear may be expected to occur
at the top front and rear areas of the cylinder bores.
Similarly, the maximum wear will take place on the front
and rear faces of the pistons. Measure the cylinder bore
diameter front and rear within + in. (12:70 mm) of the
top of each bore and again front and rear at a point in
the bore below the piston ring swept area. If the bores
are in acceptable condition, the difference between the
measurements should not exceed 0-005 in. (-1270
mm).
An alternative (but less accurate) method of measure-
ment is to place one compression ring in the bore,
approximately + in. (12:70 mm) from the top and
measure the ring gap with feeler gauges. Place the ring
lower in the bore below the piston ring swept area and
again measure the gap. Subtract the second reading
from the first and divide by three to arrive at the
diameter wear. The amount of wear should not exceed
0-005 in. (-1270 mm).
Excessive wear will necessitate reboring and the fitting
of oversize pistons which are available in oversizes of
+ 0-010 in. and + 0-020 in. Bore measurements are
listed below :
STANDARD:
+010 in. oversize
+-020 in. oversize
3-032 in. (77-013 mm)
3-042 in. (77-267 mm)
3-052 in. (77-521 mm)
Wedging of rear brake
Fig. C12
SECTION C13
REMOVING PRIMARY CHAINCASE
То Гетбуе the engine or gearbox from the mounting
plates or from the frame it is necessary to dismantle the
Engine/Primary Transmission С
primary transmission completely but the engine/gearbox -
transmission assembly can be removed from the
frame as a single unit.
Dismantle the outer primary chaincase as follows:
1
Depress the gear-shift pedal and engage low gear.
and disconnect the electric starter terminal.
Wedge a large screw-driver, rod or similar over the
brake pedal pad, under the footrest rubber and
hook the end under the kick-start pedal to ‘lock-on’
the rear brake and prevent the transmission
turning, as shown in Fig. C12.
Remove the two 1” A/F nuts and bolt from the
L.H. footrest mounting flange noting the rear bolt
also locates the red earth-wire terminal from the
zener-diode.
Place a large drain-tray under the primary cover,
preferably long enough to extend the full length.
Remove drain plug below alternator bulge in
cover and allow oil to drain.
Remove the eleven posidrive screws securing the
chaincase and noting the one long screw which
passes through the inner cover and locates the
electric starter. The joint may need a few gentle
blows with a hide or rubber mallet to break the
seal on the paper washer and dowels. As the seal
breaks watch out for residual oil which will now
fall into your tray if the cover was not fully
drained. The outer cover now lifts clear complete
with foot-shift pedal which disengages from the
cross-shaft pinion, leaving the machine in low
gear in readiness for onward dismantling.
Fig. C12 (a) Removing rotor nut whilst applying rear brake to
prevent movement
Withdraw the gear-shift cross-shaft from its
splined connector with rubber sleeve on the
opposite side of the machine leaving the pinion
and circlips in situ on the shaft.
SECTION C14
DISMANTLING PRIMARY TRANSMISSION
AND CLUTCH
With the rear brake pedal wedged on as C13 (2)
Proceed as follows:
1
Using a suitable sized socket wrench 4 in. Whit. on
the alternator rotor nut, remove the rotor nut as
shown in Fig. C12.(a)
As the rotor nut is removed, collect the fan disc
washer from behind.
Remove the alternator stator. This is secured by
three nuts and plain washers. As the stator is
removed, it may be left hanging on the stator lead
whilst the two snap connector terminals are dis-
connected beneath the air box.
At this stage remove the alternator rotor which is
keyed to the engine crankshaft. If the rotor should
prove to be extremely tight on the engine crank-
. shaft, slight pressure may be applied from behind
“equally, using two flat section tyre levers. Remove
the rotor key packing collar and shims from the
engine shaft.
Bend back the locking tabs on the four 3” A/F
nuts securing the alteriator outrigger plate and
remove nuts and washers. The mounting will now
lift off, revealing the large dia. reduction gear
which engages in the sprag mechanism (housed
in the engine sprocket), and runs on its own
needle bearing which is mounted on a hardened
sleeve pinched between the rotor spacer and
backing washer in the sprocket recess. Lift off the
gear, withdrawing sprag roller-cage complete; the
hardened sleeve and the backing washer, revealing
the two tappings provided for the sprocket-
extractor, as on previous models. (N.B. Longer
extractor screws are necessary with the Mk III
mainshafts).
Engine/Primary Transmission C
10
11
я.
el
Remove the starter-intermediate gear shaft com-
plete with back-fire “overload” device, withdraw-
ing its shaft spline from engagement in the large
gear at the back of the inner-cover. The over-load
clutch mechanism remains undisturbed as set at
the factory and should require no attention. Its 3
disc-springs will hold the driving balls in their
detents for starting, but allow slip under shock-
load in the unlikely event of a backfire.
Remove the small nut in the Primary Chain
Tensioner followed by the .two 1” A/F nuts
releasing the steel outer-plate and allowing the
tensioner assembly to lift off its studs. To avoid
interchanging plungers in opposite bores the
assembly relationship should be marked e.g. with
indelible pencil or similar, and the plungers taped
or wired in position to obviate mixing the fits,
avoiding the need for re-priming the dashpot on
re-assembly. Cleanliness is essential for efficient
operation and on no account must the nuts be
over tightened on re-assembly. The tensioner is
fully automatic, the oil dashpot taking up adjust-
ment as required. This refinement permits a
rigidly mounted gearbox and allows the gearshift
to be transferred to the left hand side of the
machine on the Mk IH! model. with a minimum of
complication.
Slacken the clutch push rod adjuster nut and
remove the adjuster and nut together.
In order to dismantle the clutch, a compressor tool
part number 060999 is needed for the diaphragm
spring of the clutch. The tool is shown in use in
Fig. C13. Note that the tool has been screwed into
the adjuster hole in the spring centre. The centre
bolt must be lightly tightened and must be at least
% in, engaged into the diaphragm spring centre.
Now place a spanner on the withdrawal nut as
shown in Fig. C13. Turning clockwise will tighten
the withdrawal nut until pressure has besn
released from the diaphragm spring and the spring
completely free to rotate
When the spring is compressed and free to rotate
and using ascrewdriver blade as shown in Fig. C14,
lift the first end of the diaphragm spring clear of
the circlip groove in the housing and commence
to peel the circlip away from the groove.
The compressor tool and diaphragm spring should
now be lifted clear as a pair.
St. is not necessary to remove the tool from the dia-
wh
,-
phtagm spring. If it is desired to remove the tool from the
diaphragm spring, support the centre bolt to prevent it
turning and slacken off the withdrawal nut to relieve all
spring pressure. If this is not done there is a grave risk
of the spring being released suddenly from the tool
with possible injury.
Fig. C13 Diaphragm spring compressor too! 060999 in use
12
13
14
15
Fit clutch tool 061015 over hub and remove the
clutch centre nut and tab washer. Alternatively the
clutch can be held by wedging the rear brake
(as C13.2) while the nut is slackened.
Prepare to remove the engine sprocket, primary
chain and remainder of the clutch as a set., This
necessitates the use of engine sprocket u
part number 064297 assembled to the glibc
and engine crankshaft as shown in Fgh
It is essential that the side bolts are screwed into
the sprocket at least + in. prior to tightening of the
centre bolt for extraction putposes for otherwise
the thread may be stripped. Now tighten the
centre bolt of the puller against the crankshaft and
shock the side of the sprocket using a soft metal
drift and hammer, whereupon the taper joint :
between the sprocket and shaft should be broken.
For convenience, remove the engine sprocket
puller from the sprocket and lift away the remainder
of the clutch, the engine sprocket and primary chain
as a set as shown in Fig. C16, feeding the stator
between the runs of the primary chain.
It will be noted that clutch and engine sprocket
alignment has been ensured by the use of a collar
— Engine/Primary Transmission
and spacers over the gearbox mainshaft and these
items should be collected and stored carefully for
use during re-assembly. Note that if the crank-
shaft, engine sprocket, mainshaft or clutch have
been renewed, re-alignment may be necessary.
16 The inner primary cover can now be removed as
follows: First ensure the clutch adjustment
circlip is removed from the gearbox mainshaft and
PF,
La
- и
ines
dh SE a
FE +
LA
Yer
. TR
„7
Fig. C14 Using a screwdriver blade to peel circlip away from
housing
Use of engine sprocket puller 064297
Fig. C15
SECTION C15
the internal fixing nut detached from the central
boss.
The inner cover can now be lifted off its studs with
or without the stator which is merely retained by
its cable passing through the grommet.
The electric starter may remain attached if desired.
Fig. C16 Removing engine sprocket clutch and primary chain
as a set
REMOVING CRANKCASE ASSEMBLY FROM
FRAME
Removal of the crankcase assembly from the frame is
most easily achieved by removing the remaining
ancillary equipment then taking out the front mounting
complete and draining all remaining oil from the
crankcase.
The full routine is as follows:
1 Disconnect the tachometer cable at the front of
crankcase.
2 Remove the rocker feed pipe from the back of the
crankcases and collect the copper washers.
3 Remove the gear indicator warning light wire at
snap connector.
4 Slacken jubilee clip and detach breather pipe at
timing cover.
b Place a large capacity drain tray beneath the
crankcases.
, Engine/Primary Transmission C
10
Fig. C17
Remove the oil pipe junction block from the rear
of the crankcase. |
Slacken the large hexagon sump filter on the
bottom of the crankcases. This filter requires the
use of a § in. Whit. (or 13 in. AF) spanner.
Service tool NM 12093 is suitable.
Remove the large diameter centre bolt of the front
mounting from the timing side. This will necessi-
tate aligning the flats on the bolt head to clear the
timing case. The Mark II! isolastic mountings are
now adjustable and the new design permits
dismantling in one piece, with end caps in position.
Remove the two nuts from the timing side of the
engine mounting studs, then pull out the studs
complete with remaining nuts from the drive side.
The front mounting can then be pulled free away
from the crankcases.
Remove the bottom rear crankcase-to-engine-
plate bolt and the bottom centre stud. Extract the
bottom stud by lifting the crankcase assembly
slightly so that the stud clears the frame rails.
The sump filter can now be removed completely
and the engine lifted vertically to enable the
crankcase to be drained. Fig. C17 shows the
crankcases supported by a bar from below whilst
the sump filter is removed with the fingers after
slackening at an earlier stage.
м0
Showing crankcases supported by a bar to remove
sump filter
11
12
Remove the top rear engine to engine plate nut,
supporting the weight of the crankcase as the stud
is pulled out. |
The crankcase assembly is now free to be removed
from the mounting plates as shown in Fig. C18.
Further dismantling of the engine can proceed
more conveniently on the bench after removal.
Fig. C18
Removal of the crankcase assembly from mounting
plates
SECTION C16 |
DISMANTLING THE CRANKCASES
The majority of the work on the crankcases can be
carried out best with the crankcase mounted in a plain
Fig. C19
jaw vice as shown in Fig. C19.
—
Showing crankcases mounted in a plain jaw vice for
ease of handling
e Engine/Primary Transmission Ç
The basic order of dismantling is to remove the timing
cover and dismantle the camshaft chain and sprockets,
then the oil pump. At this stage the crankcases should
be removed from the vice to be parted for removal of
the crankshaft. The full routine is described below :
1 If the remaining crankcase bottom bolt is still
fitted, this should be removed to allow the crank-
case to be mounted securely in a vice.
2 Remove the two contact breaker cover screws and
lift away the C.B. cover.
3 Remove the contact breaker cam centre bolt,
serrated washer and plain washer.
Using service tool 064298 as shown in Fig. C20,
screw the shaft into the contact breaker cam then
slide the weight back sharply several times until
the cam is lifted off the camshaft taper. It is
unnecessary to remove the contact breaker plate
from the timing cover at this stage unless so
desired.
5 Remove the timing cover screws and part the
joint between the timing cover and crankcase by
a careful tap from behind the pressure release
valve body using a hide hammer.
6 Lift the timing cover away, withdrawing the
contact breaker lead from the timing case. It may
be necessary to turn one of the snap connector
builets backwards so that the lead feeds through
the case, one snap connector bullet at a time.
Fig. C20 Removing contact breaker cam using slide hammer
© 064298.
As the timing cover leaves the pump the new
plunger at the conical rubber seal should be
collected with its spring. This device is new on the
Mark Ill and is designed to cut-off the flow of oil
when the engine stops, preventing seepage past
the pump and the possibility of oil building up in
the crankcase during storage. (See Fig. C30 for
illustration).
The inclusion of this anti-leak valve has intro-
duced an important requirement on INITIAL
RUNS of the Mark lll model.
It is essential to prime the oil pump, and oil feed
pipe before running the engine. See section C.30
for method. See Fig. C30 for illustration of valve.
Remove the two nuts securing the oil pump. The
oil pump may be quite tight on its studs and in
these circumstances it is advantageous to turn the
oil pump drive wheel nut so that the oil pump
will pull itself away along the worm drive. This
operation is shown in Fig. C21.
Fig. C21 Using a spanner to turn the oil pump drive wheel nut
and remove the pump
Remove the oil pump driving worm from the
crankshaft with its integral left hand threaded nut.
To achieve this it is necessary to stop the crank-
shaft turning in the cases either by passing a round
bar through the small ends and supporting on
clean wooden blocks across the crankcase mouth
or by placing a suitable bar into the deepest
balance hole and allowing the bar to abut against
the crankcase mouth in a similar manner to that
shown in Fig. C22.
1
!
\
Fig. C22 Preventing flywheel turning by use of a bar lodged in
9
10
11
12
a flywheel balance hole
With the flywheel still prevented from turning,
remove the nut securing the camshaft sprocket.
Under no circumstances must anything but firm
steady pressure be applied to unscrew the cam-
shaft sprocket nut — normal right hand thread —
unless a dummy cut away timing cover is fitted and
secured with screws at extreme front rear and
bottom. If a hammer or mallet is used without such
a cover to support the end of the intermediate gear
spindle, there is risk of the latter being pulled out
of the crankcase.
The size of the sprocket nut is 77 in. Whitworth.
Lift the sprocket, idler gear, and timing chain away
as a set. If the camshaft sprocket should prove to
be tight on the camshaft, it may be removed by
using the special jaws supplied with the 064297
engine sprocket extractor.
Do not remove camshaft key from camshaft
except for replacement.
Providing the timing cover joint gasket is not
damaged during dismantling, there is no reason
why it should be removed from the crankcase
facing as it will be perfectly suitable for re-use.
Using Service Tool ET.2003 as shown in Fig. C24,
extract the crankshaft pinion. It should be noted
that the jaws of the service tool locate to the
spaces provided in the pinion backing washer.
Fig. C23 Releasing a tight camshaft using sprocket service tool 064297
13
14
15
Lift away the pinion key which is of the Woodruff
type. Remove also the backing washer.
Remove the oil sealing disc which is lipped. This
disc tends to cling to the main bearing due to the
presence of oil and the use of two smail magnets
or some other means is recommended to lift the
disc clear. | -
If desired, the timing chain tensioner, clamping
plates, nuts and fan disc washers can be removed
from the crankcase at this stage.
Fig. C24 Extracting crankshaft pinion using tool ET 2003
Engine/Primary Transmission C
16 Dismount the crankcases from the vice so that
they may be parted and the crankshaft assembly
extracted.
17 Remove .the two studs, one bolt and two set
screws, holding the crankcases together. Unless
the additional bottom stud has been removed to
mount the crankcases in a vice, the stud should be
removed at this stage.
18 Part the crankcases, releasing the crankcase joint
by the use of bar of wood against the drive side
crankcase as shown in Fig. C25.
Fig. C25 Parting the crankcases using a wood block against the
inner drive side
19 Withdraw the camshaft from the timing crankcase
and collect the chamfered thrust washer.
20 The Mark ill is equipped with two roller bearings
and the timing side crankcase should now lift off
without difficulty.
SECTION C17
CRANKCASE OVERHAUL
The following text covers the renewal of main bearings
only. In our experience the camshaft bushes have an
extremely long life and renewal cannot be accom-
plished without extensive machining facilities. To
remove the main bearings, it is necessary to heat the area
surrounding each main bearing with a soft flame such
as a gasoline or kerosene (petrol or paraffin) blow
lamp or butane or propane. Concentrate the heat in the
area of the crankcase surrounding the main bearing and
by bumping the joint facing of the crankcase hard
- against a flat wooden surface, the main bearing outer
Engine/Primary Transmission €
race should be dislodged. In the case of drive side
heated, in the case of a timing side crankcase equipped
with the ball type of main bearing, use a suitable soft
drift against the inner race of the main bearing and the
bearing can be drifted out. In the case of a timing side
crankcase equipped with the roller type of main bear-
ing, heat the area of the crankcase surrounding the main
bearing and by bumping the joint facing of the cankcase
hard against a flat wooden surface, the main bearing
outer race should be dislodged. In the case of drive side
crankcases, the complete crankcase will need to be
appreciably hotter since the only method of removing
the main bearing outer race will be to bump the crank-
case sharply against a flat wooden surface.
To refit the main bearings, the cases must be similarly
heated and the main bearings, whether of the ball or
roller variety should drop, completely freely, into their
housings. The main bearings must be fully home into
the housings both at the drive side and timing side
cases.
SECTION C18
REMOVING CONNECTING RODS
Remove the connecting rods by releasing the two self
locking nuts when it should be possible to pull the
connecting rod away from the cap by hand pressure.
The bearing shells remain in position at this stage but if
they are to be re-used, they must be protected from dirt
and possible damage. It is vitally important that at no
stage are the connecting rod end caps interchanged
between rods and it is equally important that the end
caps should not be reversed on their own connecting
rods.
A scribe marking is used on the connecting rod and end
cap to show the correct direction of fitting. The locating
tabs on both of the bearing shells fit to the same side
of each connecting rod.
SECTION C19
DISMANTLING THE CRANKSHAFT
The Mark Ill crankshaft is of stiffer construction than
previous assemblies, the webs are thicker and the main
bearings have been spread to accommodate the wider
cheeks. The drive side oil-seal is also retained by a
circlip on the new engine. The drive side mainshaft is
extended to accommodate the electric starter mech-
anism,
Engine/Primary Transmission C
The flywheel clamping studs have been increased from
+5" to 3” dia. and on early despatches the alignment
was dowelled by one %”/3” dia. shouldered stud on
the crank centre line and one each 3” dia. fitted stud at
11 o'clock and 1 o'clock respectively. The remaining
four studs were a clearance fit.
On final production the arrangement has been rational-
ised to use a common stud. The shouldered stud has
been replaced by a further 3” dia. stud in common with
the fitted studs at 11 oclock and 1 o'clock. The
remaining four studs are clearance. The fit is obtained
by varying the hole sizes only. See section C27
illustration C33.
It is to be expected that the crankshait assembly which
is now to be stripped will contain approximately one
teacup full of oil and provision should be made for
collecting this oil in a suitable receptacle.
Before parting the crank cheeks from the flywheel, itis
recommended that the flywheel be marked e.g. “7.5.”
for timing side so that it is not reversed during re-
assembly. Proceed as follows:
1 Slacken the fixed nuts on the timing side securing
the crank cheek to the flywheel, noting that the
nuts have been ‘loctited’ during assembly and may
be expected to be extremely tight.
2 Jar the crank cheeks free from the flywheel using
a hammer and soft drift. The drive side crankshaft
will come away.
Dependent upon mileage there is likely to be a con-
siderable build up of sludge and foreign matter in both
the crank cheeks and the recess in the flywheel. This
foreign matter must be cleaned out most thoroughly.
Tool No. 063970 is available to remove roller bearing
races from the crankshaft, as shown in Fig. C28.
SECTION C20
CRANKSHAFT INSPECTION AND
REGRINDING
Wash each crank cheek in clean petrol and blow dry
with an air line. Examine the big end journals for scoring
and remove light score marks by the use of smooth
emery tape. If there is excessive scoring or ovality
and it exceeds 0-:0015 in. (0381 mm) on the big
end journals, regrinding is necessary.
The regrind sizes are shown overleaf. The revised big
end journal sizes necessitate the use of connecting rod
shell bearings of the correct undersize. The steel backed
big end shells are finished to provide the correct
diametrical clearance and must not, under any cir-
cumstances, be scraped. Shell bearings are available
Fig. C28 Removing roller bearing inner race using extractor
063970.
in undersizes of minus 0-010 in., minus 0-020 in.,
minus 0-030 in. and minus 0-040 in.
SECTION C21
ENGINE LUBRICATION SYSTEM
The Commando lubrication system as shown in Fig. C29
is of the dry sump type, oil contained in the separate oil
tank being fed through a wire strainer by gravity and by
suction through the feed side of the gear type oil pump
to the crankshaft. The oil pump delivers lubricant under
pressure to the oil pressure relief valve and a bleed off
the main feed supplies lubricant to the rocker gear. The
main oil supply is delivered through the end of the
crankshaft, (which is sealed by a garter type seal in the
timing cover) to both big ends and escapes between the
big end shells and crank journals to lubricate the
cylinder walls, main bearings, camshaft and cam
followers by splash. Oil collects in the crankcase sump,
the inlet rocker box draining through a drill way in the
cylinder barrel, and the exhaust rocker box draining
through á drill way into the push rod tunnel and
providing additional lubrication whilst returning to the
crankcase between the cam followers to the camshaft.
The return side of the oil pump draws oil from the
sump via the collecting area in the crankcase and
returns it to the oil tank.
N.B. The chain oiler previously used is now discon-
tinued. On the Mark lil an aerosel can of chain-
spray is provided in the tool kit.
Engine/Primary Transmission C
Nr
7405,
1 740091A FIRST RE- GRIND
7 ISS GRIND , THE CRANKPIN TO
| | > 1 1-740571- 7400" DIA. WITH
| > .090" FACE RADIUS,
_
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— - STAMP -.OIO HERE.
.090 RAD.
IMPORTANT
№
117398001,
- SECOND RE-GRIND
7 E GRIND THE CRANKPIN TO
_ 1-7305/1-7300'DIA. WITH
.090 FACE RADIUS.
- — - STAMP --020 HERE.
-O90 RAD.
IMPORTANT.
NS
papa Ш
% THIRD RE-GRIND
a 5 GRIND THE CRANKPIN TO
- . : 1-72057/ 1: 7200 DIA WITH
| .O9O FACE RADIUS.
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- | STAMP -:030 HERE.
:O90 RAD.
IMPORTANT.
| №106
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Fig. C26 Crankshaft big-end journal regrind particulars
Fig C29 Engine lubrication system
— Engine/Primary Transmission C
SECTION C22
OIL PRESSURE RELIEF VALVE
The relief valve is fitted to prevent oil pressure rising
above 45/55 Ibs. sq. inch. It is fitted to the rear of the
timing cover below the rocker oil feed pipe banjo. The
valve consists of a spring loaded steel sleeve pre-set at
the factory using shims to regulate the blow oft
pressure and the valve requires no attention. Oil
escaping from the valve returns to the feed side of the
pump. The Mark Ill design has been modified to
improve flow, reduce aeration and increase pressure at
high temperature.
SECTION C23
CRANKCASE BREATHER
The Mark H! engine has a breather located at the top
rear of the timing chest. As with earlier models, the
breather is vented through the oil tank to the air filter,
but the new model has an additional oil separator
which traps oil passing beyond the breather before it
enters the air-box.
Qil collected in the separator will be sucked into the
engine via the intake balance pipe which now has a
tee-piece junction to accommodate the oil pipe.
SECTION C24
OIL PUMP
The oil pump is of the gear type and is shown in detail
in Fig. C30. The return side of the pump, which is of
twice the capacity of the feed side to provide sufficient
capacity to keep the crankcases clear of surplus oil, is
identified by the wider gears. The oil pump is sealed to
the timing cover bore with a conical rubber oil seal
located on the pump body by a steel ferrule and com-
pressed by the timing cover. An additional cut-off
valve is now a standard feature on the Mark Ill, see
C16 paragraph 6. Removal of the oil pump is included
Fig. C30 Comprising parts of oil pump
in Section C16 and the servicing routine covered in
Section C25.
SECTION C25
SERVICING THE OIL PUMP
Removal of the oil pumpisdescribedin Section C 76. The
criterion of oil pump condition is the degree of end float
on the oil pump pinions, most easily felt by movement
of the oil pump driving gear relative to the pump body.
After some period of use, the tendency is for the
pinions to wear into the pump end covers and such
wear can only be removed by taking off the covers and
flattening down the actual pump body.
1 Detach the pump top covers and drive gear with
drive spindle by tapping the spindles through the
keyed pinion with a pin point drift. The remaining
parts can be lifted from the pump body at this
stage.
2 Wash all the components thoroughly in clean
gasoline (petrol) and allow to dry.
It is most important to correct end float on the feed
gears (the narrow ones) first.
Engine/Primary Transmission (С
3 Remove the feed gears and rub down the back
plate end of the pump body surface against a high
grade quality emery cloth on a perfectly flat
surfacesuch asasmalisurfaceplate. Flattening of the
surface should continue a little at a time until the
stage is reached where, on re-assembly of the oil
pump, there is barely discernible stiffness on the
oil pump driving spindle. This barely discernible
stiffness will indicate that there is just sufficient
freedom of movement and that there is no
excess clearance between the feed gears and
housing.
4 Remove the feed gears and repeat the flattening
down process on the return side of the pump
body until with the return gears only in the pump
body and the screws tight there is similar slight
stiffness.
5 Strip the pump body again and wash with very
great care. Reassemble the pump and tighten the
screws completely. At this stage there should be
some degree of stiffness in the complete pump.
6 Introduce oil into the feed hole then, holding the
oil pump with one hand, place a ring spanner over
the driving spindle nut, and revolve the oil pump
a number of times to allow oil to circulate com-
pletely. The oil pump should now have freed off
considerably. Slight stiffness remaining should
decrease, if not disappear completely.
SECTION C26
TIMING COVER
There are two garter type seals in the timing cover, one
at the contact breaker housing and one to seal the
crankshaft to the cover.
Contact Breaker Seal — Failure of this seal is indi-
cated by the presence of oil in the contact breaker
housing. To remove the old seal it is necessary to prise
out with a screwdriver or similar implement thus
rendering the seal scrap. A new seal should be fitted,
pressure side, that is spring side, towards the engine and
the seal. should be tapped fully home into the housing
using Service Tool 064292.
Crankshaft Seal — This seal is retained in the housing
with a circlip. After removing the circlip, the seal can
be prised out of its housing but will be damaged beyond
further use. Care must be taken to avoid damage to the
housing. Fit the new seal pressure side towards the
timing cover and drive fully home using Service Tool
064292. Refit the circlip “sharp” side towards the
crankcase and make sure that it is fully seated all-
round.
Fig. C31 Showing blanking plug in position in timing cover
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Fig. C32 Positions and lengths of odd timing cover screws
SHORT ~~.
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Where a new timing cover is being prepared for fitting,
check that the blanking plug shown in Fig. C31 is in
position. The timing cover odd screw lengths are
shown in Fig. C32.
— Engine/Primary Transmission
SECTION C27
RE-ASSEMBLY OF THE CRANKSHAFT
Prior to assembly, it is vital to polish the crank journals
using a fine grade emery tape then make absolutely
sure that all parts are washed very thoroughly in
gasoline (petro!) until clean. Ensure also that the oil
ways are clean and blown through with an air line.
Re-assembly proceeds as below :
1 Fit the drive side crank cheek to the flywheel, mat-
ing the markings previously made.
2 Fit the central dowel stud through from drive side
to timing side, check alignment of crank cheeks,
and assemble remaining two dowel studs at 11
o'clock and 1 o'clock respectively.
3 Assemble the timing side crank cheek over the
three studs noting that all three studs are a good
fit in the crank cheeks and will probably need
tapping home with a drift.
4 Assemble the four remaining studs, driving side to
timing side, these are a clearance fit and should
assemble without difficulty.
5 Apply loctite LT. 241 or similar thread locking
compound to all studs and -assemble nuts,
tightening progressively and diagonally to 30
Ibs./ft. torque (4:15 Kgm).
6 Ensure that the oil way blanking plug is fitted in
the timing side crank cheek, particularly if a new
timing side crank cheek is in use.
ALL NUTS NOW 3g =14 OFF
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3 FITTING
STUDS PROVIDE
DOWELLED
LOCATION
SECTION C28
RE-ASSEMBLING CONNECTING RODS
TO CRANKSHAFT
As a matter of practice always use new bearing shells
and at the time of fitting the shells, smear them with
clean engine oil. Proceed as follows :
1 Press the drilled shell into the connecting rod big
end eye and rotate into position, locating with the
tab.
2 Fit the plain shell into the connecting rod cap and
again locate the tab. The tab positions are shown
in Fig. C34.
3 Fit the connecting rods but before doing so, note
that it is unnecessary to renew the connecting rod
bolts though new nuts should always be used.
The connecting rods must be fitted with the oil
holes from the big end eye outwards in each case.
Fit the end caps with shells, ensuring that the
mating marks align, and tighten the nuts evenly
by hand.
4 Tighten the connecting rod nuts to a torque read-
ing of 25 Ibs./ft. (3-456 Kg/m).
Fig. C34 Connecting rods showing both sides of big end eye and
bearing shell tab locations - Mark III now shot-peened
> Fig. C33 Showing crankcheek to flywheel securing hardware for greater fatigue life.
/
—
Engine/Primary Transmission Ç
SECTION C29
RE-ASSEMBLING CRANKSHAFT
TO CRANKCASES
1
Push the timing side crankcase over the crankshaft
which must be supported upright on the bench.
See Fig. C35. At this time check that the connecting
rods clear the crankcase mouth of the crankshaft
end of the bearing. If the bearing is too tight to
push home over the crank, place a scrap main
bearing inner race and a large washer over the
crankshaft, outboard of the timing side crankcase
then, using the oil pump driving worm on the
crankshaft, pull it home through the bearing.
Position the camshaft thrust washer over the
timing side camshaft bush and locate this, flat
side towards the crankcase and bush, locating
with a blob of grease.
Smear the timing side crankcase joint facing with a
non-setting sealing compound. A little may be
applied to the timing side case facing where there
is NO spigot.
Fig. C35 Pushing timing side crankcase over crankshaft
Offer the drive side crankcase to the timing side
after oiling the camshaft bearing area and the drive
side roller main bearing. The operation of mating
the crankcases is shown in Fig. C36. It is most
important that the drive side connecting rod does
not come into contact with the crankcase mouth
and at the final stage of mating the crankcases, it
may well be necessary to turn the tachometer
drive to locate into the camshaft worm drive.
Now tap the crankcases together with a hide
hammer until the joint faces meet all-round.
Before tightening the crankcase securing nuts,
ensure that there is end float on the camshaft,
indicating its freedom.
Fit the crankcase front and rear screws, studs, nuts
and washers.
Fig. C36 Mating crankcases.
8 Fit the short front crankcase mating bolt from drive
side to timing side then fit the front bottom stud
unless the crankcase is to be mounted in the vice
in which case this front bottom stud should be
omitted until a later stage.
9 Fit the two slot headed set screws from the timing
side.
10 Tighten the mating nuts and screws evenly in
rotation and wipe away surplus jointing compound
remaining on the outside of the crankcase joint
facing.
SECTION C30
ASSEMBLING RIGHT (TIMING SIDE)
OF ENGINE
Having assembled the crankcases as detailed in Section
C29, mount the crankcases in a plain jaw vice to
facilitate handling. Re-assembly of the cam chain,
sprockets and oil pump may now be undertaken as
follows:
1 Fit the oil sealing disc over the timing side crank-
shaft, lip outwards.
2 Fit the cut-away backing washer.
3 Fit the woodruff key into the crankshaft then
place on the crankshaft pinion, chamfered teeth
and timing mark outwards. It may be necessary to
tap the pinion fully home using a suitable tube as
a drift.
4 Turn the crankshaft to top dead centre so that the
timing pinion marking is uppermost.
5 Take the intermediate gear sprocket, the camshaft
sprocket and cam chain, assembling as shown in
Fig. C37. For correct timing the timing marks must
be 10 rollers apart on the chain as shown in the
illustration.
6 Locate the camshaft sprocket and intermediate
gear and sprocket in position, mating up the
marked space between the teeth on the inter-
— Engine/Primary Transmission C
Fig. C37 Assembly of timing chain and sprockets. Note arrows
=
mediate gear with the marked tooth on the timing
pinion. On all engines it will be found that there is
a paint marking to illustrate more clearly the timing
position on the intermediate timing gear.
Assemble the chain tensioner as shown in Fig. C38,
The Mark Hl tensioner blade now has a neoprene
covering and the clamp plates (which previously
differed) are common and interchangeable.
Fit the chain tensioner, fan disc washers and nuts
moving the tensioner blade up to give a maximum
“in. (4-8 mm) up and down movement at the
tightest point of the chain and nip up the tensioner
securing nut. Before finally locking up these nuts,
rotate the crankshaft a little at a time, checking at
each stage the chain tension lest there should be
a tight spot on some point of the chain. When
chain tension is correct, finally lock up the ten—
sioner securing nuts.
The Mark IH model has an inspection plug in the
timing cover for checking tension easily in
service without disturbing the cover.
Engine/Primary Transmission Ç
BOS
Nol
Fig. C38 Chain tensioner - assembly
10 Fit the oil pump driving worm which is left hand
threaded.
11 Fit the camshaft sprocket nut which is normal
right hand threaded.
12 In order to tighten both the oil pump driving worm
nut and camshaft sprocket nut securely it is
necessary to sprag the crankshaft with a suitable
bar placed in the deepest of the flywheel balance
holes as shown earlier in Fig. C22.
Under no circumstances tighten the camshaft
sprocket nut by shocking using a box spanner,
tommy bar and hammer since an even pressure is
required specifically for tightening this nut.
Tighten securely the timing pinion nut.
Prior to fitting the oil pump it is desirable, if the pump
has been stripped or parts renewed, to prime this. The
pump should be turned by hand and oil fed into the gears
by the use of an oil gun.
13 Fit the oil pump and secure with two nuts without
washers. A torque figure of 10/12 ft. Ibs. (1-383
to 1:659 Kg/m) is required.
14 Fit a new conical rubber oil seal part number
NMT272 on the oil pump outlet stub.
15 After the ail pump is secured, recheck the security
of the driving gear nut,
SECTION C31
REFITTING THE TIMING COVER
The timing cover should be prepared by washing very
thoroughly in clean gasoline (petrol) and if necessary
by renewing the oil seals as described in Section C26.
If a new timing cover is to be fitted, check that the
blanking plug is fitted into the boss for the pressure
relief valve. This feature is shown in Fig. C37.
1 Fit the contact breaker oil seal protection tool
061359 into the camshaft and tighten. This will
allow the contact breaker seal to pass over the
camshaft without damage as the timing cover is
placed in position. Lightly oil the tapered surface
of this tool.
2 Pass the contact breaker lead through the hole in
the timing case, then locate the cover in position,
making sure the cut-off valve plunger and spring
are fitted and the plunger is seating on the conical
rubber. See C16 paragraph 6.
3 Fit the timing cover screws. The odd screw
lengths are shown in Fig. C32 but the remaining
screws are all of the same length. Secure the set
of screws.
4 Remove the contact breaker seal tool 061359.
5 Prepare the auto advance mechanism by cleaning
very thoroughly and lubricating sparingly with
clean engine oil. Ensure that the taper for the auto
advance cam is clean and dry then offer the auto
advance unit loosely into position.
6 Fit the contact breaker plate, yellow lead rear-
wards and secure with the pillar studs central in
the adjustment slots. For ease of handling at a
later stage, centralise both contact breaker plate
adjusters. These are indicated in Fig. C54.
SECTION C32
RE-ASSEMBLY OF CRANKCASE
ASSEMBLY TO FRAME
Re-dssembly of the crankcase into the frame is virtually
a reversal of the dismantling procedure though the
Pa
Nu
7
Engine/Primary Transmission Ç
operation of fitting the front mounting is given com-
plete as below :
1 With the crankcase attached to the rear engine
mounting plates, lift the crankcase assembly and
gearbox, pivoting on the rear mounting to insert
the bottom studs.
It is necessary to fit the front mounting at this stage
before final tightening of all the engine plate to crank-
case bolts and before fitting the inner chaincase.
Adjustment of the front mounting has already been
carried out on the bench as in Section F15.
The Mark 11! isolastic mountings have been re-designed
with one fixed end-cap and one adjustable cap which
is threaded to the central hollow spindle creating an
integral assembly with no loose fittings and allowing
easy adjustment and simple assembly as one unit.
Fig. C39 Lifting front mounting into position using bottom bolt
as pivot
2 Take the front mounting and slide the bottom
mounting to crankcase stud into position.
3 Using the bottom stud as the pivot, lift the mount-
ing into position on the crankcase bosses as in
Fig. C39.
Grease both end cap faces to facilitate insertion
between the mounting ears on the frame.
Lifting the crankcase a little as required to align
the hollow spindle with the frame ears, insert the
centre bolt from the timing side through to the
left hand side, easing the threads carefully past
the ear, avoiding damage to the threads, and
slide fully home.
Ensure that gaiters are not disarranged, revolving
a little to facilitate the operation.
Fit and secure the centre bolt nut and washer and
tighten to 25 lbs./ft. (3:456 Kg/m).
The remaining items of the engine plates which
have been assembled as a reversal of the dismant-
ling procedure should now be tightened to the
recommended torque settings. The 3 in. diameter
engine to frame stud nuts require a torque figure
of 30 Ibs./ft. (4:148 Kg/m) and the % in. nuts to
20 lIbs./ft. (2-765 Kg/m).
As previously mentioned in C16 paragraph 6, the
Mark lll engine is equipped with a new anti-leak
valve between the pump and timing cover oil-way.
This makes it essential to prime the pump and
feed-pipe before running the engine — although
the pump unit has been primed before installation.
The recommended procedure (ref. Engineering
instruction No. 18).
1 Fill oil tank.
2 Slacken junction block screw.
3 When oil escapes from junction block/crankcase
joint retighten junction block screw to 8 Ibs./ft.
(1-10 Kg/m).
The oil pump and feed pipe are now primed.
Engine/Primary Transmission C
Fig. C41
Priming crankshaft with oil
Also prior to fitting the bottom connection for the rocker
feed pipe it is most desirable to prime the crankshaft
with approximately a teacup full of oil. This is most
easily achieved by the use of an oil syringe, short length
of flexible pipe, and a spare rocker feed pipe banjo
which can be connected at the rear of the timing case
The priming operation is shown in Fig. C41.
SECTION C33
REFITTING PISTONS AND CYLINDER
Throughout the fitting of the ‘pistons and cylinder,
take care to protect the connecting rods and pistons
from damage caused by these parts coming into contact
with the crankcase mouth or cylinder base studs.
Proceed as follows"
10
Grease the crankcase studs lightly and apply a coat
of Loctite “plastic gasket” material to cylinder base
flange.
Fit one circlip to each piston, sharp edge out-
wards.
Heat the pistons in hot water to ease entry of the
wrist pins (gudgeon pins).
Oil the small end eye and wrist pin bosses and
push each wrist pin home by hand.
As each piston is fitted, fit the second circlip sharp
end outwards.
Turn the engine crankshaft backwards to lower the
pistons, then support the pistons as in Fig. C42 on
two suitable bars which must not overlap the
timing case.
Position the piston rings with the top compression
ring gap central at the front of the piston body and
the second taper ring gap central at the rear of
the piston body.
Position the scraper ring expander to the side of
the piston body with the rail gap 1 in. to the left
and right of the expander gap to prevent the rail
ends spragging in the connecting rod clearance
cutaways in the cylinders.
Smear both piston bodies with clean engine oil.
Fit piston ring clamps (also shown in Fig. C42)
to keep the piston rings closed. Do not over-
tighten the ring clamps which would tend to
prevent the ring clamps sliding as the cylinder is
offered.
Engine/Primary Transmission C
& 240 in 1b/20 ft Ib (2:75 Kg/m)
360 in 1b/30 ft Ib (4-15 Kg/m)
@ 300 in 1b/25 ft Ib (3-75 Kg/m)
Fig. C42 Fitting cylinder over pistons. Note piston supporting
bars and ring clamps in use Fig. C43 Cylinder base securing torques.
11 Offer the cylinder over the pistons as shown in
Fig. C42, pushing the cylinder down to slide the
ring clamps down quickly. The pistons are now
entered in the cylinder bores.
primary chain, rotor and stator and finally the outer
primary chaincase. The full routine is detailed below :
1 Check that the engine sprocket key will pass freely
12 Remove the support bars and both rings clamps. through the keyway in the sprocket and if neces-
sary relieve any roughness.
13 Partially lower the cylinder but start cylinder base
nuts before lowering the barrel completely. Only 2 Fit the engine sprocket key into the crankshaft.
the large centre nut lacks a washer. The outside
socket head screws all have washers. 3 Fitthe inner chaincase to crankcase gasket, holding
in position with grease or a non-setting jointing
14 Tighten the cylinder fixings in diagonal sequence compound.
working to torque settings as shown in Fig. C43.
4 Check that the plain washer is on the chaincase
support stud.
5 Ensure that the inner and outer joint faces of the
inner chaincase are clean.
SECTION C34
| 6 Fit the inner chaincase, ensuring that the gearbox
ASSEMBLING PRIMARY TRANSMISSION mainshaft seal passes over the mainshaft without
The primary transmission is assembled in the order: damage (covering the splines with plastic tape
inner primary chaincase, engine sprocket, clutch and will help) and that the chaincase forward end is
Engine/Primary Transmission C
fully home on the four long studs which extend
through for the new outrigger mounting plate
supporting the aiternator.
Make sure the central adjustable support stud is
fitted behind the cover with the abutment nut
slackened off, in readiness for adjustment after the
outrigger nuts are tightened. (See Fig. C45)
The electric starter may still be attached by its two
upper fixing screws also the small intermediate
gear which assembles from the back.
At this point it is most important to observe a
fundamental difference between the Mark 1! and
previous Commando models: namely the rigidly
mounted gearbox. (See note 7 Section C14).
It is important that the gearbox sprocket sleeve
runs truly concentrically within the chaincase oil-
seal, which is located inboard at the back of the
cover, behind the clutch. The seal will cope with
moderate misalignment but its function and life
will benefit from extra care in ensuring that the
sprocket sleeve is coaxial with the seal before
clamping up the gearbox mountings. A guide tool
No. ST4928D is recommended to prevent damage
to the seal as it passes over the clutch circlip and
sharp edge of the sleeve. Dimensions and partic-
ulars are illustrated on Fig. C45.
Providing the seal is coaxial, Clamp up the gearbox
mountings and proceed.
Assemble the clutch location circlip and spacer,
recessed portion towards the gearbox, followed
by the spacing washer. The purpose of the spacing
washers is to align accurately the clutch sprocket
with the engine sprocket.
It is always desirable to check chain alignment in
case a collar is forgotten or something has been
changed: Push engine sprocket full home on its
taper over the woodruff key and push the clutch
sprocket firmly over the splines to its abutment-
collar. Check alignment with a steel rule or
similar straight-edge laid along the teeth of both
sprockets. See illustration C.46: Providing nothing
has been replaced the alignment should be
correct and chain fitting can proceed. (Misalign-
ment will need correcting with suitable spacing
washers behind the clutch).
Fig. C45
11
12
13
14
Assemble the engine sprocket and clutch sprocket
to the triple row chain ready for fitting.
With the large starter gear located in the machined
recess behind the top run of the primary chain —
offer the engine sprocket, clutch sprocket and
primary chain as a set, feeding the stator through
between the chain runs. The stator is still attached
to the inner chaincase by the lead passing through
the chaincase grommet.
Local view of Internal Fixing Stud
7 HF = 1875" | 0015 rer
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Details of Assembly Sleeve
Installation of inner primary cover
At this stage push the engine sprocket fully home
over the woodruff key, if necessary using a tubular
drift to push the sprocket fully home. At the same
time the clutch will need to be pushed home firmly
over the splines of the mainshaft.
Fit the clutch centre securing nut and tab washer
engaging the ends in the 2 holes in the clutch
centre.
Wedge-on the rear brake as described in Section
C.13 paragraph 2 to lock transmission and
tighten the clutch centre nut. 061015: workshop
tool for clutch lock is available providing the best
method of assembling the clutch centre. See
service tool catalogue for illustration and partic-
ulars. The correct torque for the clutch centre
nut is 70 Ibs./ft. (9-678 Kg/m). Squeeze the
centre portion of the tab washer to 2 flats on the
nut. Proceed to assemble the clutch.
If for any reason the clutch plates have been
removed from the housing, re-assemble these, an
inner splined friction plate first into the housing,
followed by a plain steel alternately, finishing with
the robust iron pressure plate next to the diaphragm
spring.
Engine/Primary Transmission €
15 The clutch diaphragm spring should be assembled
to the spring tool and tensioned as shown earlier
in Fig. C13 until the diaphragm spring is flat.
Offer the diaphragm spring on the tool to the clutch
housing and push home as far as possible.
Enter one end of the clutch spring circlip and con-
tinue to wind the remainder of the spring into the
housing. |
Fig. C46 Primary chain alignment check
18
19
20
When the spring circlip is well bedded into the
housing all-round, remove the spring tool by
slackening the centre bolt.
Fit the clutch push rod adjuster screw and lock
nut.
Adjust the clutch push rod with the handlebar
adjustment slackened off completely. Screw in the
adjuster until there is just perceptible lift on the
diaphragm spring and slacken back one full turn,
holding in this position whilst the lock nut is
tightened completely.
It is possible for the clutch operating lever in the
kickstart case to have dropped down between the
thrust ball and roller against which the lever lifts
and if this has occurred, it will be found that the
clutch is inoperative, and it will be necessary to
remove the inspection cover which is secured by
two screws to the gearbox outer cover, slacken
back fully the push rod adjuster and lift the lever
back into position before adjusting.
21
22
23
24
25
26
27
Proceed to assemble the starter drive mechanism
as follows:
Replace thrust-collar in sprocket recess — this must
be fitted with small dia. facing outwards.
Fit hardened sleeve on engine mainshaft (this is
likely to be a good fit).
Assemble starter free-wheel sprag into sprocket
recess. It is important to fit this the correct way to
take the starter drive. See ///ustration Fig. C48.
The drive sprag is designed to fling clear as the
engine revs increase, releasing the drive auto-
matically as the motor starts up.
Fit the large starter gear with its needle roller
bearing over the hardened sleeve and enter it into
the roller-sprag. Revolve the gear to check that
the sprag is driving the right way to start the
engine.
Assemble the primary chain Tensioner, (previously
taped or wired to prevent the skate plungers from
springing out of their respective cylinders), replac-
ing the body over its three studs and with the
outer plate located in position assemble the two
+ in. nuts and single 1 in. nut using Loctite
or a thread locking compound such as LT 241
on threads, torquing to 12 Ibs./ft. on the former
and +5 /bs./ft. only on the small nut. These
torque figures are critical.
The tightening procedure is most important and
on no account should the nuts be over tightened
as distortion can occur and jamming may result.
Although priming of the dash-pot should be
unnecessary if the plungers were left in position,
it is desirable to apply a small amount of engine
oil into the catchment and squeeze the plungers to
suck oil into the dash-pot. This will operate
automatically in use. (See Fig. C47).
The over-load backfire device can now be engaged
into the spline of the large gear at the back of the
cover and its outer gear meshed with the sprag-
gear in the engine sprocket. The starter reduction
gear train is now complete. (See Fig. C48).
Engine/Primary Transmission C
15 The clutch diaphragm spring should be assembled
to the spring tool and tensioned as shown earlier
in Fig. C13 until the diaphragm spring is flat.
Offer the diaphragm spring on the tool to the clutch
housing and push home as far as possible.
Enter one end of the clutch spring circlip and con-
tinue to wind the remainder of the spring into the
housing.
Fig. C46 Primary chain alignment check
18
19
20
When the spring circlip is well bedded into the
housing all-round, remove the spring tool by
slackening the centre bolt.
Fit the clutch push rod adjuster screw and lock
nut.
Adjust the clutch push rod with the handlebar
adjustment slackened off completely. Screw in the
adjuster until there is just perceptible lift on the
diaphragm spring and slacken back one full turn,
holding in this position whilst the lock nut is
tightened completely.
It is possible for the clutch operating lever in the
kickstart case to have dropped down between the
thrust ball and roller against which the lever lifts
and if this has occurred, it will be found that the
clutch is inoperative, and it will be necessary to
remove the inspection cover which Is secured by
two screws to the gearbox outer cover, slacken
back fully the push rod adjuster and lift the lever
back into position before adjusting.
21
22
23
24
25
26
27
Proceed to assemble the starter drive mechanism
as follows:
Replace thrust-collar in sprocket recess — this must
be fitted with small dia. facing outwards.
Fit hardened sleeve on engine mainshaft (this is
likely to be a good fit).
Assemble starter free-wheel sprag into sprocket
recess. It is important to fit this the correct way to
take the starter drive. See illustration Fig. C48.
The drive sprag is designed to fling clear as. the
engine revs increase, releasing the drive auto-
matically as the motor starts up.
Fit the large starter gear with its needle roller
bearing over the hardened sleeve and enter it into
the roller-sprag. Revolve the gear to check that
the sprag is driving the right way to start the
engine.
Assemble the primary chain Tensioner, (previously
taped or wired to prevent the skate plungers from
springing out of their respactive cylinders), replac-
ing the body over its three studs and with the
outer plate located in position assemble the two
Ts in. nuts and single } in. nut using Loctite
or a thread locking compound such as LT 241
on threads, torquing to 12 Ibs./ft. on the former
and 4-5 /bs./ft. only on the small nut. These
torque figures are critical.
The tightening procedure is most important and
on no account should the nuts be over tightened
as distortion can occur and jamming may result.
Although priming of the dash-pot should be
unnecessary if the plungers were left in position,
it is desirable to apply a small amount of engine
oil into the catchment and squeeze the plungers to
suck oil into the dash-pot. This will operate
automatically in use. (See Fig. C47).
The over-load backfire device can now be engaged
into the spline of the large gear at the back of the
cover and its outer gear meshed with the sprag-
gear in the engine sprocket. The starter reduction
gear train is now complete. (See Fig. C48).
_ Engine/Primary Transmission Ç
an
SPROCKET
DRIVEN ROTATION
Fig. C48 Starter freewheel-sprag showing diagrammatic view into
sprocket at ‘A’ with sprags leaning at correct angle for drive.
35 Replace the gearshift cross-shaft through its oil-
seal in the inner cover, locating it in the splined
connector on the gearbox replace the protective
rubber sleeve. The pinion and circlip are still in
situ; the shaft wil lengage in the bush in the outer
cover and lie at a slight angle to clear the clutch
chainwheel.
36 Offer up the outer cover, engaging the foot-shift
gear and cross-shaft pinion with the pedal in
desired position, and ensuring the joint washer is
intact, assemble the eleven posidrive screws, the
long screw securing the electric starter.
37 In order that the point is not overlooked it is
recommended that lubricant is added to the
chaincase at this stage.
38 Refit L.H. footrest with red earth wire terminal
from zenor.diode on rear bolt.
Fig. C49 General view of primary drive assembly and chain tensioner:
outer cover removed.
SECTION C35
CLUTCH OPERATING MECHANISM
The clutch is connected from the left handlebar control
to the clutch operating lever within the gearbox cover.
As the lever is withdrawn, the clutch operating lever is
lifted, exerting pressure on a ball bearing against the end
of the clutch push rod. The push rod forces outwards
the centre of the diaphragm spring, relieving the pres-
sure and allowing the clutch plates to separate. For the
clutch to operate correctly, the degree of free movement
on the cable and clutch push rod must be controlled.
Excessive slack may prevent the clutch freeing com-
pletely and excessively tight adjustment will result in
the clutch plates being held apart. Adjustment is pro-
vided on the cable and push rod.
Clutch Adjustment
1 Slacken cable adjustment at the handlebar control
as far as possible.
2 Remove the clutch adjuster inspection cap from
the chaincase.
3 Remove the inspection cap from the gearbox end
cover.
4 With the index finger, move the clutch operating
lever to and fro inside the gearbox cover to estab-
lish whether or not there is slight movement. If
there is, clutch push rod adjustment is correct. If
there is not, rectify as follows.
5 Release nut (B) in Fig. C51 then turn the screw (C)
gently anti-clockwise until movement is felt on the
right side operating lever.
6 Turn screw (C) in a clockwise direction until it is
felt that the screw just touches the push rod.
7 Unscrew adjustment screw (C) one full turn and,
holding in this position retighten locknut (B). This
ensures the correct free movement on the clutch
push rod.
Engine/Primary Transmission C
8 Adjust the clutch cable at the control to provide
Fin. to tin. (4-76 to 6-35 mm) free movement
between the cable outer casing and adjuster.
Fig. C50 Mark II clutch arrangement showing order of assembly
CLUTCH PLATES
The clutch dismantling procedure is covered as part of
Section C13 “Dismantling Primary Transmission and
Clutch.” However, it is sometimes considered necessary
to remove the plates separately for inspection.
To gain access to the clutch plates, follow Section
C13&C14 items 1 to 9. Next remove the clutch pressure
plate followed alternately by the internal splined
friction plates and external splined plain steel plates.
After removal, wash all the clutch plates and the
pressure plate in gasoline (petrol) until perfectly clean,
then allow to dry.
Fig. C51
Clutch adjustment
Reassembly is a reversal of the foregoing but full
instructions are given in Section C34.
Plate Inspection
Examine the friction plates for obvious wear to the
splines and for “charring” of the surface such as would
occur during prolonged clutch slip. Examine the plain
steel driven plates for deep scoring or grooving. Check
the external! splines for obvious wear, and check each
plate in turn on a surface plate for flatness. Any badly
worn or distorted plates must be renewed before
reassembly.
SECTION C36
TACHOMETER DRIVE
The tachometer drive is taken from the worm drive at
the right end of the camshaft. The cable has an adaptor
for the cable between the lower end of the cable and
tachometer driven gear. The driven gear is removable
after removing two screws and lifting clear the housing
and 'O' sealing ring but damage to the drive gear can
only be corrected by replacing the camshaft.
SECTION C37
ELECTRIC STARTER MECHANISM
The Mark lil Electric Starter is permanently engaged
with its reduction gear-train, but only transmits drive
to the engine shaft as permitted by a sprag clutch/free-
wheel which disengages automatically immediately
the engine starts.
The reduction gears are fully enclosed and lubri-
cated within the primary chaincase and require no
attention.
The drive "“sprag” (or clutch) runs on the engine:
mainshaft engaging the drive between a sleeve on the
final reduction gear and the inside diameter of the
engine sprocket. The final reduction gear contains a
needle roller bearing which runs on a hardened sleeve,
close fitting the engine mainshaft.
4
ee MAINSHAFT GEAR.
Cr
— Engine/Primary Transmission
=
STARTER MOTOR
FREEWHEEL/SPRAG
DRIVING ENGINE SPROCKET
SEE DETAIL “B”.
NEEDLE ROLLER
BEARING FOR
у,
HARDENED SLEEVE 1
FOR NEEDLE BEARING + ч
OVERLOAD BACKFIRE
“een DEVICE SEE DETAIL “A”
DETAIL A“ EXPLODED ARRANGEMENT
OVERLOAD BACKFIRE
DEVICE:
Showing
Assembly
— Order
DRIVING BALLS
>- FIT DETENTS IN GEAR
AND FLANGE
7... DIAPHRAGM
SPRINGS
DETAIL “8” EXPLODED ARRANGEMENT
MAINSHAFT DRIVE-SPRAG
FREEWHEEL UNIT
Showing Assembly Order
SEE FIG. C.00 FOR
ASSEMBLING DETAILS
AND CORRECT ROTATION
OF SPRAG.
Fig. C52 Electric starter mechanism: General arrangement
Engine/Primary Transmission
It is important to check when assembling the drive
sprag-cage inside the sprocket recess that this is the
right way round. Obverse assembly will not drive!
See illustration C.52 for arrangement of mechanism
and diagram C.52(a) for layout of the drive.
See Section J25 for Electric Starter Motor.
SECTION C38
REMOVING AND REFITTING ENGINE
COMPLETE -
For ease of handling the engine unit may be removed
from the mounting plates as a unit so that it can be
dealt with on the bench. Proceed as follows:
1 Remove the left footrest.
2 Drain and remove the outer primary chaincase,
cross-shaft, alternator rotor nut and alternator
stator. The stator can be left attached to the inner
chaincase by the lead but disconnect the two
connectors beneath the airbox and lever off the
rotor.
3 Remove alternator mounting plate, outer thrust
washer (behind rotor) large starter gear. With-
Ll
= pps ee
e877.
DRIVE-SPRAG с:
(FREE-WHEEL) =m NEEDLE
| ROLLER ON
„: | HARDENED
¢ я SLEEVE
RM.23 HEAVY-DUTY
ALTERNATOR ROTOR
Fig. C52(a)
10
BEARING RUNS
draw sprag cage, needie roller bearing sleeve and
thrust washer from sprocket recess.
Extract the starter intermediate shaft from spline
in back gear and remove previous chain tensioner
(wire-in skates to avoid mixing fits).
Slacken off clutch adjustment, compress the clutch
diaphragm spring (this requires too! 060999) and
remove circlip.
Fit clutch hub too! 061015 and remove clutch
centre nut and fit engine sprocket extractor tool
064297. Remove engine sprocket and lift entire
engine sprocket — primary chain — clutch assembly
away.
Remove clutch abutment circlip and internal
fixing nut allowing inner chaincase to lift off its
four studs.
Remove rubber breather hose at rear of timing
chest.
Detach engine ground wire attached to lower left
crankcase stud.
Remove fuel tank, ignition coils, carburettor top
caps and withdraw slide assemblies. Remove
exhaust pipes and upper Isolastic head steady and
suspensory spring device.
PRESTOLITE STARTER MOTOR
{CLOCKWISE ROTATION ON
DRIVING END)
STARTER OUTRIGGER
BUSH OMITTED AFTER
ENGINE No. 325689
OVERLOAD “BACKFIRE” DEVICE
TIGHTENED TO GIVE A SLIP
TORQUE OF 50 tb/tt - 6.91 Kg/m.
REDUCTION RATIO :-
DIRECTLY IN 70 67
STATOR OUTRIGGER — K — = 14,2:1
PLATE 10 33
Diagram of starter gear reduction (and drive track)
1
11 Drain oil from oil tank and remove oil feed lines
from boss beneath timing cover. Remove rocker oil
feed pipe, and oil-pipe from balance pipe tee-
piece.
12 Disconnect the contact breaker lead wires,
tachometer drive cable, and electric starter
terminal, and remove starter.
13 Slip a sturdy support (wood block or metal rod)
between engine and lower frame tubes.
14 Remove bolts holding rear of engine to engine
cradle so engine hinges on front Isolastic mount.
15 Loosen small bolts holding front engine mount
STEADY ENGINE and remove large lsolastic
mount bolt, then the small bolts and lift out front
Isolastic unit.
16 Engine is now free and can be lifted clear of frame
to right side on to work bench.
Refitting is a direct reversal of the foregoing.
SECTION C39
IGNITION TIMING
Ignition timing can be checked and if necessary reset
either with the engine stationary or, using a strobo-
scope, with the engine running. The stationary method
is quite satisfactory where a stroboscope is not avail-
able. However, for greater accuracy, the stroboscope
method is preferable, since it also checks auto
advance function. A timing indicator plate is
attached to the outer primary chaincase to align with
the corresponding mark on the rotor, the marks being
visible after removal of the chaincase inspection cap
(see Fig. C53). The latest Lucas rotor has two timing
markings opposite each other. Note that the presence
of the surplus marking will not affect timing, either
static or with a stroboscope.
To explain — the engine must be running for a strobo-
scope to be used. Setting the timing by the wrone
marking would mean the spark was timed at bottom
dead centre and the engine would not run. If the enging
is timed on the correct stroke, the stroboscope will not
pick up the wrong marking. Similarly with static timing,
only the correct marking will align with the calibrated
scale in the primary case with the piston near top dead
centre on the firing stroke for the cylinder being timed.
Engine/Primary Transmission C
TIMING MARK
ON ROTOR
Fig. C 53 Timing plate visible after removal of inspection cap
from chaincase
Ignition Timing Basic Procedure Prior to
Checking
Straightforward assembly of the auto-advance mechan -
ism and contact breaker assembly is covered in Section
C31 as part of the Timing Cover reassembly procedure.
It is however, necessary to locate the auto-advance
cam approximately prior to timing. It is assumed that
‘the auto-advance mechanism is loose assembled to
the taper in the camshaft and that the contact breaker
backplate screws are central in the adjustment slots.
Remove the inlet rocker cover and the right hand
exhaust rocker cover and both sparking plugs then
turn the engine forwards on the kickstart until T.D.C.
is located on the right cylinder with both valves
closed at the firing position. Identify by wire colouring
the contact breaker points for the right cylinder then
turn the auto-advance cam until it just starts to open
this set of points. Secure the cam with washer and
centre bolt. The engine is now ready for accurate
timing.
Engine/Primary Transmission C
Ignition Timing Procedure — Engine Static
1 Remove both spark plugs.
2 Remove the inspection cap on the chaincase.
3 Remove the contact breaker cover.
4 Clean and adjust the contact breaker points as
described in Section C40.
Note that if, at any later time, contact breaker
adjustment is disturbed or allowed to vary,
ignition timing will be altered. This necessitates
retiming of the engine.
5 Remove the auto advance cam centre bolt.
6 Replace the washer from this bolt with the special
washer 06-0949 having a hole large enough to
clear the central portion of the unit and thus abut
to the cam.
7 Replace the auto advance cam bolt with special
washer, rotate the auto advance to the full
advance position (it will rotate only one way),
hold and tighten the bolt. The washer bearing
against the cam will hold this in the full advance
position. *
8 Establish that the cylinder on which the timing is
being checked has both valves closed at Top Dead
Centre (T.D.C.) and rotate the engine forwards by
engaging top gear and turning the rear wheel,
until this is the case.
The contact breaker points leads are black and yellow
or black and white and this feature allows the operator
to check which set of points are feeding which coil and
cylinder. The factory standard arrangement is for the
left coil and cylinder to be fed by the yellow/black rear
set of points.
9 Rotate the engine backwards gently until the
machined mark on the rotor registers with 28° on
the indicator plate. At this precise moment the
contact breaker points should start to open in
which case timing is correct.
The exact point of separation can be determined by
inserting a strip of very thin paper between the points.
The points will grip the paper when closed. By moving
the engine slowly, a light pull on the paper will dislodge
this at the exact point of separation. Take care not to
leave a shred of paper between the points when using this
method. A preferable method is to use a low wattage
bulb and holder with a short length of wire attached to
the bulb body with a second length of wire attached to
the bulb connection. Crocodile clips should be
attached to the loose end of both wires. Connect one
wire to the contact breaker spring of the set of points
being checked and the second wire to a suitable earth
point on the engine. Switch on the ignition and as the
engine is turned, the bulb will light at the exact point of
separation.
10 If the timing is incorrect, i.e. the points do not open
at 28° before T.D.C., release the two screws in
elongated holes which secure the main backplate
and rotate it in the housing. To advance the timing,
move the baseplate clockwise and to retard, move
the baseplate anti-clockwise. When the timing is
correct, secure the backplate screws.
11 Using the same technique, check that the contact
breaker points open at 28” B.T.D.C. on the firing
stroke for the second cylinder. If incorrect, make
adjustment by movement of the secondary back-
plate. To do so, slacken screws (A) in Fig. C54 and
use the eccentric headed adjusting screws (B) to
move the mounting plate. When timing is correct,
re-secure the screws (A).
Ignition Timing Procedure — Engine Running
(Stroboscope Method)
This method is greatly preferred for extreme accuracy
in setting. Prior to checking timing, clean and set both
sets of contact breaker points to the figure given in
“General Data.” “
Note that late models have two marks on the rotor but
that if the ignition timing is sufficiently correct for the
engine to run at all, the stroboscope will only detect the
correct marking. If the engine has been rebuilt and
ignition timing is being set from scratch, firstly follow
the basic procedure in the preceding text. Commence
stroboscopic timing as follows:
\
(
Remove the inspection cap on the chaincase to”
reveal the degree indicator plate and timing mark
on the rotor. |
Connect the stroboscope to the H.T. lead on the
right cylinder and use a battery separate to that on
the motorcycle to power the lamp, thus eliminating
possible incorrect readings. For the full method of
connection’ follow the stroboscope lamp manu-
facturer's instructions. -
Identify by lead colours the set of contact breaker
points on which timing is being set by the colour
of the wiring at the points and the ignition coil.
Start the engine and run at a steady 3000 r.p.m.
indicated on the tachometer.
Shine the stroboscope lamp on the indicator plate.
If timing is correct, the rotor marking will register
with the 28° marking on the indicator plate. If the
marks do not align, the timing must be adjusted.
To adjust the timing at the first set of points,
release the two screws in elongated holes which
secure the backplate and rotate it in the housing.
To advance the timing, move the baseplate clock-
wise and to retard, move the baseplate anti-
clockwise. Move the backplate on its slots until
the rotor mark and 28° marks align when checked
with the stroboscope then secure the backplate
screws.
Reconnect the stroboscope for the left cylinder
and again check for rotor mark alignment at 28”.
f
If timing is incorrect for the left cylinder, correct by
slackening off the clamping screw for the
secondary backplate for this set of points then use
the eccentric headed adjusting screw to move the
secondary backplate (see Fíg. C54-secondary
backplate screws are marked “A” and eccentric
screws are marked ‘’B’’). Recheck timing with the
stroboscope and when correct, secure the screws
“A”.
Engine/Primary Transmission C
SECTION C40
AUTO ADVANCE UNIT
The auto advance unit fitted behind the contact breaker
plate in the timing cover automatically and progressively
advances the ignition timing as the engine speed
increases, and returns it to the fully retarded or static
position when the engine stops.
To expose the mechanism, it is necessary to remove the
contact breaker plate complete, but before doing so
mark the exact position of the plate so that when it is
refitted the timing is not disturbed.
Remove the contact breaker plate fixing screws and
take off the plate complete with the contact sets.
Ensure that the springs of the auto advance unit are
intact with the taper loops attached to the pins. Check
“the automatic action by turning the cam by hand to the
fully advanced position in which the bob weights will
be fully extended. When the cam is released, the
springs should return the bob weights to the static
position.
Lubricate the mechanism sparingly. Do not over lubri-
cate as an excess of oil may reach the contact breaker
points. If the contact breaker plate has been removed
from its original position without being marked, the
ignition timing should be checked and reset as in
Section C39 when the plate has been refitted.
Fig. C54 Lucas contact breaker
/
Engine/Primary Transmission C
SECTION C41
CONTACT BREAKER ASSEMBLY
Mark III models have the Lucas 10 CA contact breaker
assembly, providing a separate and independently
adjustable contact set for each cylinder, see Fig. C54.
Each contact set is mounted on its own crescent-shaped
assembly plate that is fixed to the circular base plate by
two screws (A). When these screws are loosened, the
.assembly plate can be moved in relation to the ignition
cam (and the base plate) by the eccentric screw (B)..
This permits a very accurate setting of ignition timing
for each cylinder, independently.
Screws C and D are contact plate fixing screws. They
fit into slots in the plate allowing the plate to move and
adjust the contact points.
Y
The circular base plate is secured by two pillar screws
in elongated holes allowing the base plate to move. To
move the baseplate clockwise. To retard, move the
baseplate anticlockwise.
Adjusting Contact Breaker Points Gap
rotated easily by means of the kickstart pedal. A small
mark located near the lubrication slot on the cam marks
the highest lift position on the ignition cam. Rotate the
engine until this mark aligns exactly with the nylon heel
of the contact breaker; at this position the points will be
fully open. Check the gap with a 0-015 in. (0-38 mm)
feeler gauge. If adjustment is necessary, slacken the
contact breaker fixing screws C and D. Move the
contact set by turning the eccentric screw B until the
correct gap is obtained. Tighten the securing screws.
Recheck the gap to ensure that the adjustment was not
disturbed by the fixing screws. Adjust the other contact
set in a similar manner.
Maintenance of the Contact Breaker
Every 5,000 miles (8,000 kilometres) the contact
breaker points should be examined to determine their
condition. Remove the nut securing the contact breaker
spring to the anchor post and lift off the spring heel,
together with the terminals, insulating bush and the
insulating washer. Remove the fixed contact plate
locking screw and take off the fixed contact plate.
'Pdints which are slightly burnt or pitted can be smoothed
with a fine carborundum stone and afterwards cleaned
with a brush moistened in petrol or white spirit; if they
are badly affected they should be renewed.
Before reassembly, smear the contact breaker pivot post
and the cam very sparingly with Retinax “A” grease and
add three drops of engine oil to each lubricating felt.
When reassembling ensure that the insulating washer,
contact breaker spring, terminal and insulating bush are
fitted in the order shown in Fig. C54 and that the
terminal tags are inside the curve of the spring. Finally
retime the ignition as described in Section C39.
SECTION C42
CHAINS
1 The Mark lil model has a fully automatic primary
chain tensioner which maintains the chain in
correct adjustment throughout its permissable life.
See description C14 paragraph 7. Fig. C47
2 The primary chain operates in an oil bath formed
by the primary chaincase and requires no lubri-
cation from an outside source providing the
chaincase level is maintained. The rear chain is
lubricated by aerosol. A can of chainspray is
produced in the tool-kit. However, the rear chain
is not fully enclosed and from time to time requires
cleaning before lubricating.
Chain Serviceabllity
Both In the case of single row (rear) chain and triple
row (primary) chain, chain length extention of 2% is
permissible before the chain is considered to have
reached the end of its usefulness. This figure presumes
that extension is checked only when the chain has been
cleaned thoroughly and that any chain showing
evidence of broken rollers has been discarded.
Engine/Primary Transmission C
Rear Chain
Adjuster (C)
Wheel Spindle Rear Chain
Nut (A) Adjuster Locknut (B)
Fig. C55 Rear chain adjustment
Rear Chain Adjustment -
This adjustment is made by movement of the rear wheel.
Fig. C55 shows the adjustment points. Proceed as
follows:
1 Slacken the rear wheel spindle nuts (A).
2 Release the chain adjuster locknuts (В).
Pull downwards on the bottom run of the chain
to bring the spindle hard up against the adjusters
(C).
Turn each adjuster an equal amount until, with
the rider seated, there is a total up and down
movement, measured in the centre of the bottom
chain run of 2 in. to 1 in. (19:05 to 25:4 mm).
Tighten securely the adjuster locknuts (B).
Tighten the wheel spindle nuts and recheck the
adjustment in at least three places. Should there
prove to be a tight spot, readjust to give the correct
up and down movement at this point.
Finally, resettle rear brake pads as in Section H10,
applying full pressure to the brake pedal a number
of times. Whenever adjustments are disturbed,
always check for satisfactory operation of your
brake before riding machine.
Gearbox
Gearbox
Gearbox
SECTION D1
GEARBOX DESCRIPTION: MARK II CHANGES
The transmission (gearbox) is a self contained 4 speed
unit, completely separate from the engine crankcase and
thus simple and inexpensive for servicing. A robust
aluminium alloy casing with separate inner and outer
covers contains a gear cluster of extra tough nickel
chrome steel. The kickstart drives through an internal
ratchet on the layshaft first gear which in turn drives
the mainshaft and clutch. Selection is foot controlled
through a positive stop mechanism to a rotating cam
plate. Hardened steel selector forks operated by the
camplate position the gear pinions. The basic design of
“the Commando gearbox remains substantially un-
changed but the Mark HI foot shift is removed to the
left hand side of the machine to conform with recent
mandatory requirements in major markets. The modifi-
cation has been achieved with a minimum of new
components in the interest of spares interchangeability.
A simple cross-shaft transfers the operation from the
back of the original inner cover, across the machine (at
a slight angle), through an oil-seal in the primary cover
emerging forward of the clutch. The knuckle pin roller
has been modified to a spherical form to cope with the
slight angle of the new shaft and ensure a smooth, easy
operation.
A small gear on the foot pedal spindle engages a
pinion on the cross shaft conveniently moving the
operating pivot rearwards towards the footrest (now
moved back 3” for improved riding position) and
simultaneously reversing the direction of shift which
now conforms with the standard “Down to change
down — and up to change up” viz: 1st “down”, 2nd,
3rd and 4th “up” (from neutral). (see Fig. D1)
Fig. D1 Gearshift positions
Other refinements include plated shafts on kickstart
and footshift to prevent corrosion and both have LIP
oilseals to obviate seepage.
Sleeve gear bearings are circlip located, and a green
light neutral indicator in the instrument panel is actuated
by a switch and button on the camplate.
With the fixed-centre cross-shaft the gearbox is no
longer adjustable and a fully automatic, oleomatic,
primary chain tensioner — self adjusting — is housed
within the chaincase.
SECTION D2
GEARBOX DISMANTLING
It is not necessary to remove the exhaust system whilst
giving attention to the gearbox, providing the gearbox
is not to be removed from the engine plates.
SECTION D3
REMOVING GEARBOX OUTER COVER
Prior to gearbox dismantling it is recommended that the
gearbox should be drained into a suitable sized drain
tray using the drain plug at the bottom rear of the gear-
box casing. Proceed then as follows:
1 Remove the kickstart by releasing the single
securing bolt. The bolt locates into a groove in the
kickstart spindle and thus it is necessary to remove
this bolt completely.
2 |f the battery is stil connected, disconnect by
removing the fuse before proceeding to the next
operation. Disconnect all connectors from diode
and pressure switch.
3 Remove the two nuts and one bolt securing the
right hand footrest and note that the bolt also
secures the red earth lead tag from behind the
footrest mounting plate.
A nut without washer is used on the footrest
securing bolt. It is vitally important during
re-assembly not to overlook the refitting of this
earth lead or otherwise a short circuit may result
in the fuse being blown, or damage to the Zener
diode.
Gearbox
4 Lift the footrest and brake pedal away and tie up
the assembly clear of the outer cover, allowing
good access. This will avoid disturbing the
hydraulics. The flexible hose gives reasonable
latitude but avoid twisting the hydraulic hose and
always re-assemble without stress in the rubber.
5 Remove the five cheese headed set screws from
the gearbox outer cover.
6 Remove the two screws securing the outer cover
inspection cap which may then be lifted away
complete with gasket.
7 Disconnect the clutch cable from the fork within
the gearbox outer cover.
8 Place the oil drain tray under the gearbox, and,
using the kick shaft as a handle, pull the outer
cover off. It may be necessary to tap the cover
gently to free it.
9 Withdraw the shift ratchet plate and spindle.
SECTION D4
REMOVING GEARBOX INNER COVER
Prior to removing the gearbox inner cover it is necessary
to mark clearly the position of the clutch operating body
by two punch marks which are shown in Fig. D1(a).
This is due to the fact that the clutch operating body has
no positive rotational location. Proceed as follows:
1 Remove the small lever, screw and nut securing
the clutch operating arm and collect the arm,
roller and bush.
2 Remove the clutch operating body locking ring as
in Fig. D1(a) and lift away the clutch operating
body and the ball.
wi
Fig. D1(a) Removal of clutch body lockring. Note alignment
marks on lock ring and cover
3 Prevent the gearbox from turning by engaging top
gear as follows:
Top gear can be engaged by levering the end of
the quadrant carefully to the top of the window in
the gearbox inner cover whilst rocking the rear
wheel. At this stage the mainshaft nut can be
removed. (Enlist the assistance of someone to
hold the rear wheel as the brake lever is dis-
mantled.)
4 In order to remove the gearbox inner cover it will
be found simpler to revert to the neutral position,
again by moving the end of the quadrant down the
window.
5 Remove the seven securing nuts to the gearbox
inner cover. These nuts are all of equal size, five
within the case and two outside.
6 Remove the gearbox inner cover, if necessary
tapping the end of the mainshaft to ease separa-
tion.
The inner cover should then be lifted away, com-
plete with kickstart spindle, with the pawl
assembled and also the return spring.
SECTION D5
DISMANTLING GEAR CLUSTER AND CAM
PLATE
To dismantle the gearbox further it is necessary to
remove the clutch from the gearbox mainshaft and if the
sleeve gear is to be removed from the gearbox, the
countershaft sprocket must also be removed. Clutch
removal is covered in items 1 to 6 of Section C13 and
C14 and countershaft sprocket removal in Section D8.
1 Remove any clutch locating shims, the clutch
locating spacer, and circlip from the mainshaft end.
Remove the low gear pinions from the shafts.
Unscrew the selector fork spindle and remove.
pa
Remove selector forks and withdraw mainshaft
with gears.
5 Withdraw the layshaft with gears. If the shaft is a
tight fit in the bearing heat the case and withdraw
the shaft complete with bearing. The bearing can
then be removed to complete disassembly.
Remove countershaft sprocket (Section D8).
Remove sleeve gear by tapping gently through the
bearing into the gearbox.
Gearbox
8 Remove the acorn shaped detent plunger spring
bolt. This will release the camplate detent plunger
and spring.
9 Remove the bolt and circlip securing the
camplate and quadrant to the gearbox shell.
10 Remove camplate and quadrant and collect
“O-rings.
11 Withdraw the sprocket spacer from inside the
countershaft oil seal.
12 The bearings can be withdrawn for inspection or
replacement by gently heating the case and
tapping the open end on a soft wooden surface.
13 Prise out the countershaft oil seal.
SECTION D6
INSPECTION OF GEARBOX PARTS
After cleaning all components very thoroughly such as
in gasoline (petrol) or kerosene (paraffin) check all
items thoroughly as below :
1 Inspect the two mainshaft and one layshaft ball
journal bearings for roughness indicating ball or
ball track damage on either the inner or outer
races. Feel for side play between the inner and
outer races. If the bearings are in good condition,
such play should be negligible.
2 Inspect both the layshaft and mainshaft for wear
on the splines, damage to the threads, out of truth
and severe wear and grooving on the bearing
diameters.
3 Inspect all pinions for chipping or obvious wear
to the teeth. Ensure that the dogs are not badly
rounded and that the inner splines are a satisfactory
fit to the shafts. Bushed pinions should be
offered to the shafts and checked for excessive
wear by attempting to rock them on the shafts.
4 Inspect the gearbox shell and gearbox inner cover ,
bushes for obvious wear. Note that wear on the
bushes in the shell supporting the camplate and
quadrant can result in bad gear indexing and a
tendency to jump out of gear engagement.
5 Inspect the selector forks and mating grooves in
the sliding pinions for seizure or wear.
6 Especially in cases of bad selection, inspect the
camplate tracks for wear or distortion and ensure
that the camplate spindle is a good fit in the bush
in the gearbox shell.
SECTION D7
REMOVAL OF GEARBOX COMPLETE
Though not normally necessary during overhaul, we
recognise that circumstances may arise which make it
desirable to remove the complete gearbox without dis-
turbing the engine although the primary transmission
must be dismantled fully. In these circumstances remove
the rear three crankcase to engine plate bolts, the rear
wheel and support the motorcycle by the lower frame
rails on a strong box and rembve the centre stand.
Remove completely the gearbox top and bottom mount-
ing bolt and stud and turn the gearbox anti-clockwise
in the engine plates viewed from right side. Force the
rear engine mounting rearwards until the cutaway part
at the bottom right hand side is clear of the crankcase.
The gearbox can then be turned further and withdrawn
horizontally from the right hand side. Only in isolated
cases will it be necessary to take out the front mounting
main bolt to provide still further working space.
SECTION D8
COUNTERSHAFT (GEARBOX FINAL DRIVE)
SPROCKET
The countershaft sprocket is mounted on the mainshaft
sleeve (high) gear and secured by a tab washer and
L.H. threaded nut. The Commando overall gearing
should be varied by changing the sprocket size. For the
road going editions of the Commando, the following
sprockets are available:
Gearbox
040480 Sprocket 19 teeth
060931 Sprocket 20 teeth
060721 Sprocket 21 teeth
060759 Sprocket 22 teeth
063420 Sprocket 23 teeth
063421 Sprocket 24 teeth
Changing the countershaft sprocket
1
10
Remove the outer primary chaincase, cross shaft,
chain tensioner, starter gear mechanism, clutch
and primary transmission and inner primary chain-
case as in Section C14 to gain access to the
sprocket.
Remove set screw and lockplate from sprocket.
The sprocket must be prevented from turning
whilst the left hand nut is released. If the gearbox
is in the frame, leave the rear chain connected and
wedge the rear brake fully. If the gearbox is out
of the frame, pass a length of chain round the
sprocket, holding the ends securely in a vice.
Noting that the sprocket nut is /eft hand threaded,
remove the nut and lift the sprocket clear.
Before refitting the sprocket, ensure that the
sprocket spacer is in place on the sleeve gear
bearing sleeve.
Place the sprocket in position and if necessary tap
fully home with a tube drift.
If the original lockplate has been scrapped in
removal, have a new one available.
Fit and tighten the left-hand nut fully, whilst
preventing the sprocket from turning.
Secure the lockplate with the locating screw.
Refit the inner chaincase, cross shaft, primary
transmission, starter gear mechanism, primary
chain tensioner, gearshift pedal (engaging gears)
and outer chaincase as in Section C34 and fit and
connect the rear chain.
SECTION D9
REFITTING GEAR CLUSTER AND
SELECTORS
After inspection of components as in Section D6 com-
mence reassembly as follows:
1
Fig. D2
Heat the gearbox shell and press the sleeve gear
and layshaft bearings fully into position.
Fit the sleeve gear bearing seal squarely into the
housing, lipped side first.
Fit detent plunger, spring, and acorn nut loosely.
Fit the quadrant with "O”-ring and secure with
circlip and washer.
qu
@
Location of camplate to index plunger. Knuckle end
of quadrant is aligned to top front cover stud
5 Lift the knuckle end of the quadrant until the top
inside radius is directly in line with the top front
cover stud (see Fig. D2), fit the camplate and
sealing ring, engaging the teeth of the quadrant
and camplate so that the notched edge of the
camplate is towards the gearbox sprocket and the
blank smooth edge towards the gearbox inner
cover, the last notch at the bottom engaging with
the camplate index plunger (see Fig. D2).
Secure the camplate with “O-ring, washer and *
bolt. N.B. A button on the camplate operates the
neutral indicator switch, now housed in the gear-
box shell, and connected to the green light on the
instrument panel.
Gearbox
Fig. D3
Fig. D4 Gearbox Arrangement
TUN : - .
"2 =.
Mainshalt and layshaft fitted to gearbox shell
Tighten detent plunger acorn nut.
Fit the countershaft (sleeve gear) through bearing
and seal. Fit sprocket spacer in place inside seal.
Fit countershaft sprocket (Section D8).
Fit mainshaft through sleeve gear.
11
12
13
14
15
16
17
18
19
20
+
Fit the 3rd gear free pinion and bush to the layshaft
(dog side first to face out of assembled gearbox).
Fit the fixed high gear pinion to the layshaft, flat
side first (toward 3rd gear pinion). The shoulder is
to fit against the bearing.
Push the layshaft into the bearing in the gearbox
shell.
Assemble the mainshaft 3rd gear with selector
fork to the mainshaft (selector fork groove side
outwards) and engage the pin with the inboard
cam track (see Fig. D4).
Assemble the main shaft 2nd gear with bush to
the mainshaft, dogs inwards.
Assemble the layshaft 2nd gear with selector fork
(selector fork groove side inwards) and engage
the pin with the outboard cam track.
Fit the selector fork spindle through the selector
~ forks and screw home into the gearbox shell.
Fit the layshaft 1st gear.
Fit the mainshaft 1st gear with shoulder outwards.
Since the quadrant roller cannot be fitted after the
inner cover is fitted, it is imperative that the roller
is fitted into the quadrant knuckle at this time.
Gearbox
SECTION D10
REFITTING GEARBOX INNER COVER
Ensure that the gearbox inner cover is clean on both
inner and outer joint faces prior to assembly. Proceed as
follows:
1 Fit the inner cover gasket.
2 If the kickstart spindle has been removed from the
gearbox inner cover, it must be refitted at this stage.
Assemble the kickstarter spindle to the inner
cover, ensuring that the pawl is behind the stop on
the inner cover as shown in Fig. D5.
3 Assemble the kickstart return spring, aligning the
outboard end of the spring with the mating hole
in the spindle and sliding the spring down until the
spring engages in the hole. Wind the spring as
illustrated in Fig. D6 to tension and engage on the
spring anchor pin.
Fig. D5
Showing kickstart pawl stop on inner cover
4 Fit the inner cover gasket and hold in place with
grease.
Ensure that the two shafts are fully home prior to
attempting to assemble the inner cover to the
gearbox shell.
" EA dog =
ds
A
Assemble the inner cover, ensuring that it enters
over the location dowels, and fit snugly home dur-
ing assembly, at the same time guiding the cover
over the unsupported outboard end of the selector
fork spindle.
Fit the seven nuts securing the inner cover, noting
that two of these fit outside the casings. The seven
nuts should be tightened to a torque setting of 10
to 15 Ibs./ft. (1:383 to 2:074 Kg/m).
Engage top gear, apply the footbrake, and tighten
the gearbox mainshaft nut to a torque reading of
70 Ibs./ft. (9-678 Kg/m).
Assemble the clutch operating lever body com-
plete with lock ring and ball to the gearbox inner
cover.
Tighten the operating lever body ring until the
body is fully engaged and finally tighten the lock
ring to bring the body slot directly into line with
the marks previously applied to the boss in the
cover. Fig. D6 illustrates the alignment procedure
during tightening of the lock ring. If a new cover
is being fitted and no alignment marks are present,
hold the body in the position where the clutch
cable can exert a straight pull, as the lockring is
tightened.
Fig. D6 Kickstart spring located. Note alignment of clutch body
to permit straight pull on clutch cable and operating lever
= PA
Gearbox
11 Assemble the withdrawal lever, roller, bush and
pivot screw and secure the lock nut. Assembly
should be in accordance with Fig. D7.
12 Assemble the ratchet plate and spindle, locating
the peg into the knuckle pin roller. Ensure that the
‘0’ ring is fitted to the ratchet plate spindle.
Fig. D7 Order of assembly of clutch withdrawal lever
SECTION D11
DISMANTLING AND RE-ASSEMBLING
GEARBOX OUTER COVER
To dismantle the outer cover, remove the pawl carrier
assembly and disengage the spring peg from the legs
of the pedal return spring. The pedal stop plate set
screws can now be removed and the stop plate lifted
away, complete with spring.
During re-assembly ensure that the spring retaining
washer is fitted over the main spindle of the pawl
carrier and that the spring has been assembled over the
ratchet plate as illustrated in Fig. D8. Tighten the stop
plate set screws and assemble the splined end of the
pawl carrier past the ‘O° ring in the cover. Locate the
spring peg between the legs of the spring and push the
pawl carrier fully home, engaging between the legs of
the spring. Check the carrier action and that the spring is
correctly located. The set screws should be tightened
only when the action of the pawl carrier has been
checked for full freedom of movement. Now fit the
paw! spring with its double cranked leg downwards,
ensuring a minimum but perceptible clearance, between
the two legs of the spring and the pawl.
SECTION D12
REFITTING THE GEARBOX OUTER COVER
Having dealt with the outer cover as described in Sec-
tion D11, ensure that the joint facing is perfectly clean
and proceed with assembly as detailed below :
1 Fit the inner cover to outer cover gasket, retaining
in place during assembly with a smear of grease.
| “e
LM
Fig. D8 Pawl carrier, spring and ratchet plate assembled
Ensure that the gasket engages satisfactorily over
the cover dowels.
To ensure cover alignment during assembly, retain
the ratchet spring in the central position with the
index finger of the right hand and guide the case
over the kickstart shaft with the thumb of the left
hand engaged through the filler cap hole.
Drive the outer cover fully home and assemble the
five screws of equal length to retain the outer
cover in position. If the cover is very difficult to
push into position, check whether the pawl has
rotated due to the pawl scissor spring not having
been held securely in position, during final as-
sembly. The cover should be removed, the ratchet
pawl reset and re-assembly undertaken.
Fit the kickstart crank, then, operating the gear-
shift pedal on the left hand side of the machine,
check the action of the gearbox, rotating the rear
wheel as the gear pedal is moved to the various
gear positions. Ensure the rubber sleeve is cover-
ing the cross-shaft connecting-piece. If all is well,
replenish the gearbox with oil.
Connect the clutch cable through the inspection
hole in the gearbox outer cover, engaging and
locating the nipple in the operating lever.
Finally assemble the gasket, inspection cover and
screws to the gearbox outer cover, and check the
security of the drain and level plugs.
Carburetor
Carburetor
Carburetor
SECTION El
DESCRIPTION
The Amal concentric float carburetor proportions and
atomises the correct amount of fuel, mixing it with the
air drawn in through the air intake. The jet sizes, choke
bore, throttle needle, and throttle slide cut away ensure
that the correct fuel/air mixture is maintained at all
throttle openings. Initial opening of the throttle brings
into operation the mixture supply from the pilot jet
system which controls the idling speed. As the throttle
is progressively opened the mixture supply is aug-
mented from the main jet which discharges through the
>
@ CABLE ADJUSTER
DÍ. “CABLE ADJUSTER LOCKNUT
PT )_ SECURING SCREWS
TT MIXING CHAMBER TOP
AIR VALVE GUIDE
ho THROTTLE VALVE SPRING
AIR VALVE SPRING ~
~——— NEEDLE CLIP
q NEEDLE
AIR VALVE — THROTTLE VALVE
| TICKLER
CARSURETTER BODY £ TICKLER ASSEMBLY -$
AIR INTAKE TUBE 0%
ST SE
Г À
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= PILOT AIR ADJUSTING SCREW
SPRAY mee — b>
_— | THROTTLE STOP ADJUSTING SCREW
fr
NEEDLE JET
JET HOLDER —
MAIN JET 7 |
FLOAT о) y
——FLOAT SPINDLE
SECURING SCREWS=—-— ЧЕ | =
FILTER -—---—- 8
SANJO —---—- $
RANJO BOLT-—— ——- NOR
TT FLOAT
> FLOAT CHAMBER WASHER
"FLOAT CHAMBER BODY
FLOAT BOWL DRAIN PLUG
Fig. E1 Amal concentric float carburetor
needle jet into the primary air chamber and goes from
there as a rich fuel/air mixture through the primary air
choke into the main choke. The earlier stages of the
throttle opening are controlled by the throttle cut away
and the taper needle which passes through the needle
jet, the taper allowing more fuel to pass through the
needle jet as the throttle is opened.
Type 932 Amal concentrics of 32 mm bore size are
fitted to the 850 cc Mark Hl Commando. An exploded
layout (illustrating both hands) with part descriptions
is shown in Fig. E1. A common airbox serves both
carburetors, this being covered in detail in Section E9.
The Mark Ill now incorporates a low friction throttle
cable lined with P.T.F.E. and easy entry into twist grip.
SECTION E2
CARBURETOR REMOVAL
For ease of handling it is recommended that the car-
buretors are removed attached to the spacers as a pair
as follows:
1 Disconnect the fuel lines from both fuel taps, also
disconnect oil separator pipe from balance pipe
tee-piece.
2 Remove four socket screws and washers securing
the spacers to the head — a shortened socket key
is needed for ease of access.
3 With the balance pipe and cables still connected,
lift the carburetors and manifolds away from the
cylinder head, disengaging the flexible air hoses at
the same time. To service the carburetors indi-
vidually :
4 Disconnect the balance pipe at one end.
5 Remove the two cross head screws and washers
securing the carburetor top.
6 Lift off the carburetor top. throttle and air slides
with cables attached.
The top and slides can be left hanging from the
cables but the exposed parts should be protected
from damage by wrapping in clean cloth.
7 If required, remove the second carburetor in
similar fashion. removing the fuel line by taking off
the banjo bolts.
Carburetor
SECTION E3
CARBURETOR DISMANTLING
The carburetor as detached from the motorcycle is par-
tially dismantled, in that the mixing chamber top and
both throttle and air slides have been removed. If the top
and slides are to be removed from the cables, proceed
as follows :
1 Lift the throttle return spring, note the groove in
the needle to which the clip is engaged then remove
the clip. Collect the needle.
2 Disengage the throttle cable nipple and collect the
throttle valve.
3 Lift the air valve cable and spring, disengage the
cable nipple and collect the air valve.
4 The top is now free to be lifted clear. Dismantling
of parts from the mixing chamber should proceed
as follows:
5 Remove the two screws securing the float
chamber to the carburetor body and collect the
float chamber complete with float and float needle,
also the joint washers.
The float and float needle are manufactured from
white nylon. Lift the float, float needle and float
spindle clear for later examination and drain the
float chamber.
6 Remove the main jet, needle jet.
SECTION E4
EXAMINATION OF CARBURETOR PARTS
The following parts should be examined and replace-
ments made where necessary :
Float: Check for leakage — fuel can be seen in the float
if this condition exists. Check also that the float
needle fits securely.
Float Needle: Check for wear on the seating taper.
Main, Needie and Pilot Jets: Examine for damage
and blockage — never use wire to clear a blockage but
instead use compressed air.
Throttle Valve: Remove any burrs and burnish care-
fully any scores. Deep scoring renders the valve unfit
for re-use.
Throttle Needle: Ensure the needle is not bent or
worn badly on the taper. Check that the clip grooves
are clear and “sharp.”
Carburetor Body: Blow out all internal galleries with
compressed air. Check that all threads are sound.
Examine for excess wear on the throttle valve bore.
Pilot Air Screw: Check for wear on the taper.
E2 Carburetor intake items
SECTION ES
CARBURETTOR REASSEMBLY
Assuming all parts are clean and in sound condition
commence reassembly as follows:
7 Using new friction ‘O’ rings on both screws if the
originals have deteriorated, refit the pilot air screw
and throttle stop screw.
8 Fit the needle jet to the jet holder and jet holder to
the carburetor body.
9 Fit the main jet.
4
X
“и
Carburetor
10 Position the float, with float needle and spindle, in
the float bowl.
11 If the original is damaged, fit a new float bow!
joint washer ensuring it is the correct way round
with the holes aligned to the jet passages in the
bowl.
12 Fit the complete float bowl and secure with the
two screws and washers.
Where the originals have deteriorated, replace the '0'
ring in the mounting flange of both carburettors and
couple the carburetors to the manifolds, securing with
two nuts and plain washers for each instrument. Con-
nect the balance pipe to both manifolds. If the air and
throttle valves and mixing chamber tops have been
detached from the control cables, they should be
re-connected as follows:
13 Place the air valve guide tube and spring over the
air cable (the brass guide assembles with the
flanged end towards the cap).
14 Compress the spring to expose the maximum of
inner cable then pass the nipple through the air
valve to engage at the bottom.
15 Place the throttle valve spring over the throttle
cable and compress it.
16 Feed the throttle cable nipple through the throttle
valve centre hole then engage the nipple in the
adjacent hole.
17 Fit the needle clip to the correct groove.
18 Compress the throttle spring to clear the throttle
valve then place the needle and clip into the
throttle valve from the top with the needle in the
centre hole of the slide. Release the throttle
spring and ensure that the spring fits over the
needle clip.
19 Locate the air valve into the channel of the throttle
valve. The carburetors with manifolds are ready
to refit to the cylinder head. Proceed as follows :
20 Offer the throttle and air valves, assembled to the
cables and tops to both instruments. Ensure that
the throttle needle passes easily through centre
hole of the body and that the key on the throttle
valve mates with the keyway in the carburetor
body. Ensure that the return spring fits over the
abutment in the top.
21 Secure each carburetor top with two cross headed
screws and washers.
22 Mount the carburetors on the cylinder head using
the heat insulators between the manifolds and
cylinder head. Secure with socket screws and
washers.
23 Reconnect the fuel pipes to both petrol taps.
24 Fit both carburetors to the airbox flexible connec-
tors and take great care that these locate both in the
airbox front plate and over the carburetor intakes.
25 Reassembly is now complete and slack should be
taken up in the control cables and the carburation
adjusted as in Section E7.
SECTION E6
FUEL TAPS
Twin taps are fitted. The one on the left side provides
the reserve supply and is recognised by the lack of a
stand pipe inside the tank. Fibre washers sea! the taps
to the tank and must be checked that they are un-
damaged before being re-used.
Both taps operate forwards for OFF. The left tap
moves UP for reserve. The right tap operates DOWN
for main supply.
Always turn tap off when machine parked or stored.
SECTION E7
CARBURETOR ADJUSTMENT
Adjustment should be carried out in the sequence des-
cribed below with the engine at operating temperature.
The exhaust system to be used must be fitted and
preferably the test should be carried out on a slight up
grade so that the engine is pulling. The air lever must be
fully to the tight wire position before adjustment takes
place.
1. Main Jet —- Throttle threequarters to full open.
If at full throttle, the engine runs “heavily” the main jet
is set too large. If by slightly closing the throttle valve,
the engine power seems to improve, the main jet is too
small. With a main jet of the correct size the engine
should run evenly, and be delivering maximum power at
full throttle.
Carburetor
The appearance of the sparking plug is one of the
best indications of mixture strength. To check, set the
carburetors to shut off completely on closing or false
readings will be obtained, then run the machine at full
throttle over the test course, declutching and stopping
the engine quickly. Then examine the spark plugs. If
the plugs have a cool appearance with the central
insulator free from loose black carbon and a light
chocolate colour on the insulator, the mixture is correct.
A rich mixture will be indicated by a black, wet oily
appearance with deposits on the central insulator. Weak
mixture will be indicated by a dry whitish deposit and
"the points may appear to have been overheated.
2. The Pilot Jet — Throttle up to one-eighth open.
Set the engine to run at a fast idling speed with the
throttle shut by using the throttle adjusting screw. Turn
this screw outwards until the engine runs slower and
begins to falter, then screw the pilot air adjusting screw
in or out to make the engine run more evenly and faster.
If the idling speed is still too fast reduce it by means of
the throttle adjusting screw and again adjust the pilot
air adjusting screw until the idling is satisfactory.
Note: When new or re-assembled carburetors are used,
start with pilot screw 14 turns out from the fully-in
position.
3. Throttle Cutaway — Throttle one-eight to one-
quarter open.
If, as the machine pulls away from the idling position,
there is spitting back from the carburetors, slightly
richen the mixture by screwing in the pilot air adjusting
screw slightly. If this is not effective, return the screw
to its former position and fit a throttle slide with a smaller
cutaway. If, with the throttle in this position, the engine
jerks under load and there is no spitting, either the jet
needle is much too high or a throttle slide with a larger
cutaway is required to cure richness.
4. Throttle Needle — Throttle one-quarter to three-
quarters open,
The needle controls a wide range of throttle opening
and therefore the acceleration. Placing the needle in
the lower position, that is, with the clip in the top
groove gives a weaker mixture. Placing the needle in
the higher position, that is, with the clip in the bottom
groove, richens the mixture. If the mixture is too rich
with the needle in the lower position, the needle jet
should be replaced and if the needle itself has had a great
deal of use, replace it also.
5. Pilot Jet
Check again pilot adjustment as the last operation.
SECTION ES
ADJUSTMENT FOR ALTITUDE
It is necessary to adjust carburation on a motorcycle
operated continuously in altitudes greater than 3,000
feet approximately. Motorcycles as supplied from the
factory are already equipped for correct carburation up
to 3,000 feet.
The main jet requires a reduction in size of 5 per cent
at altitudes between 3,000 and 6,000 feet. Beyond
6,000 feet further reductions of 4 per cent should be
made.
Altitude adjustments should only be made if the
motorcycle is used permanently at high altitudes. It is
not necessary to adjust merely for a journey through
mountainous areas.
SECTION ES
TWIN CARBURETOR ADJUSTMENT
It is necessary periodically to synchronise the car-
buretors so that they open and close simultaneously.
Start with the handlebars in the centre position so that
there is no “pull” on the throttle cable which will inter-
fere with adjustment. Proceed as follows :
1 Take up any slack in the throttle cables using the
adjuster on the top of each mixing chamber, then
tighten the adjuster locknuts.
2 Start the engine — this must be thoroughly
warmed up before adjustment commences.
3 Follow the main adjustment sequence in Section
E7 before setting slow running. Itis all-important
to have both throttle valves opening simulta-
neously. To ensure that this is the case, the twist-
grip should be set to allow the engine to run
fractionally over idling speed. Gently screw in
the throttle stops in that position. Return the twist-
grip to the closed position so that the engine runs
on the throttle stops. Now proceed as follows:
4 Lift off one spark plug lead and commence setting
the carburetor on the other cylinder as a single unit.
Carburetor
5 Adjust the pilot air screw and stop screw on the
cylinder which is firing.
6 Reverse the process by replacing one plug lead and
removing the other.
7 Adjust the pilot air screw and stop screw on the
second cylinder.
8 Replace the plug lead — at this stage tickover may
be too fast. If so, lower both throttle stop screws by
an equal amount until idling is correct. Ensure there
is about +” (3 mm) slack in throttle cable. This
slack must be equalized so that throttles open
together.
SECTION E10
AIR FILTER
The airbox fulfils the dual roles of air cleaner and air
silencer. It incorporates a micro-cellular plastic foam
element which must be oil wetted.
Removing and Refitting the Element:
1 Access to the filter is through the front cover plate
which can be detached by removing three bolts.
2 Take out the three set screws bolts securing the
air filter front plate.
3 The foam element has a wire reinforcement and
can be easily withdrawn through the aperture. Care
should be observed not to tear the foam on the
float-bowl drain plugs.
5 The element should be cleaned as described below
or replaced.
6 Reassembly is a reversal of the dismantling
procedure.
Cleaning the Air Filter Element:
1 In normal conditions (every 3,000 miles — 4,800
Km) the foam should be washed in clean petrol,
expelling all dirt; then be squeezed out to dry
before immersing in fresh engine oil.
Fig. E3 Removing air cleaner element
2 Squeeze out surplus oil and refit into airbox.
3 Cleaning should be undertaken more frequently in
dusty conditions.
OIL SEPARATOR
The new oil separator (illustrated in the Engine
Lubrication System Diagram Fig. C29 is des-
igned to separate oil and air expressed by the
engine breather system. Mixed oil/air passes first to the
oil tank where initial separation takes place. The fine
mist that comes from the oil tank breather tower is then
passed through the separator. The remaining vapour is
drawn to the airbox and any residual oil droplets are
sucked into the inlet manifold via the balance-pipe
tee-piece, to be burnt in the combustion, obviating
breather drip and deposits on road or machine.
The device requires no attention except to ensure
that the connections especially into the airbox, have
not become disengaged.
Continued use of the machine on short trips in cold,
humid weather may result in “sludging”, requiring a
clean-out to prevent blockage of the pipes.
—
Frame and Ancillaries
Frame
and
Ancillaries
Frame and Ancillaries
SECTION F1
REMOVAL OF POWER UNIT
In some types of repair, for example, during an accident
repair, where the frame must be changed, it is desirable
to remove the engine/gearbox/primary drive and engine
plates as a group. To remove this assembly, proceed as
below:
10
Turn the seat-lock forward with the key provided
and lift the seat. Release the check cable one end,
and remove the four posidrive screws attaching
the hinge. Lift off the seat clear of oil and grease:
Turn the ring of the twist fastener to release the
top forward end of the left hand battery cover and
lift the cover forward off the rear mounting peg.
Disconnect the battery by removing the fuse from
the fuseholder adjacent to the battery.
Remove the right side panel which is secured by
two screws at the top and a peg and rubber at the
bottom.
Remove the fuel tank (Section F9).
Remove both exhaust pipes with mufflers by
detaching balance-pipe and unscrewing the
finned lockrings using service tool 063968.
Collect the split-rings and spherical seating
washers from inside the ports, to avoid loss.
Remove the nuts and washers holding the
muffler bracket to the two mounting rubber studs
and lift each system away in turn,
Disconnect the rear chain at the split link and
remove the chain completely.
Remove snap connector from right hand diode
and red earth wire at nut. Detach both pressure-
switch wires. All from inside of light-alloy rear
footrest-support plate.
Slacken the right hand suspension unit and
withdraw as far as the locating circlips.
Unscrew and remove axle from right hand side.
Ease the wheel over to the left and withdraw the
chain tensioner clevis. Move the caliper and
mounting plate upwards and insert the tensioner
11
12
13
14
15
16
(pushing together with finger and thumb)
between the friction pads before they clear the
disc, to prevent them falling out.
The Caliper and mounting plate (still attached to
the hydraulic hose) should now be withdrawn
through the frame, inverted and hung by the
mounting plate boss (outside) from the hook on
the rear frame loop.
Leaning the machine to the left on the centre-
stand foot, extract the wheel off the shock-
absorber paddles and withdraw from the “right-
hand rear”,
It is now possible to remove the right hand (light
alloy) rear support plate complete with the entire
hydraulic brake, pedal, and footrest — threading the
caliper through the frame, forward of the sus-
pension strut. This is not essential but prevents
damage and avoids mishaps to the vital brake
system, during this major rework.
The swinging arm must now be removed. The
Mark lll pivot is lubricated by felt-wicks impreg-
nated with SA140 oil inserted each end of the
cottered spindle. These contact felt discs which
feed the oil out to the bushes. Qil drips are unlikely
during dismantling.
Proceed as follows: The new swinging arm
bearing is sealed by welch-washer type end-caps
which require renewing when removed. To avoid
drilling we recommend piercing the right hand cap
with a sharp punch and prising out the disc. This
obviates swarf from entering the bearings.
Remove the felts from behind the disc. The left
hand cap can be knocked out with a long bolt or
similar, if necessary, when the arm is removed
from the frame.
The Mark IH ”King-Pin” — swinging arm spindle
is now located by two cotter-pins engaging in
flats, ensuring a more positive and rigid mounting.
To gain access to these it is desirable to remove
the rear mudguard lower front fixings, swinging
it downwards and rearwards on its top-rear
bridge, — clear of the working zone.
Frame and Ancillaries
17
18
19
20
21
22
23
24
Fig. F1
Detach oil-filter and oil-pipes (this is on the
return side of the system and will not drain the
tank).
Disconnect terminals and detach electric-horn
(above filter).
Remove hoth cotter-pins - driving up from below.
Do not damage threads on cotters. Collect rubber
plugs — one each boss.
Remove the suspension unit bottom bolts.
Take out the swinging arm pivot spindle. It will be
noted that the pivot spindle is threaded internally
to aid removal. Screw a bolt with locking nut into
thread (the 3” UNF main front mounting bolt will
be ideal) tighten the nut and twist and pull the
spindle out. The left hand welch-washer felt disc
will remain undisturbed. See Fig. F6.
Detach tachometer cable from hub unit on axle.
Lift away the swinging arm complete with chain-
guard and left hand wheel components.
Disconnect the tachometer cable (at the top front
of the crankcase).
Dismantle the engine steady (see C1) by
removing the nuts and washers from the rubber
mountings first, to prevent them turning in the
frame. Release the two studs and lift away with the
side plates. Remove the main engine steady plate
>. y \
“, ¢ 7 oe = e
y); JA Salon
@
f
Removing oil junction block securing bolt
26
27
Fig. F2
by taking out the three socket screws and
washers, releasing the suspensory spring device
as in C “O”, Note that the centre screw secures the
ground (earth) lead tag.
Remove the rocker feed pipe after taking out the
three banjo bolts. Collect the copper washers for
re-use.
Release the coil cluster from the frame as an
assembly: (four bolts are used). Disconnect the
H.T. leads at the sparking plugs then tie the
cluster clear of the engine unit with all other leads
still attached.
Remove oil separator pipe from tee-piece on
balance-pipe. Detach the carburetors from the
cylinder head complete with manifolds and
balance pipe. Either removal or refitting of the
securing screws is facilitated by the use of a
shortened socket screw key. Lay the carburetors
and manifold assembly still attached to the throttle
and air cables over the headlamp clear of the
engine unit.
Lifting out power unit to right side
Frame and Ancillaries F
28 Disconnect the contact breaker leads from the main
harness in the area of theframetoprails. Disconnect
starter wire and remove starter (and sealing ring)
by withdrawing three posidrive screws in primary
cover mounting. This enables engine to be
removed under the new airbox.
29 Disconnect the oil tank end of the engine breather
pipe.
30 Place a receptacle of sufficient size to contain the
contents of the oil tank below the rear of the
crankcases, remove the bolt securing the oil junc-
tion block to the crankcases, pull the block and
pipes away from the crankcases and allow the oil
to drain. Alternatively after parting the junction
block from the crankcases, raise the junction block
and tie with wire to the airbox to prevent oil
draining from the tank, or protect the feed pipe
with cardboard and compress the pipe with grips
to prevent oil draining (see Fig. F1).
31 Slacken clutch cable adjustment and lift the cable
nipple from the handlebar control.
32 Remove the front engine mounting by taking out
the centre bolt. Remove the two mounting-to-
crankcase bolts and lift away the mounting. The
Mark HI rubbers are all bonded to the hollow
spindle and the two end-caps retain the units in
one piece.
33 Remove the centre stand. This is secured by bolts
fitted from inboard. Lift the spring clear as the
stand is removed.
34 Disconnect the two alternator leads at the snap
connectors.
The power unit assembly is now secured to the frame
only by the rear mounting. Before removing the rear
mounting stud, coil the clutch cable by the gearbox.
Unclip the C.B. leads from the frame and coil them by
the timing case. Protect the lower frame rails against
damage using cardboard or thick cloth.
35 Support the weight of the power unit and use a
soft drift to drive out the rear mounting stud.
36 As shown in Fig. F2, lift the power unit bodily
from the frame to the right hand side. Raise the
front of the power unit and lower the rear to clear
the airbox. The clearance is minimal but with the
electric-starter removed the operation is possible.
SECTION F2
ISOLASTIC ENGINE MOUNTINGS
The Norton Isolastic principle built into the Commando
couples together the engine, transmission, swinging
fork and rear wheel. This assembly, parted from the main
frame is seen clearly in Fig. F3.
Isolation of the engine transmission swinging fork
and rear wheel is achieved by the use of resilient mount-
ings shown as A, B and C. Unlike earlier attempts at
rubber mounting, the Commando is unique in that the
swinging fork is mounted on the engine cradle and thus
isolated from the main frame. This prevents twisting
between the engine and rear wheel sprockets under
load which would otherwise cause premature chain
wear or displacement of the chain.
The power unit in its mounting plates oscillates on
the rear mounting (B). This arrangement provides maxi-
mum support, particularly to the swinging arm and rear
wheel, whilst isolating the power unit from the frame.
The front mounting (C) controls the degree of move-
ment of the power unit on the rear mounting and the two
main and two “buffer” rubbers allow more flexibility
than does the rear mounting. All rubbers are now
bonded and positively located to prevent shuffling.
| Frame and Ancillaries F
47-8 men yo 57-16 тт 0/0
25-4 mm DIA X 14 SWG
4-71mm 24892 mm
5715mm op x 16 swa
Fig F4 Frame checking charts
“—
Frame and Ancillaries F
Both the front and rear mountings incorporate
plastic thrust washers to permit side play to be kept
within very restricted limits without transmitting engine
and transmission vibrations to the rider. The degree of
side play is controlled by adjustable, lockable collars —
a new feature on the Mark 111 — enabling the clearance
to be kept within design limits even after considerable
mileages. (See Technical Data for Adjustment dimen-
sions and method) and Frame Section F12 for full
details of Isolastic Adjustable mountings.
The engine head steady (A) completes the triangular
formation of the resilient mountings and controls lateral
movement of the engine unit in the frame. The insulating
rubbers are fitted between the side plates and frame
tube. An additional suspensory spring device is
incorporated on the Mark II} to improve isolation at low
engine r.p.m. See Section C1 for particulars.
SECTION F3
FRAME CHECKING DIMENSIONS
During the course of an accident repair, the frame must
be examined most carefuily for damage to tubes, welds
and fixing lugs. It is then essential to check for distor-
tion and misalignment. Fig. F4 shows the Commando
frame measurements which should be used to establish
whether or not damage has occurred. However, before
stripping out the frame from the motorcycle, one quick
visual check can be made on vertical alignment at the
steering head tube after removal of the front fork
assembly. This is accomplished by a long tube (approxi-
mately 4 ft. (121 cm) ) inserted as a tight push fit through
the steering head races. Viewed from the front, the tube
should be seen to be perfectly aligned to the motorcycle
centre line. Severe damage will immediately be shown
up by this method and will obviate unnecessary dis-
mantling at the estimating stage.
It is recommended that the frame is checked more
accurately when removed from the motorcycle, to the
dimensions given in the checking chart.
SECTION F4
REFITTING POWER UNIT
Prior to refitting the power unit, if any major mechanical
attention has been given, wash the oil tank and oil pipes
out very thoroughly to remove dirt and foreign matter.
As with dismantling, protect the lower frame rails
against damage. Proceed as follows:
1 Pass the power unit into the frame from the right
side, raising the front slightly and lowering the rear
to clear the airbox.
2 With the power unit loosely in position, move the
rear end as far as possible to the right side of the
frame to facilitate assembly of the rear mounting.
3 The new Mark li adjustable, fully bonded engine
mountings, see F12-,16_.are unlikely to need
attention except for final adjustment and can be
re-assembled after inspection of plastic washers.
Where they are to be assembled without further
attention proceed as follows:
4 Grease, using silicone grease such as Releasil No.
7. on all faces of washers, face rings and end caps.
Position the spacer between the left hand alloy
footrest mounting plate and battery tray bracket
and slide in the mounting stud from the left side,
moving the power unit as necessary to align the
stud holes.
5 Tap the main stud right through aligning with the
right frame bracket, insert the footrest plate and
spacer, then fit the washer and nut. Tighten to
30 Ibs./ft. (4-15 Kg/m).
Frame and Ancillaries
BALLAST RESISTOR
SUPPRESSED HIGH
7 TENSION LEADS
Fig. F5 Coil cluster from rear beneath
10
Fit the front engine mounting plates to the crank-
cases, sliding the long end of the mounting over
the lower crankcase bosses. With the stud or bolt
fitted, pivot the mounting up into position to insert
the second stud or bolt. Almost certainly the power
unit will need to be lifted to insert the crankcase
studs (or bolts).
Grease the end caps with a silicone grease and
reassemble the front mounting as in Section C32.
Adjust front and rear mountings as described in
Technical Data. This will give 0-005 in to 0-006 in
clearance as recommended by “Engineering”.
Tighten the centre bolt to a torque of 30 Ibs./ft.
(4-15 Kg/m).
Refit the oil pipe junction block, using a new
gasket if necessary and securing with the single
bolt which must not be overtightened. (8 Ibs/ft.
1:10 Kg/m)
Prior to refitting the carburetors and spacers,
grease the manifold screws lightly and run them
into the cylinder holes to ensure that they can be
tightened by finger pressure only when the car-
burettors and manifolds are assembled. During this
operation and before attempting to fit the engine
to the frame block the inlet ports with clean non-
fluffy cloth to prevent a screw dropping down one
of the ports: Remember to remove the cloth before
fitting the carburetors.
11
12
13
14
15
16
17
18
F
Holding the Tuffnol insulating block in place
fit the air hose to the airbox using a screwdriver
blade to enter the lip, then assemble the right
carburetor and manifold to the head tightening
the socket screws completely.
Fit the air hose to the airbox, then offer the insulat-
ing block, carburetor and manifold to the cylinder
head, tightening the socket screws as far as possible
with the fingers. When locking up the screws an
abbreviated socket key is essential.
Attaching the suspensory spring unit with its
loop positioned as previously (See C1 (a).
Fit the main head steady plate to the cylinder head.
securing with three socket headed screws. Note
that the centre screw secures the ground (earth)
tab on the red leads.
Position the two spacer tubes in the head steady
plate and offer the side plates over the rubber
mounting studs. Pass the two studs through the
side plates and spacer tubes and secure with the
washers and nuts. Lastly, fit and tighten the nuts
at the rubber mountings.
Pass the rocker feed pipe behind the fuel line 'T'
piece and between the manifolds. The double end
of the pipe fits to the right side of the rocker box.
Ensure copper washers are fitted to both sides of
each banjo and secure with the banjo boits.
Refit the coil cluster, (the cluster is illustrated in
Fig. F5) and reconnect the contact breaker leads
colour to colour.
Reconnect the crankcase breather pipe at the oil
tank and the separator pipe to the tee-piece on
balance-pipe. Refit the earth wire to the top left
nut on the crankcase stud.
Reconnect the tachometer cable to the abutment
at the top front of the crankcase, ensuring that the
cable adaptor is fitted square upwards and that it
has engaged with the drive before the cable union
nut is tightened.
M
Frame and Ancillaries
19
20
21
22
Reconnect the clutch cable at the handlebar con-
trol and adjust the cable to give + in. to { in. (4
to 6 mm) free play.
Reassemble the starter motor (making sure the
rubber sealing ring is over the spigot). Tighten the
three posidrive screws, one through the primary
cover joint, and two through the mounting flange.
Re-connect the starter wire to the terminal on the
body and replace the rubber boot.
N.B. The presence of an outrigger journal on the
armature shaft may cause confusion. It has been
found that the starter motor functions more
satisfactorily and freely without the additional
bearing, and the bush has not been fitted in the
mounting flange since Engine No. 325689.
Refit the centre stand with the pivot bolts passing
through the engine plates, spacers and stand,
inboard to outboard. Fit the nuts and tighten fully
on to the spacers. Hook the long end of the centre
stand spring into the L.H. rear engine plate then
use a length of twine over the stand end of the
spring to expand it whilst locating the hook in the
stand cross tube.
Prior to refitting the swinging arm (which in this
exercise still has the sprocket, speedo gearbox,
and chain-guard attached) ensure .that the pivot
area is perfectly clean, that the sintered bushes
are oiled lightly and that the special moulded
sealing washers are interposed under the bush
flanges on the inside joints. Eventually, lubricating
23
24
25
26
felt plugs, previously soaked in SAE140 oil must
be fitted in the 1” dia tapped bores in the King-Pin
and the "penny-washer” felts assembled under
the end-cap welch-washer providing sealed-in
lubrication for the bearing.
With the left-hand welch-washer and felt “penny-
washer” already fitted, and the moulded sealing
rings trapped under the bush-flanges, push the
swinging arm forward to align the bushes with
the bore.
Using a 4” UNF bolt (the main isolastic bolt is
suitable) with a locknut screwed into the right-
hand end of the swing-arm pivot spindle (King-
Pin), insert the left-hand cotter from above — flat
facing flat, — and push the spindle home. Making
sure the oil soaked felt plug is fitted in the 1”
tapped recess, forward. The spindle can be felt
carefully past the cotter which will stop the initial
progress through the bore, and, with care, obviate
the annoyance of knocking out the left-hand
welch-washer, and a time-wasting rework. If
there /s any doubt after an “over-shoot”, always
check and re-affirm a satisfactory end-seal before
reassembling the arm as the exclusion of road grit
and water is essential to ensure the full life of this
heavily loaded bearing.
With the spindle home and the left-hand cotter
located draw in the second cotter. The right-hand
pin has a wider side tolerance to ease assembly —
the left-hand cotter is the lateral locator.
Remove the bolt and nut used during fitting of the
pivot spindle.
~ >
Frame and Ancillaries
27 Fit the right-hand felt-plug impregnated with
*SAE140 oil into the tapped recess in the King-Pin,
install the flat felt washer (also oiled) and knock
in the welch-washer to effect a permanent seal
and exclude all road-grit and tire-splash.
(The bushes are sealed and lubricated for life)
Insert rubber plugs in the top of each cotter boss.
*N.B. The assembly department at the factory use
140EP oil and 2% Molybdenum Disulphide
additive.
Fig. F6 Removing (or aligning) swinging arm spindle
28
29
30
Refit the rear chain to the Sprocket unit, now
installed with the swing arm. The chain must pass
over the bolts within the chainguard and over the
countershaft (gearbox) sprocket. This is facilitated
by engaging top gear, tying the clutch lever back
to the handle-bar then cranking the kickstart to
revolve the sprocket and pull the chain over.
Engage neutral and pull the chain through suffici-
ently to connect the bottom run. Release the
clutch lever.
Refit the right-hand support plate complete with
the hydraulic master cylinder, brake pedal and
footrest (previously dismantled as a complete
sub-assembly) threading the caliper through the
31
32
33
F
frame, inverting and supporting it on the hook
provided. Ensure that spacers are correctly fitted
behind the plate. This requires some dexterity but
is easier with the wheel removed. Re-connect
“lucar”’ to the diode, red wire to the earth-nut. and
the two contacts to the master cylinder-pressure
switch.
Refit electric-horn and reconnect terminals.
Refit oil filter and reconnect return pipes.
Reassemble rear mudguard to forward fixings.
The tail lamp harness has remained undisturbed
along the frame loop.
Fig. F7
Swinging arm pivot](king pin) and cotters.
34 Refit the rear wheel (see Section HO). Take care
to untwist the hydraulic hose and when the caliper
is reassembled to the disc apply the rear brake
forcibly a number of times to settle the friction
pads back in correct relationship to the disc.
THIS IS MOST IMPORTANT AND MUST BE
DONE AFTER ANY WORK INVOLVING THE
BACK WHEEL (INCLUDING REAR CHAIN
ADJUSTMENT).
Frame and Ancillaries F
35 Refit the exhaust system, (see Section F19)
ensuring that the spherical seating rings are in
position in the ports and the split rings behind the
finned lockrings adjacent to the pipe-flanges.
Tighten the finned lockrings with service tool
063968 or a similar suitable ‘C’ spanner.
36 Refit the fuel tank (see Section F9) and reconnect
the fuel pipes.
37 Refit the fuse.
38 Refit the battery cover and right side cover.
39 Check all oil levels and top up or refill as necessary.
40 Replace the seat and check wire, and secure with
the knurled side knob, after engaging lock-claw
with key turning anti-clockwise to lock.
SECTION F5
REMOVING AND REFITTING SUSPENSION
UNITS
In order to replace or dismantle the suspension units it
is necessary to remove them from the motorcycle as
follows:
1 Remove the nut securing the bottom of the sus-
pension unit and pull the unit clear of the swinging
arm.
2 Unlock and lift the seat. Removing altogether by
dismantling the four posidrive screws at the hinge,
if preferred.
3 Slacken off the knurled knob as far as possible to
gain spanner access to the integral hexagon of the
suspension unit top bolt.
4 Holding the bolt by the hexagon to prevent turning,
remove the nut and plain washer from behind.
5 Support the weight of the suspension unit and
remove the bolt.
The suspension unit is now free to lift clear of the top
frame lugs.
Refitting is a reversal of the foregoing but on re-
assembly ensure adequate clearance between the
suspension unit top collar and any carrier equipment
which may be fitted.
SECTION F6
REAR SUSPENSION UNITS (GIRLING)
The rear suspension units are of the spring controlled,
oil damped, telescopic type. Adjustment of static spring
loading is accomplished by rotating the three position
castellated cam ring at the bottom of the spring. To
adjust, support the motorcycle on the centre stand and
use a ‘C’ spanner to turn the cam ring. Turning the cam
ring to the left increases the loading to cope .with
additional loads and vice versa. Both units must be on
the same loading — if in doubt, start both units from the
light load position. The damper units are factory sealed
thus cannot be serviced. The springs can however be
removed. Bonded rubber bushes are used top and
bottom for mounting the suspension units. These can be
pressed out for replacement and new ones pressed in,
smeared with a lubricant such as soap to ease entry.
IMPORTANT NOTE
lt is important always to check the assembly and
function of the rubber mounting bushes on suspension
units.
As designed the inner sleeve is proud of the outer,
and will always oscillate freely within its rubber when
clamped up.
In the unlikely event of misuse or damage resulting
in a shortening of the inner sleeve, (or incorrect
replacement of the sleeve by a shorter version), the
bush could be clamped up solid, preventing torsional
freedom and eventual fatigue failure of the attachment —
weld to the strut.
Frame and Ancillaries
/
NO GAPS
Fig. F9 Fig. F10
Fig. F9 Suspension unit assembled with correct length sleeve
Fig. F10 Suspension unit assembled with sleeve of incorrect
length
Fig. F11 Failed suspension unit with ferrule detached
When locked up, normal articulation of the swinging
arm causes movement of the suspension unit body, not
the affected ferrule, and a fatigue failure occurs. See
Fig. F11.
Check that the top and bottom suspension unit mount-
Check that the top and bottom suspension unit
mounting bolts are tightened to 28 Ibs./ft. Grasp the
suspension unit in the hand and turn axially in one
direction then the other on the mountings as shown in
Figs. F12 and F.13
FAULTY
ORRECT
ame pates,
ED
FERRULE ABLE TO MOVE
Fig. F12
FERRULE LOCKED UP SOLID
Fig. F13
Fig. F12 Grasping suspension unit and turning axially —
showing ferrule freedom of movement
Fig. F13 Grasping suspension unit and turning axially —
shows ferrule unable to move
The ferrules of each suspension unit should move
visibly on the bonded rubber bushes within the side
plates as indicated. If there is freedom of movement,
no further action is necessary since no fault is present.
If there is no movement, the inner sleeve of the
bonded-rubber-to-metal-bush sleeve is of insufficient
length. The comparative measurements of correct and
incorrect sleeves are shown in Figs. F14 and F15.
CORRECT
-
FAULTY
IMPORTANT
DIFFERENCE
"
ED
L4 0:745
0.755" ~ 0.660"
Fig. F14 Fig. F15
Fig. F14 Correct length sleeve showing comparison point
Fig. F15 Incorrect length sleeve flush with suspension unit
ferrule
Where a suspension unit is identified as having a sleeve
of insufficient length, the whole suspension unit must
be replaced, together with the other side suspension
unit which may have suffered undue stresses as a
result. In these circumstances contact your dealer
immediately. In bonafide cases he is authorised to
replace faulty units free of charge.
When fitting new suspension units ensure that the
securing bolts are tightened to 28 Ibs./ft. and that
there is freedom of axial movement on completion.
FOUL CAN
OCCUR IF
THE WELD
I$ GENERDUS
CALIPER
YT Y:
&
) 7
i»
Fig. F16 Fig. F17
Fig. F16 Suspension unit assembled fouling caliper plate.
Fig. F17 Suspension unit assembled with clearance restored.
Frame and Ancillaries F
CAUTION:
Mark lll Commando rear disc brake: critical assembly.
Always ensure adequate clearance between the caliper
mounting plate and suspension strut where the bottom
weld adjoins the plate. This is a variable and can result
in a foul. A packing washer will rectify this and remove
any stress from the bush. The bolt will accommodate
the extra length and overhang.
SECTION F7
CHANGING THE SPRING
In order to change a spring it is recommended that the
suspension unit is gripped in a vice by the bottom
mounting. Turn the castellated cam ring to the light
load position. The help of a second operator is needed
so that as the spring is grasped firmly in both hands and
compressed down, the second operator lifts clear both
split collars. Pressure on the spring is now released and
the spring can be lifted clear. Reassembly is a reversal of
these instructions.
SECTION F8
REBUSHING THE SWINGING FORK
After long usage, the two flanged bushes working on
the spindle may wear. After removal of the swinging
fork (Section F1 (9-22) wash all parts very thoroughly
in gasoline (petrol). Insert the pivot spindle and check
the fit. Excessive working clearance will permit unac-
ceptable side movement at the rear wheel and this must
be rectified by renewing the spindle, bushes, felt
wicks, washers and oil sealing rings. Renewal of these
items should be dealt with as follows:
1 Remove the welch washer from the remaining
boss on the swinging arm. This will press out or
knock out easily from the opposite side.
2 Using a light press and a suitable shouldered press
tool, press out the first bush, releasing the large
bonded sealing washer trapped under the bush
flange.
3 Repeat for the second bush.
Fig. F18 Swinging arm bushes showing order of assembly
New bushes are pre sized and do not require reaming
after fitting. Assemble as follows:
4 Place the bonded sealing washer over the bush as
in Fig. F18 and press the bush in fully. |
Frame and Ancillaries
HI - RIDER
INTESTATE
INTERPOL
H!- RIDER
ROADSTER
INTERPOL
RADIO POMMELS RADIO RECESS
Fig. F19 Mark Ill Fuel tanks and fixings
INTERSTATE
F
Frame and Ancillaries F
5 Repeat for the second sealing washer and bush.
6 Place the felt disc (previously impregnated with
SAE140 oil) in the recess in the left-hand boss and
press home the welch-washer. The right-hand set
will be fitted after assembly into the machine.
The swinging arm is now ready to refit to the motor-
cycle, using a new spindle if the original shows signs of
wear. Remember you will need new welch-washers and
must ensure the “plug-wicks” and felt discs are fully
impregnated with SAE140 oil before assembly. These
must provide lubrication, for life, of the replacement
bushes!
SECTION F9
REMOVING AND REPLACING FUEL TANK
Prior to removal of any fuel tank, remove the seat. This
will permit easier access to the rear tank fixings. Dis-
connect the fuel pipes from both fuel taps at the pipe
union nuts.
The method of fixing is illustrated in Fig. F19. The front
mounting utilises studs, self locking nuts and loose in-
sulating washers, providing a form of insulation from
the frame front tank member. This mounting is common
to all Mark HI types.
The rear fixing employs resilently paddad steel
cross-straps straddling beneath the main frame tube
secured by bonded rubber isolators. Moulded resilient
paddings cap the tank top tube, fore and aft, fitting the
tank channel.
The various tanks fitted to the Mark lll Commando
models are illustrated on Fig. F19 with model designa-
tions
FUELS
The Mark Ill Commando is designed to operate on fuels
of at least 94 octane rating. (U.K. 3 star or U.S.A. pre-
mium. See section K1: and Rider manual; P. 15/17.
SECTION F10
REMOVING AND REFITTING OIL TANK
Prior to dreining the oil tank, take the motorcycle for a
short run to warm the oil which should then flow more
freely. Have available a receptacle of sufficient size to
receive the contents of the oil tank. Remove the seat
after releasing the large knurled side knob.
A common oil tank is used on all 860 Commando
Mark II! models and the following instructions apply
to all editions.
Frame and Ancillaries F
1 Remove the two hexagon headed screws and
washers securing the right hand side panel.
2 Remove the drain plug and allow oil to drain into
the receptacle previously obtained.
3 Pull the crankcase breather pipe and oil tank
breather pipe away from the oil tank.
4 Remove the large hexagon headed oil tank filter at
the rear of the oil tank.
5 Pull off the oil return pipe from the stub at the rear
of the oil tank.
6 Remove the nut and washer securing the oil tank
to the top rear mounting.
7 Siacken only the nut on the top front flexible
mounting (the bracket is slotted and will then
slide clear).
8 Using an extension socket wrench, remove com-
pletely the bolt fitting through the bottom mounting
into the base of the oil tank.
9 Pull the bottom of the oil tank outwards so that the
filler neck clears the frame, slide the tank forwards
and outwards, lifting the bottom clear first.
10 Reassemble as a reversal of the foregoing. Take
care not to omit the spacer from the bottom mount-
ing rubber.
SECTION F11
L.H. BATTERY AND R.H. SIDE COVERS
The left hand battery cover is retained by a Dzus
fastener at the lower front of the cover. To remove, pull
and turn the ring of the fastener. The cover is then pulled
away from the frame at the front and lifted off the rear
peg. On al! but certain Interpol models, the cover can
be lifted clear. On Interpol models with alternating
horns, the horn relays and control boxes are located
within the battery cover and the cover cannot be
removed completely without disconnecting the horn
wiring.
Mark lil models have a right hand side cover secured
at the top by hexagon headed screws and washers, and
supported by an extension with rubber grommet at the
bottom, fitting inboard of the footrest support plate.
SECTION F12
ISOLASTIC ENGINE MOUNTINGS
The Mark II! Commando lsolastic Suspension in-
corporates redesigned, adjustable front and rear
mounting units employing fully bonded rubber bushes,
simplifying assembly procedure and eliminating scuf-
fling in service. Adjustment is straight-forward and
requires no special tools. A spoke or suitable small dia. |
screwdriver is all that is required as a tommy bar to turn
the adjustable end cap, which is located on the right
hand side at the front and the left hand side of the rear
mounting. The opposite side in each case has a fixed
end cap located by a grub-screw lock.
ADJUSTING ENGINE MOUNTINGS
Prior to checking adjustment or dismantling note that
Mark III models must be supported by a stand or strong
box placed below the main frame tubes with the centre
stand folded. This is necessary due to the stand being
mounted direct onto the engine plates on these models.
On such models the mountings would be under tension
with the centre stand in use. Proceed as follows:
SECTION F13
CHECKING AND ADJUSTING FRONT
MOUNTING CLEARANCE
1 Slide the right side gaiter back to give access to
the adjuster and plastic washer.
2 Push or lever the engine to the right until all slack
in the Isolastic mounting has been taken up.
Holding the engine unit in this position, use feeler
gauges to measure the clearance between the
plastic washer and bright plated adjuster collar.
(See Fig. F20).
3 If the clearance exceeds 0-010 in (:25 mm) the
unit should be readjusted.
4 Following the procedure defined in Technical
Data: Slack of the main mounting central bolt, and
slide spring clips clear of holes in adjuster.
Frame and Ancillaries F
5 Insert suitable size tommy bar (spoke or similar)
into a convenient hole in the adjusting collar and
screw up until there is no clearance.
6 Back-off adjuster, moving 1% holes only (to
unscrew), replace spring clip and gaiter.
7 Tighten main bolt to 30 lbs./ft. (4:15 Kg/m)
torque.
8 The clearance will now be approximately 0-006 in
(0-152 mm) as recommended.
|
[
|
Fig. F20 Checking front mounting clearance
SECTION F14
CHECKING AND ADJUSTING REAR
MOUNTING CLEARANCE
1 Slide the left side gaiter back to give access to the
face ring and plastic washer.
SECTION F15.
2 Push the rear wheel to the left firmly and measure
the clearance between the plastic washer and
bright plated adjusting collar.
3 1f the cliearance exceeds 0:010 in (:25 mm) the
unit should be readjusted.
4 Following the procedure defined in Technical
Data: Slack off the main mounting central bolt,
and slide spring clip clear of holes in adjuster.
5 Insert suitable size tommy bar (spoke or similar)
into a convenient hole in the adjusting collar and
screw up until there is no clearance.
6 Back-off adjuster, moving 12 holes only (to
unscrew), replace spring clips and gaiter.
7 Tighten main bolt to 30 Ibs./ft. (4-15 Kg/m)
torque.
8 The clearance will now be approximatley 0-006 in
(0-152 mm) as recommended.
ISOLASTIC ENGINE MOUNTINGS
DISMANTLING AND RENEWAL
Routine checking of clearances will present little
difficulty with the new adjustable mountings ,and with
the fully bonded rubbers and provision to take up any
wear of the plastic washers, it is unlikely that replace-
ments will ever be required.
However, where a mounting has seen long service
it may be desirable to clean out the unit and/or examine
the plastic washers, etc for uneven wear or damage. In
this event the complete unit will have to be removed to
gain access to the components.
It is no longer possible to extract the end caps (as
previous practice) after removal of the centre bolt or
stud.
The front mounting is reasonably accessible but the
rear unit can only be dismantled after a major strip-
down of the primary transmission as described in
Section C13/14.
Frame and Ancillaries F
DISMANTLING FRONT MOUNTING
In order to withdraw the mounting bolt completely it
may be necessary to detach the right hand exhaust
pipe as described in Section 19.
1 Remove the self locking nut and plain washer from
the left hand side of the central mounting bolt.
2 Align the flats on the bolt head to clear the timing
cover as the bolt is withdrawn.
3 Using a soft metal drift, gently drive the bolt out to
the right hand side easing and supporting the
weight of the engine and avoiding damage to the
threads.
4 Remove the two 2” dia. bolts securing the plates
to the crankcase. Lift the mounting away.
5 Remove gaiters both ends.
6 Slide back the spring clip on the adjusting end and
with a spoke or similar tommy bar unscrew and
remove the end cap, holding the assembly in a
— vice if necessary.
7 The plastic washer on the right hand end and the
facing ring can now be removed and cleaned or
replaced as required.
8 The opposite (fixed) end cap on the left hand side
is located to the centre sleeve by a grub screw.
See illustration F21. It is not essential to remove
this end, unless the washer needs replacing, and
the inner sleeve with bonded rubbers can be
withdrawn from the mounting tube sufficiently to
allow examination and cleaning of the washer and
faces.
If the entire unit is to be dismantled it should be
possible to drive the centre sleeve out without
excessive force, the operation being eased by use
of a rubber lubricant applied to the bore. Ad-
ditional side pressure, applied by inserting a
suitable sized bar into the central sleeve will assist
extraction. The front mounting’s are a tighter
designed fit than the rear rubbers.
9
10
The engine mounting, end-caps, facing rings and
plastic washers can now be thoroughly cleaned
and examined. Remove all dirt and corrosion and
where excessive wear, uneven thickness or
damage is evident, replacement is advised. It will
be necessary to unlock the grub screw and
remove the fixed end cap if new items are needed
on the left hand end.
In the unlikely event of deterioration of the rubbers
a replacement bonded unit will be required.
Rubbers are no longer available separately.
REASSEMBLY: FRONT MOUNTING
1
2
Hold the mounting securely in a vice, left hand
side uppermost.
(Using a silicone grease such as Releasil No. 7).
Slightly grease the contact faces of the facing
ring, plastic washer, and fixed (left hand) end-cap.
These items will still be sandwiched between the
fixed end and left hand rubber if found OK, and
dismantled intact, otherwise. new components
will be assembled in the correct order with the
end-cap flush with the sleeve and the grub screw
locked-up securely.
Paint the edges of the large rubbers with rubber
lubricant and squeeze the right hand rubber into
the mounting tube. (It has been found quite
feasible to assemble the new rubber units without
recourse to the original tapered guide body 063971,
but where this is available it should still simplify
entry into the tube). Work the unit through the
mounting tube until the fixed end-cap is fitting
snugly on the plastic washer and face ring.
Replace the left hand gaiter.
Remove and invert the assembly in the vice,
right hand side uppermost.
Using a silicone grease such as Releasil No. 7
lightly grease the contact faces of the facing ring,
plastic washer (both sides) and adjusting (screwed)
end-caps. Insert spoke or similar tommy bar in a
Frame and Ancillaries
10
11
12
13
14
15
16
hole and screw down until the flange pinches the
washer.
Replace the right hand gaiter.
The mounting is now ready for re-installation on
the crankcase.
N.B. Adjustment is finalised with the unit in
position.
Grease outer faces lightly and offer the
mounting to the lower crankcase lug and hold
loosely in position with the bottom stud.
Pivot the mounting up to engage with the crank-
case lug and fit the top stud.
Secure both top and bottom stud nuts to 25 ft./Ibs.
(2:07 Kg/m) torque.
Fit the main mounting bolt from the right side. It
will be necessary to align a flat on the hexagon
to pass the timing case.
This is facilitated by levering the power unit in the
frame, supporting the weight of the engine to
relieve the load on the bolt.
Push the mounting bolt fully home, fit the washer
and nut. Do not tighten at this stage.
Ensure that the gaiters are still located properly
over the mounting, using a small screwdriver to
assist this operation if necessary.
With the main mounting nut still slack, slide the
spring clip away from the holes in the adjustable
end-cap. Insert suitable sized tommy bar (a spoke
or similar) into a convenient hole and screw up
“finger-tight”, taking up all clearance.
Back off the adjuster, moving (unscrewing) 13%
holes only, replacing spring clip. This will give
0-006 in/0-152 mm as recommended.
Tighten the main bolt to 30 Ibs./ft. (4-15Kg/m)
torque.
SECTION F16
ATTENTION TO REAR MOUNTING
After considerable usage it may be expected that the
rear mounting end groups have suffered wear and
deterioration due to corrosion. If the unit is to receive
attention as in Section F15 the power unit must be
removed from the frame as described in Section F1.
However, the need for attention to these fittings is
comparatively rare, and can usually be left until the
power unit has to be dismantled for a major overhaul.
With the power unit removed as described in F1 the
rear mounting is accessible, and although the mounting
tube is smaller in diameter and longer, the basic design
is similar in every aspect to the front layout, except for
opposite — end adjustment and an easier fit of the
rubbers in the bore — needing no special tool for
extraction or assembly.
The procedure for dismantling, cleaning, lubricating
and assembly are the same as for the front.
The adjustment drill is identical — lock up lightly and
“back-off” 11 holes after reassembly in the frame. The
rear mounting stud is also torqued up to 30 Ibs./ft.
(4:15 Kg/m). Refer to F15 for details.
Note: Mark lll model Commandos have been fitted
with bronze-loaded PTFE plastic washers (brown in
colour) in place of the cream coloured polyurethane
washers fitted to earlier models. These washers resist
wear and deterioration; therefore, we recommend they
always be fitted as replacements.
| ENGINE PLATES
ADJUSTABLE END CAP \
Right Handside — Front
Lett Handtide — Rear
\
FIXED END CAP
Left Handside - Front
Right Hand side Rear
Tum Clockwise
(Right- Hand)
To Tighten
FRAME MOUNTING
Fig. F21
FRAME MOUNTING
Mark Ill adjustable isolastic mounting : Engineering diagram
Frame and Ancillaries FF
BONDED TO SPACER
FRONT AND REAR
ADJUSTABLE END
Fig F14 — Isolastic mountings exploded view
Frame and Ancillaries F
SECTION F17
REAR FENDER
Removal and refitting of the rear fender is similar for all
Mark lll models.
1 Unlock and lift the seat.
2 Release the tail lamp with fairing and number plate
support as a group, by removal of six bolts and
plain washers.
3 Disconnect the tail lamp leads (and the direction
indicator leads where fitted) and lift away the tail
lamp and tail lamp fairing group.
4 Remove the bottom front two self-locking nuts and
plain washers securing the rear fender to the
bracket from the frame gusset.
5 Reassembly is a reversal of the foregoing but do
not omit to reconnect the tail lamp leads. Where
direction indicators are fitted, ensure that they
work correctly when reconnected.
SECTION F18
EXHAUST SYSTEM: REMOVAL
1 Slacken and slide both connector sleeves to the
centre of the cross tube and remove.
2 Using service tool 063968 unscrew the finned
exhaust lockrings and allow these to hang on the
exhaust pipes. Collect Split rings and Sealing rings.
Remove the nuts securing the muffler (silencer)
mounting plates to the rubber mountings, so that
at the next stage the mufflers are removed with
plate attached.
Lift each exhaust system clear.
REFITTING :
1
Place spherical seating washers in ports.
Fit L.H. exhaust pipe complete with lockring, and
split rings. Run up lockring but do not tighten at
this stage.
Fit L.H. muffler to exhaust pipe, align the mounting
pommels and assemble loosely to the L.H.
muffler bracket mounting rubbers.
Fit R.H. exhaust pipe complete with lockring and
split ring. Run up lockring but do not tighten.
Fit R.H. muffler to exhaust pipe, align the mounting
pommels and assemble loosely to the R.H.
muffler bracket mounting rubbers.
Slide both connector sleeves to the centre of the
cross tube. Place cross tube in position and slide
both connector sleeves outwards to engage with
the exhaust pipe stubs.
Slacken off all footpeg support and muffler
bracket bolts in the left and right hand aluminium
support plate castings — to allow the brackets to
swivel and adjust to the exhaust pipe/muffler
alignment.
Tighten up the total exhaust system, commencing
at the cylinder head lockrings and cross tube
connector sleeves.
Finally retighten the muffler bracket/support plate
bolts.
Frame and Ancillaries
Fig. F23 Mark Ill Commando exhaust system
— Front Forks/Steering
Front Forks
and
Steering
Front Forks/Steering G
‚ АТ REST (STATIC) COMPRESSING C1
Valve lifted as far as
peg permitting oil to
pass cutaway seat washer
OIL
NOTE: All forks shown BE
less main spring OIL UNDER
LOAD
NA N129
Fig. G2 Fork at rest, compressing, extending and almost fully extended
Front Forks/Steering UG
— FINAL COMPRESSION C2 EXTENDING
| Hp Я Oil forced out
К | ha of damper between
J 117 rod and body
Valve closed onto seat
preventing oil passage
Oil trapped between
bushes forced back
through big hole then
small hole into stanchion
Valve still lifted and oil as big hole becomes
passing to top half of blanked off
damper body
———As stanchion passes Oil sucked into
over damper tube taper, oil | — damper body.
passage progressively
restricted to slow down fork
action and finally provide
hydraulic bump stop
Front Forks/Steering
SECTION G1
FRONT FORK DESCRIPTION
The Commando Fork is a development of the "Road-
holder’ Fork which is world famous as an extremely
strong and precise steering unit under alt conditions.
The Mark {ll caliper is mounted on the left side of the
machine to maintain optimum steering precision and
balance now that the rear disc is mounted on the right
hand side, and the front mudguard stay is deleted to
minimise eddy of road splash into the caliper. The
forks comprise high quality seamless chrome steel
main tubes with light aluminium sliding members for
reduced unsprung weight. Fork movement is controlled
by long single rate springs and two-way oil damping.
The sliding members are supported on oil impregnated
sintered bronze bushes at the top and steel at the bottom
to give maximum support and to minimise wear. The
fork yokes are substantial cast components which
provide great rigidity. The steering head pivot com-
prises two pre-packed and sealed ball journal bearings.
SECTION G2
HOW FORK WORKS
Consider that as the front wheel meets a bump in the
road surface the front forks are compressed against the
main springs. As the wheel passes the bump the forks
are permitted to return to the static position. Should
the motor-cycle become “front end light” such as
negotiating a hump-backed bridge, the fork extends
fully but once again on level road, returns to the static
position. The natural tendency for a spring controlled
suspension system is to over react and oscillate before
returning to static position. Such a system would
result in a pitching motion on rough roads and a
subsequent loss of stability. To counter this condition,
oil damping is provided which in the case of
the Commando fork slows down the spring return
both on compression and extension. Each fork
slider contains 150 cc of oil which is metered by a rod
and valve damper assembly. The damping sequence is
detailed in the following text and the complete fork
assembly is shown in Fig. G4.
FORK AT REST
The oil lies in the bottom of the slider and occupies the
spaces between top and bottom bushes, damper tube
and main tube and occupies the lower end of the damper
tube.
FORK COMPRESSES (C1 and C2)
Consider that the main tube and damper rod remains
stationary thus as the fork compresses, the slider and
damper tube rise. As the slider rises, oil passes into the
lower end of the damper tube. There is no passage of oil
between the damper rod and damper tube cap but oil
passes from the slider through the main tube bleed holes
between the bushes. The vacuum caused between the
fork bushes during compression causes oil to be sucked
from the space between the fork bushes. As the fork
compresses further, the damper tube passes further into
the main tube until the cone shaped bottom area enters
and the oil passage into the main tube is progressively
cut off until only the bleed hole into the damper tube
remains. Oil is then able to pass through the bleed hole
slowly, thus slowing or “damping” the fork action,
finally providing a hydraulic bump stop on full com-
pression.
FORK EXTENDING
The main tube remains stationary whilst the slider and
damper tube descend. Oil remains trapped between the
top and bottom bushes. The damper valve within the
damper tube remains closed thus as the damper tube"
descends, oil passes between the damper rod and
damper tube cap into the space between the damper
tube and main fork tube. As the fork continues to extend,
oil trapped between the fork bushes is forced back into
the slider through the large hole then the small hole to
slow down the fork action and prevent the fork “top-
ping” heavily.
Front Forks/Steering
SECTION G3
REMOVAL OF FRONT FORKS
Removal of the front forks is most easily achieved by
dismantling in parts rather than attempting to remove
the fork assembly complete.
Unfortunately it is no longer possible to remove the
hydraulic system as a complete assembly, and is
necessary to drain and disconnect the pipe line when
dismantling the fork. The Mk Ill has a redesigned
hydraulic pipe run with armour protective cover over
the lower hose and a short hose from the master
cylinder to the top yoke intended to simplify handlebar
change. For convenience and to avoid spillage on
paintwork it is advisable to drain the system using a
small bore tube on the bieeder screw as in Brakes
Section H10 — Bleeding and Flushing (Fig. НЭ).
Discharge the fluid into a suitable receptacle, pumping
the lever slowly until flow ceases. Remember fluid bled
from the system MUST BE DISCARDED.
With the pipe line drained, proceed to disconnect
the olive unions at the bridge lugs (see important note
on olive unions in Section H10).
Release the hydraulic pipe bracket from the left fork
slider at the fender bridge. Remove the two bolts and
spring washers securing the caliper to the slider and
lift the caliper away, complete with pads and still
attached to the brake hose. To simplify reassembly
place a spacer between the brake pads — a suitable
piece of clean wood or preferably a piece of plastic
tubing would be ideal. Remove the four cross-headed
screws securing the master cylinder to the right switch
cluster, hold the master cylinder but allow the switch
cluster to hang on its leads. Pull back the plastic switch
cover from the master cylinder and disconnect both
Lucar terminals. Remove flexible hose and master
cylinder unit, caliper and lower flexible hose to a safe,
clean place; also bundy tube mid-connecting pipe, and
lightly reassemble to protect from ingress of foreign
matter — until refitted. Avoid dust and never use fluffy
rags to cover or wipe components.
Support the motorcycle by using a box or block of
wood beneath the lower frame rails and proceed as
follows:
1 Remove the front wheel (see Section H5).
Remove the instrument panel.
2 Unscrew and lift the fork tube large chrome top
bolts and using two spanners as shown in Fig. G6
release the damper rod from each top bolt.
3 Lift clear the speedometer and tachometer in their
cases and allow them to hang on their cables, and
similarlyremove the instrument panel.
4 Slacken the lower lug socket headed pinch screws
(See Fig. G4).
The fork main tubes are a tapered fit into the upper
yoke and require a shock to free them. The shock may
be delivered by grasping the fork slider with both hands
and snatching downwards several times. If this fails to
break the taper, replace the chrome top bolt at least Six
threads without the instrument case and using a block
of wood to protect the chrome finish (see Fig. G3)
deliver several blows with a hammer. This will release
the main tube from the upper yoke.
5 Remove the first fork leg, replacing the top bolt to
prevent oil loss.
6 Repeat the operation for the second leg.
Note that the steering head bearings are of the sealed
ball journal type which will not be disturbed by removal
of the yokes and stem.
7 Remove the lower yoke. This is accomplished by
releasing the tab washer and removing the large
nut from the bottom of the fork stem. Support the
headlamp and tap the lower yoke downwards
clear of the stem.
Front Forks/Steering ° С
Fig. G3 Shocking main tubes free of upper yoke
8 Collect the two bottom and one top ‘O° ring
released by each headlamp bracket and top cover
and allow the headlamp to hang down on its
harness, with fork covers attached.
9 The upper yoke is now captive only by the tightness
of the stem in the steering head bearings. Use a
hide mallet or soft drift to drive the stem up through
the bearings, allowing the upper yoke to be
removed. Collect the dust cover and washer.
Note: The Mark lil and all previous 850 models use a
special pair of fork yokes identified by "ANG" stamped
on lower surfaces of both yokes. These yokes must be
used for 850's and must not, under any circumstances,
be interchanged with earlier types.
SECTION G4
DISMANTLING FORK LEG
Removal of the fork leg assemblies is described in
Section G3. Pour oil, from the fork leg to be dis-
mantled, into a suitable receptacle and proceed as
follows:
10
11
12
13
14
Secure the bottom of the slider in a plain jawed
vice, with the leg vertical.
Lift the plastic gaiter up the main fork tube.
Remove the threaded collar by hand pressure only,
or, if necessary, by the use of strap wrench 064622
which will not damage the finish.
Grasp the main fork tube in both hands and with a
number of upward jerking movements, free the oil
seal, paper washer and top collar.
Lift the main tube away from the slider.
Remove the damper tube anchor bolt (the various
components are shown in Fig. G4) and collect
the thick washer. -
Lift the main spring and damper tube attached,
clear of the slider.
Collect the bottom fibre washer from the damper
tube for re-use.
Remove the slider from the vice, secure the damper
tube carefully in the vice, taking care not to crush
it.
Unscrew and lift away the alloy damper tube cap.
Withdraw the damper rod.
Grip the rod in a vice and remove the damper rod
locknut, collecting the squared washer and
damper valve.
The damper valve stop pin is free to be removed.
Removal of the square section circlip at the bottom
of each fork tube permits removal of the steel bush.
Front Forks/Steering G
;
О
Fig. G4 Front fork exploded view
SECTION G5
REASSEMBLING FORK LEG
Prior to reassembly, wash all parts very thoroughly in
gasoline (petrol) and allow to dry. Examine for wear on
the fork bushes and main tube. Check that the damper
valve and stop pin are undamaged and that the damper
rod is not bent. When all parts are sound, proceed to
reassemble as follows:
Nn
nl
La \
HOSE BRACKET”
~ BRAKE PIPE
Fig. Gb Hydraulic system fittings to fork leg
1 If the lower bush on the main tube has been
removed, fit a new bush and refit the circlip ensur-
ing that it is bedded well all round.
2 Grip the damper rod in a vice and fit the damper
valve stop pin. The order of assembly is shown in
Fig. G4.
Front Forks/Steering
3 At the peg end of the damper rod assemble the
damper valve, lip end down (when in the vice)
followed by the squared washer and nut which
must be tightened securely.
4 Assemble the damper rod to the damper tube then
fit and secure the damper tube alloy cap.
5 Place the spring over the damper rod and secure
with the thick washer and nut.
6 Place the fibre washer over the end of the damper
tube and offer the damper tube assembled, to the
slider, securing with the thick washer and bolt.
7 Smear the main tube with clean oil then enter it
into the slider.
8 Fit the top bush, paper washer and oil seal : the oil
seal will need to be tapped home using a suitable
tubular drift.
9 Fit the threaded collar and tighten down.
10 Refit the plastic gaiter.
The fork leg is now ready to refit as described in
Section G8.
—u
=
li
|
Ju
Y
Fig. G6 Releasing damper rod from fork top bolts.
G
SECTION G6
RENEWING STEERING HEAD BEARINGS
850 Mark 111 Commando models utilise sealed non
adjustable ball journal bearings with a spacer tube to
prevent the bearings being forced into the frame head
tube. After removal of the forks as in Section G3, the
bearing spacer tube must be pushed to one side so that
a drift can be applied to the inner race of the bottom
bearing and the bearing driven out with care. The bear-
ing spacer will be released at the same time. By using
the drift from the other end of the steering tube the
second bearing can then be driven out,
To replace the bearings, fit the bottom bearing fully
home into the housing absolutely square. Use a should-
ered drift through the bearing to hold it in line with the
housing whilst abutting against the outer race. Place the
spacer tube loosely in position and drive the top bearing
in to abut to the spacer tube.
As the fork yokes are assembled the bearings will be
pulled up to the spacer tube.
SECTION G7
STEERING HEAD ADJUSTMENT
On 850 Commando Mark 111 models — The steering
head bearing arrangement, where the bearings abut to
a centre spacer tube, is non-adjustable. The stem nut
fitted from beneath the lower yoke has a tab washer to .
prevent slackening. See illustration Fig. G7.
Front Forks/Steering G
SECTION G8
REFITTING FRONT FORKS
Reassembly of the front forks is virtually a reversal of the
dismantling procedure though for clarity, the full
procedure is detailed below:
1 Place the top dust cover and washer over the top
steering head bearing. Note that the washer fits
below the cover.
2 Pass the stem of the upper yoke through the
bearings. This will almost certainly require the use
of a block of wood and a hammer to tap the stem
fully home.
3 Lift the headlamp and top covers roughly into
position, place the single 'O' ring in each side of
the upper yoke to locate the tops of the fork covers
Use heavy grease to hold the ‘O’ rings in place.
4 Place the lower yoke, with two ‘O° rings to locate
each fork cover, over the steering stem. Fit the tab
washer and nut to the stem and commence to
tighten. As the lower yoke is raised, locate the top
covers, both top and bottom.
5 Tighten the nut sufficiently to pull the lower yoke
into position, but do not secure fully yet.
6 Offer both fork legs through the lower and upper
yoke and pull the main tube tapers into the upper
yoke using the instrument cases and large chrome
top bolts.
7 With the fork legs secured by the top bolts, snug
the socket headed pinch screws.
8 Now tighten the fork securing points, viz: Chrome
top bolts, main fork stem nut, lower yoke pinch
screws. Note that the stem nut must not be over-
tightened.
9
10
11
12
13
14
Tighten the stem nut to 15 Ib/ft (207 kg/m) and
tap over the stem nut tab washer.
Again lift the large chrome top bolts, firstly to add
oil and secondly to connect the damper rods.
Measure the required quantity of oil for each fork
leg (150 cc of SAE 20). Pouring the oil into the leg
will prove a long operation. To speed up the filling
operation, pour in as much of the measured
quantity as possible, place the hand firmly over
the top of the main tube and extend the fork leg.
Do this several times to speed up oil drainage into
the slider. When the measured quantity has been
added, and with the instrument case held in posi-
tion, connect the damper rod to the chrome bolt as
in Fig. G6. Using a socket wrench on the chrome
bolts, tighten them down on to the fork tubes to
40 lIbs/ft (5.83 kg/m).
Secure the master cylinder to the right switch
cluster with the four long screws.
Bolt the caliper assembly to the left fork slider
using two bolts and washers tightened to a torque
setting of 25 ft/Ibs (3-45 kg/m). Fit the hydraulic
hose bracket over the studs on the left slider
Reassemble all the brake pipe unions and strictly
observe the IMPORTANT procedure directed in
Section H11 (Caliper Assembly) 11, 12, 13, 14,
15, 16 to complete the vitally important assembly
of this brake “pressure-line”. After carefully
examining each union for leaks finally re-check
the fluid level in the reservoir, topping up as
necessary.
Fit the front fender, securing the four plain washers
and nuts at the bridge stay and one bolt and plain
washer at the fork end of the lower stay.
Refit the front wheel as in Section HO6.
Front Forks/Steering G
SECTION G38
REFITTING FRONT FORKS
Reassembly of the front forks is virtually a reversal of the
dismantling procedure though for clarity, the full
procedure is detailed below:
1 Place the top dust cover and washer over the top
steering head bearing. Note that the washer fits
below the cover.
2 Pass the stem of the upper yoke through the
bearings. This will almost certainly require the use
of a block of wood and a hammer to tap the stem
fully home.
3 Lift the headlamp and top covers roughly into
position, place the single 'O' ring in each side of
the upper yoke to locate the tops of the fork covers
Use heavy grease to hold the 'O' rings in place.
4 Place the lower yoke, with two 'O' rings to locate
each fork cover, over the steering stem. Fit the tab
washer and nut to the stem and commence to
tighten. As the lower yoke is raised, locate the top
covers, both top and bottom.
5 Tighten the nut sufficiently to pull the lower yoke
into position, but do not secure fully yet.
6 Offer both fork legs through the lower and upper
yoke and pull the main tube tapers into the upper
yoke using the instrument cases and large chrome
top bolts.
7 With the fork legs secured by the top bolts, snug
the socket headed pinch screws.
8 Now tighten the fork securing points, viz: Chrome
top bolts, main fork stem nut, lower yoke pinch
screws. Note that the stem nut must not be over-
tightened.
9
10
11
12
13
14
Tighten the stem nut to 15 Ib/ft (207 kg/m) and
tap over the stem nut tab washer.
Again lift the large chrome top bolts, firstly to add
oil and secondly to connect the damper rods.
Measure the required quantity of oil for each fork
leg (150 cc of SAE 20). Pouring the oil into the leg
will prove a long operation. To speed up the filling
operation, pour in as much of the measured
quantity as possible, place the hand firmly over
the top of the main tube and extend the fork leg.
Do this several times to speed up oil drainage into
the slider. When the measured quantity has been
added, and with the instrument case held in posi-
tion, connect the damper rod to the chrome bolt as
in Fig. G6. Using a socket wrench on the chrome
bolts, tighten them down on to the fork tubes to
40 Ibs/ft (5.83 kg/m).
Secure the master cylinder to the right switch
cluster with the four long screws.
Bolt the caliper assembly to the left fork slider
using two bolts and washers tightened to a torque
setting of 25 ft/Ibs (3-45 kg/m). Fit the hydraulic
hose bracket over the studs on the left slider
Reassemble all the brake pipe unions and strictly
observe the IMPORTANT procedure directed in
“Section H11 (Caliper Assembly) 11, 12, 13, 14,
15, 16 to complete the vitally important assembly
of this brake “'pressure-line”. After carefully
examining each union for leaks finally re-check
the fluid level in the reservoir, topping up as
necessary.
Fit the front fender, securing the four plain washers
and nuts at the bridge stay and one bolt and plain
washer at the fork end of the lower stay.
Refit the front wheel as in Section H6.
Brakes, Wheels and Tires H
Brakes
and
Tires
Brakes, Wheels and Tires H
SECTION Hi
REMOVAL OF REAR WHEEL
(Without disturbing sprocket or chain)
The Mark II! Commando has a redesigned genuine
quickly detachable rear wheel incorporating a “rubber
in shear/compression” cush-drive and equipped with a
powerful disc-brake, hydraulically operated.
The rear wheel can be removed by detaching it from
the sprocket unit leaving the chain and sprocket
undisturbed, in position on the swinging arm. The brake
caliper can be lifted clear with hydraulic hose attached
avoiding the need to drain the system. A hook is
provided on the top loop to “stow'” it.
Ce n=
Fig. H1 Rear wheel removal
1 Support the machine firmly on the centre stand,
extending the prop stand for additional support.
It is advisable to tie the centre stand to the frame
bottom cross-member beneath the power unit to
prevent the machine from rolling forward off the
stand.
2 Engage 1st or 2nd gear to simplify refitting the
wheel.
10
Slacken the lower right hand suspension strut nut
and withdraw it as far as the locating circlip.
Unscrew and remove the axle from the right hand
side.
Ease the wheel over to the left and withdraw the
right hand chain tensioner clevis.
Carefully lift the caliper and mounting plate
upwards but make sure the friction pads still
engage the disc.
Pinch the chain tensioner clevis together and
wedge it between the friction pads, preventing
them from falling out.
Lift and invert the caliper hanging the mounting
plate on to the special attachment hook provided
on the frame loop (on early despatches use string
or wire).
Lean motor cycle to the left on its centre stand
and extract the wheel, under the tail guard from the
right rear.
Whilst the wheel is removed it is good practice to
check the shock absorber for signs of “granula-
tion” of the inserts.
Fig. H1(a) — Quickly detachable Rear Wheel and Cush-Drive
Brakes, Wheels and Tires H
SECTION H2
REFITTING OF REAR WHEEL
1 Tilt the motorcycle to the left whilst inserting the
wheel with the disc at the right side, between the
swinging arm tubes.
2 Locate the wheel to the shock absorber paddies
(illustration H1 (a)
3 It may help to locate the axle loosely through the
wheel whilst it is held to the left side and the
paddles engaged.
4 With the axle loosely in position, unhook the
mounting plate and move the caliper down (taking
great care to “untwist” the hose), engaging the
hole in the mounting plate to the bottom suspen-
sion bolt.
5 Holding the caliper in position, withdraw the axle
bolt also the tensioner clevis used to wedge the
friction pads.
6 Guide the caliper and pads carefully over the disc
until the plate boss aligns between the wheel and
swinging arm.
7 Open up the chain tensioner clevis, refit to the
right side, lining up the holes — and insert the
axle from the right.
8 Ensure the tensioner fits snugly to the swinging
arm and tighten the wheel axle and suspension
bolt nut.
9 Pump the brake pedal and apply heavy pressure
to restore the friction pads to their correct
relationship to the disc before the brake is used
in service.
10 Remember to fold both stands before riding
machine.
CAUTION:
If for any reason a pad should drop out, ensure that it
is refitted correctly so that the friction material faces the
disc. Position the caliper over the disc with the pads
located correctly at each side of the disc and the pad
“ears” in the caliper slots. Locate the caliper plate siot
on the suspension unit bottom bolt and line the boss
up with the hub. Hold the chain tensioner in position
then insert the wheel axle and thick washer and secure.
Tighten the suspension unit bottom nut. It is essential
to apply the brake several times to restore full pressure
before the brake is returned to service.
SECTION H3
COMPLETE REAR WHEEL REMOVAL
In order to remove the wheel complete, support the
motorcycle on the centre stand and proceed as
follows :
1 Disconnect the rear chain at the split link.
2 Disconnect the speedometer cable from the drive
box on the left hand side.
3 Slacken the lower right hand suspension strut nut
and withdraw it as far as the locating circlip.
4 Unscrew and remove the axle from the right hand
side.
5 Ease the wheel! over to the left and withdraw the
right hand chain tensioner clevis.
6 Carefully lift the caliper and mounting plate
upwards but make sure the friction pads still
engage the disc.
7 Pinch the chain tensioner clevis together and
wedge it between the friction pads, preventing
them from falling out.
8 Lift and invert the caliper hanging the mounting
plate on to the special attachment hook provided
on the frame loop (on early despatches use string
or wire).
9 Remove the left side axle nut and thick washer.
10 Pull wheel over to the right so that the dummy axle
clears the slot in the fork end.
11 The wheel can now be lifted clear.
Brakes, Wheels and Tires H
Rear Chain
Adjuster (C)
Wheel Spindle Rear Chain
Nut (A) Adjuster Locknut (B}
Fig. H2 Rear wheel features
SECTION Ha
REAR HUB DISMANTLING
In order to change the wheel bearings, remove the wheel
complete as described in Section H3 and lift off the
washer, speedometer drive gearbox and internal dis-
tance collar from the sprocket side. With the wheel axle
removed separate the sprocket from the wheel hub —
the “paddles” on the sprocket are a pushfit in the
machined slots in the spider. A double row ball journal
bearing is fitted in the sprocket centre, pinched up on
the dummy axle, with positive circlip location, and
provided with its own oilseal. The bearing arrangement
is clearly illustrated in the “exploded” drawing.
Fig. H3(a).
To dismantle the rear hub proceed as follows:
1 First remove the five attachment nuts and spring
washers and detach the disc, then starting with
the shock absorber side of the wheel unscrew the
LEFT HAND THREAD lockring using peg spanner
too! 063965, and remove. (At this stage it is an
advantage to warm the hub if possible to 100°C
ONLY, if facilities are available. Boiling water
“ladled” over the outside will help.)
2 Extraction of the lockring on the shock absorber
side reveals the sealed ball journal bearing which
provides positive lateral location of the rear wheel.
Removal of the opposite side distance collar from
the oilseal will expose the bearing spacer tube,
and, using the wheel axle bolt as a drift, the spacer
can be driven back into the hub with a hide mallet
(or similar). (35” inward movement approximately
will release the location bearing opposite — the
tube stands 1” proud of the disc side bearing and
provides ample purchase.)
3 With the location bearing removed, the larger disc
side bearing can now be driven out of the hub by
knocking back the spacer tube with the axle
inserted and any suitable distance collar to pack
out the length. Take care to avoid burring the face
of the spacer tube during the operation. The
bearing will drive out the oilseal as it extracts.
4 Removal of the double-row bearing from the
sprocket centre requires extraction of the locating
circlip, using circlip pliers, and driving out the
bearing from the seal side, leaving the oilseal to
be pressed out with a suitably sized drift. Here
again it will assist the operation to warm the
sprocket if possible. Avoid bruising the speedo
drive slots.
SECTION HS5
REAR HUB REASSEMBLY
Prior to reassembly, clean and inspect the bearings and
seals for roughness, wear, damage or corrosion and
make replacements as necessary. Proceed as follows:
1 Pack bearings with the recommended grade of
grease (see Section K1).
2 Reassembly is virtually a reversal of the dis-
mantling procedure. Fit the larger single row
bearing into the disc side of the hub, driving on
the outer spool squarely (preferably under a press)
until it stands under the disc-spigot approximately
18 (7-94 mm). Pack grease over bearing cage
and assemble oilseal flush with face of spigot
(metal flange on outside).
3 Insert bearing spacer tube through bearing until
shoulder touches inner spool.
Brakes, Wheels and Tires H
Fig. H3(a) Rear wheel exploded arrangement, showing order of assembly
Brakes, Wheels and Tires H
Fit the smaller single row bearing into opposite
side (sealed face outwards) after packing with
grease.
Fit the locking ring and tighten. Remember that
the lockring is LEFT HAND threaded. Tighten with
peg spanner tool 063965 until bearing bottoms in
its recess, this will also position the opposite side
bearing if it was too deep in its housing.
The bright distance collar can now be inserted in
the disc side oilseal over the protruding bearing
spacer preventing loss of grease.
The brake disc can now be reassembled on the
five studs and the spring washers installed and
nuts tightened to 20 Ibs/ft (2-76 kg/m).
Check that the shock absorber rubbers are free
from granulation and the paddle slots and paddies
are serviceable.
REASSEMBLY OF SPROCKET BEARING
Pack the bearing with the recommended grade of
grease (see Section K1).
Using a suitable shouldered drift against the edge
of the outer race, drive the double row bearing
squarely into the sprocket centre housing.
Fit the bearing retainer circlip, sharp edge out-
wards, and ensure that it is bedded all the way
round the groove. Failure to observe this pre-
caution can permit free lateral movement of the
sprocket and cause subsequent damage due to
misalignment.
Fit the inner oilseal, squarely and flush with the
face, metal flange outwards from the bearing.
The sprocket is now reassembled ready for accept-
ing the dummy axle, distance collar, speedometer
gearbox and facing washer. A small quantity of
grease can be applied, to be retained by the speedo
gearbox, as it seals off the centre boss when
installed. The unit is now ready for fitting to the
main wheel,
SECTION H6
REMOVING AND REFITTING FRONT WHEEL
Removal
Fig. H4
Disc brake front wheel removal
The brake disc is removed with the wheel whilst the
caliper remains fixed to the left fork leg. and it is not
necessary to disturb the hydraulic system.
1
Support the motorcycle on the centre-stand with
extra support beneath the crankcase to lift the front
wheel clear of the ground.
Remove axle nut ‘A’ from the left (disc) fork leg.
Slacken pinch bolt ‘B’ at the right fork leg.
Taking the weight of the front wheel in one hand
withdraw the axle using a tommy bar. It will be
found that the wheel can be removed most easily
by withdrawing it forwards to disengage the disc
from the pads.
To prevent the brake pads being ejected by
unintentional application of the brake with the
wheel removed, place a clean 3” (6:7 mm) spacer
of wood, metal or plastic between the pads.
Collect the wheel bearing dust covers 'C' and 'D'
to prevent loss. Note that the left one 'D' has an
additional spacing boss. (See Fig. H4).
Brakes, Wheels and Tires H
Refitting
6
Fig. HS
9
Remove the brake pad wedge from the caliper.
Offer the wheel in position from the front, and
with care, guide the disc between the brake pads.
Replace the wide bright plated spacer, and dust
cover at the disc side and the other spacer and
dust cover from the right side.
Grease and engage the wheel axle from the right
side, fit the large axle nut (plain end inboard) and
secure. There is no washer at this point. At this
stage the motorcycle should be taken off the
stand and, before tightening the fork end clamping
nut the fork compressed a few times to centralise
the fork leg on the axle.
Tighten the pinch nut at the bottom of the right
hand fork slider to clamp it on to the axle. Do not
over-tighten the nut as there is a danger of fractur-
ing the lug.
Front wheel removal
If the fork action is stiff, slacken the axle nut and
the fork end clamping nut and move the forks up
and down to allow the fork tubes to take up align-
ment on the axle. Re-tighten the nuts.
If stiffness still remains, release fender stay bolts
and move forks up and down, finally retightening
the stay bolts.
No adjustment to the brake operating mechanism is
required. Apply the brake several times to refill the
caliper, restore brake pressure, and settle the pads in
correct relationship.
SECTION H7
DISMANTLING FRONT HUB
To gain access to the front wheel axle and bearings,
remove the wheel as described in Section H6. It is not
necessary to remove the brake disc. Proceed as
follows :
1
Extract circlip from right hand end of hub releasing
single-row bearing location.
Heat the alloy wheel hub with hot water only to a
temperature of 100°C.
Insert a bar into the bearing spacer tube and force
the spacer over fractionally. This will provide just
sufficient room to allow a drift to abut on the inner
race of the bearing to be removed.
Using a suitable drift to the bearing inner race
start to drive the single row bearing out. Force the
spacer tube over to the other side of the hub and
tap on the inner race at the new point. Continue
this operation until the bearing is driven out.
Lift out the bearing spacer tube. If this has been
damaged and cannot be corrected, a new spacer
should be obtained for reassembly.
Using a suitable sized drift through the hub
towards the remaining bearing, drive it out of the
hub, taking with it the washers and seal.
Brakes, Wheels and Tires H
SECTION H8
FRONT HUB REASSEMBLY
Prior to reassembly, clean and inspect both bearings,
and components for roughness, wear, damage or corros-
ion and replace as necessary. Proceed as follows:
IMPORTANT
The Mark Ill front hub has been redesigned and
incorporates a single row, rubber sealed, single sided
ball bearing at the right hand end of the hub, sup-
plemented by a bright “flinger” on the distance collar
shrouding the hub centre.
It is important to ensure that a correct type sealed
bearing replacement is fitted with it's sealed side facing
outwards.
1 Tore-assemble, first pack the bearings with grease
(se section K1) then proceed as follows :
2 Press the single row bearing into position at the
right side of the hub, sealed end facing outwards.
3 Fit the circlip, ensuring it is correctly bedded.
4 Insert the bearing spacer from the left, ensuring it
that it is fully home against the single row bear-
ing. Pack the space between the bearing spacer
and hub with grease.
5 Enterthe double row bearing squarely into the hub,
passing the front axle through until it enters the
opposite bearing. Drive the end of the spindle until
the double row bearing comes up against the
distance tube and stops.
6 Fit the felt seal into the hub recess.
7 Insert the longer distance collar and brignt dust
cover-"flinger" into felt seal.
8 The wheel is now ready for fitting.
SECTION HS9
DISC BRAKES (FUNCTION)
Disc brakes function by the pressure of friction pads
gripping a disc which is attached to the wheel hub.
As the brake operating pedal or lever is applied, fluid
from a master cylinder reservoir is forced through the
hydraulic line to the “slave” cylinder in the caliper
gripping the pads against the disc.
The brake requires no adjustment since wear on the
pad is compensated by extra brake fluid passing from
the master cylinder reservoir into the system.
CAUTION:
Replace the friction pads when lining material is worn
to a minimum thickness of 75" (1-5 mm). Should the
brake become “spongy” in operation or acquire exces-
sive pedal (lever) travel, the hydraulic system should
be examined and rectified at once.
SECTION H10
NORTON LOCKHEED HYDRAULICALLY
OPERATED DISC BRAKES
This brake is a very powerful and progressive unit.
The servicing routine is straightforward but it is
absolutely essential for the components of the hydraulic
system to be handled with particular care, avoiding any
Brakes, Wheels and Tires
possible marking of the bores and pistons of the master
cylinder and of the caliper since these are machined to
unusually fine limits. Similarly it is vital to exclude even
the finest particles of dirt and foreign matter from the
hydraulic system and to avoid the use of any fluid or
cleaning agent which could cause even the smallest
degree of deterioration on the rubber seals. Throughout
the following instructions, reference is made to the use
of Lockheed Series 329 Hydraulic Fluid for Disc
Brakes. This is the fluid used by the factory and recom-
mended for use in the Commando disc brake hydraulic
system in subsequent service, the fluid complying with
the requirements of USA/Canada Safety Standard 116.
The hydraulic system is sealed and the master cylinder
and caliper with hose and pipe connected can be
removed as an assembly if required from the rear brake
arrangement without the loss of fluid and without the
need for bleeding on reassembly. Providing the bellows
seal is in situ in the master cylinder there will be no loss
of fluid even from the breather hole in the cap.
The Mark lil Front Brake Hose passes through the fork
middle lug and requires disconnecting if the fork
is dismantled.
IMPORTANT
After rework disturbing the hydraulic unions always
inspect after applying maxinum load and make certain
all joints are again pressure tight. Any witness of seep-
age must be re-examined and rectified before the
machine is used:
It is not necessary to remove the caliper assembly
from the fork leg during renewal of the friction pads as
described below:
Caliper Friction Pad Renewal
1 Remove the front wheel (see Section H6).
2 Rotate the friction pads slightly and remove.
3 Inspect the friction pads for excessive wear.
uneven wear or scoring. If there is any doubt
whatsoever on the condition of the pads, obtain
new pads. kt is important to replace the pads as a
pair: never attempt to replace one pad only.
4 Clean the friction pad recesses and exposed ends
of the pistons using only a small soft brush. DO
NOT utilise any solvent or wire brush for the
removal of dust, dirt or scale.
5 Smear lightly the piston faces and brake pad
recesses with Disc Brake Lubricant.
6 Remove the master cylinder cap and bellows seal
to observe the level which will rise during the next
operation.
7 Press the pistons back into the caliper, observing
the fluid level in the master cylinder to prevent
overflowing. If necessary, excess fluid can be
siphoned off.
If at this stage it is found that the pistons are locked
or seized in position and not free to move, the caliper
must be removed, drained and overhauled as described
later in this section.
8 On motorcycles using the cast iron disc, a rust
build-up may have occurred which prevents entry
of the disc between the new friction pads. Remove
any such rusting by the careful use of a fine flat file.
9 Ensure that the new friction pads are of the correct
friction type to suit the cast iron disc. It is import-
ant to consult the replacement parts catalogue
and thus obtain the correct pads. Frictional and
noise problems will arise if incorrect combinations
of disc and pads are used. Any roughness or
manufacturing flashes must be trimmed from the
edges of the metal backing plate.
CAP SEAL PISTONS
9
f г 9
0 ps =
7
PISTON SEAL FRICTION PADS SEAL
Fig. H6
CALIPER
Exploded view of caliper group
10 Avoiding the friction material, smear the edges of
the pad backing plates with Disc Brake Lubricant
and press fully home against the pistons.
Brakes, Wheels and Tires H
11 Replace the front wheel as in Section H6, support
the motorcycle so that the front wheel spins freely
and apply the front brake lever at the handlebar
several times to restore the fluid in the caliper and
locate the pads correctly.
12 Restore the master cylinder level as in Fig. H7
using Lockheed Series 329 fluid and replace the
bellows seal and cap.
CAUTION: It is dangerous to ride the motorcycle
after pad and hydraulic system attention without first
applying the brake a number of times to restore pressure
and locate the pads to the disc. To avoid glazing of the
friction surfaces, the brake must be applied gently if
possible over the first 50 miles of use.
Caliper Overhaul
It is unnecessary to remove the front wheel but the hose
support bracket must be released from the central fork
mudguard bridge mounting studs and the hose to
bracket clamp nut slackened to facilitate separation of
the hose and pipe from the fork leg. Proceed as
follows:
1 Prior to releasing the caliper from the fork leg,
ease the fit of the caliper end plug which will be
very tight. This will require the use of peg spanner
too! 063965. Do not yet remove the plug.
2 Remove the two caliper bolts and washers and
swing the caliper clear of the fork leg, taking the
weight to avoid straining the brake hose.
3 Lift the two friction pads from the caliper.
4 Brush clean the exposed ends of the pistons and
the outer surfaces of the caliper body, using methyl
alcohol (methylated spirit) if required.
5 Lubricate the exposed ends of the pistons to ease
their passage through the seals.
6 Place a clean receptacle below the caliper to
receive displaced brake fluid and remove the inner
piston. The outboard piston can be removed easily
at a later stage if necessary. For this reason we
recommend the use of a clamp to restrain the out-
board piston. Apply the handlebar brake lever and
the inner piston will be ejected into the friction
pad cavity, and fluid released. Do not use any tool
or airline to remove the piston nor use excessive
pressure at the handlebar if the piston is seized.
NOTE THAT THE ONLY SATISFACTORY REMEDY
FOR A SEIZED PISTON IS RENEWAL OF THE
COMPLETE CALIPER ASSEMBLY.
7 Remove the clamp restraining the outer piston.
8 Slacken the lower brake pipe union nut and
separate the pipe from the caliper.
9 Remove the caliper end plug, drain the remaining
fluid into the receptacle.
10 Remove the piston from the caliper. If there is any
difficulty, push the piston towards the centre of
the caliper and clean carefully the outer working
surfaces of the piston, removing any traces of dirt,
dust or scale with methyl alcohol and/or metal
polish before pressing the piston back into the
caliper body and withdrawing through the end
plug aperature.
11 Using a blunt nosed tool and taking the greatest
possible care not to damage the seal grooves in
any way whatsoever, remove the pressure seal from
the outer bore.
12 Remove the inner piston through the outer
cylinder bore then with the same care remove the
pressure seal from the groove in the inner bore.
13 Pencil mark “Inner” and “Outer” on the friction
material of the pads as applicable for future
reference.
Caliper Component Inspection
Clean the pistons, caliper bores and seal grooves with
ethyl alcohol or clean brake fluid.
Brakes, Wheels and Tires
Examine the pistons and renew if there are any
signs of wear, damage or corrosion. No attempt
must be made to rectify damage wear or “out of
square” thrust faces by machining, filing or polish-
ing. It is permissible only to restore pistons by the
ultimate use of a fine metal polish.
Examine the caliper bores for abrasion, scratches
and corrosion, or damage to the seal grooves. The
caliper bores are not normally subject to premature
failure or wear but irreparable damage can be
caused during removal of damaged or corroded
pistons or careless removal of seals with a sharp
instrument,
After examination clean all the parts thoroughly in
methyl alcohol or clean brake fluid.
Caliper Re-Assembly
Coat the new pressure seals with Lockheed Series
329 Hydraulic Fluid and ease the first pressure seal
into the groove in the inner bore with the fingers,
taking care to bed it correctly. It will be noted that
the diameter of the seal is larger than that of the
seal groove, in order to provide an interference fit.
In addition, the seal groove and seal are different
in section so that when bedded, the seal feels proud
to the touch at the edge furthest from the bore.
This is normal.
Coat the inner piston (the pistons are identical) with
Lockheed Series 329 Fluid, insert it squarely right
through the outer cylinder into the bore of the inner
cylinder, closed end into the bore. Leave the piston
protruding approximately 7% in. (8 mm) from the
mouth of the inner bore.
Fit a new pressure seal to the caliper outer bore
groove, again bedding it correctly.
Coat the second piston with Lockheed Series 329
fluid and insert it open end first into the bore with
the fingers. Avoid tilting the piston and continue
inserting it gently through the bore until approxi-
mately & in. (8 mm) of the open end protrudes
from the inner mouth of the bore.
Replace the end plug using a new '0' ring seal and
tighten into position. For final tightening, the
caliper must be secured to the fork leg.
10
Wipe the caliper clean, removing excess fluid
which may subsequently contaminate the brake
friction pads, taking care not to allow any rag
particles to pass anywhere near the brake pipe feed
union.
Fit the two friction pads and ensure that they seat
correctly.
Assemble the caliper assembly over the wheel disc
and offer the caliper to the fork leg, securing with
two bolts and washers.
Tighten the caliper end plug using peg spanner
tool to 26 Ib./ft. torque.
Refit the fluid feed hose bracket to the mudguard
bridge stud.
IMPORTANT
Before connecting the lower end of the brake pipe to
the caliper, note that the pipe olive is specially formed
to provide an effective high pressure oil seal against the
caliper union seating. The olive is very susceptible to
overtightening and if it is severely distorted by over-
tightening it may be impossible to remove thus render-
ing the caliper scrap.
11
12
13
14
Examine the union olive of the metal brake pipe
for symptoms of previous overtightening such as
distortion, damage and cracks and if necessary
renew the pipe.
Offer the olive of the brake pipe to the caliper, hold
the pipe in the required position and run the union
screw fully down the thread until the pipe is just
“nipped” on to its seating. Tighten the union nut
with a spanner one flat only, i.e. 60°,
Slacken the bleed nipple one full turn and connect
with a suitable bleed tube to a clean container
(see Fig. H8).
Fill the master cylinder reservoir with Lockheed
Series 329 brake fluid.
x .
—
Brakes, Wheels and Tires H
15 Operate the brake lever until fluid begins to flow
through the bleed tube. During this operation,
guard against the master cylinder fluid level
becoming too low, otherwise air will be drawn into
the system. The master cylinder bellows seal must
be removed to observe the fluid level.
if replenishment is necessary during this operation,
hold the lever to the handlebar whilst the reservoir
is topped up. Similarly, when fluid free of bubbles
flows from the bleed pipe, tighten the caliper bleed
nipple, whilst the brake lever is held against the
handlebar.
16 With the bleed nipple tightened up, remove the
bleed hose, apply the brake lever a number of
times to check for sponginess (indicating air still
in the system and a need for further bleeding) and
examine the system for leaks.
17 Finally recheck the fluid level in the master cylinder
reservoir, topping up as necessary, then road test
the motorcycle.
Master Cylinder Overhaul
Prior to commencing work on the master cylinder it is
desirable to obtain a supply of new Lockheed Series 329
Fluid in a sealed container. Where supplies are unob-
tainable and the fluid may have to be re-used, it is sug-
gested that fluid is collected in a clean jar or receptacle
by means of a short length of clean rubber tubing from
LEVER
LEVER PIVOT BOLT
TRAP OR BLETD
ASSE Y
„о
BELLOWS SEAL
Fig. H7 Master Cylinder —Exploded view
the bleed screw to the collecting jar. Release the caliper
bleed screw one full turn and operate the hand brake
lever a number of times until the master cylinder reservoir
is empty. Close the bleed screw and detach the drain
tube. Store the collecting jar safely and cover carefully
to prevent dirt ingress.
Master Cylinder Removal
1 Disconnect the brake stop light pressure switch
spade terminals and lift away the plastic switch
cover exposing the hose union into the master
cylinder.
2 Detach the hose from the master cylinder.
3 Remove the four switch casting screws and lift
away the master cylinder complete.
Master Cylinder Dismantling — See Fig. H7
1 Remove the reservoir cap and bellows seal.
2 Remove the brake light pressure switch.
3 Remove the pivot bolt locknut and withdraw the
pivot bolt and lever.
4 Carefully prise the boot circlip from the lower end
of the master cylinder. This can be achieved if care
is taken to lift three or four adjacent segments
progressively, a little at a time until the circlip is
tipped sufficiently to clear the mouth of the
cylinder bore.
5 The boot is located into the piston and is best
removed with the piston. Lift the piston out com-
plete with boot and secondary cup.
6 Remove the primary cup washer, primary cup
spreader, spring and bleed (or trap) valve
assembly. To dislodge these items it may be
necessary either to bump the casting on a block of
clean soft wood to dislodge them or alternatively to
apply gentle air pressure at the hose union bore
and blow the parts free.
Brakes, Wheels and Tires H
Inspection of Master Cylinder and Components
Discard the primary and secondary cups, the trap valve
and boot. Clean the master cylinder and piston in brake
fluid or methyl alcohol —~ do not use abrasive materials
or solvent fluids.
Inspect the master cylinder body for wear in the piston
bore. Normally, if the seals have been operating satis-
factorily no wear need be expected, but if seal failure
has occurred, the piston may have destroyed the bore
finish. If there is any doubt whatsoever, the cylinder
must be replaced.
If the cylinder is found to be fit for further service,
ensure the two cylinder ports into the reservoir chamber
are perfectly clear and clean. Inspect the hose union
and switch threads for clean and satisfactory condition,
and the lever pivot bolt bore for wear or cracks, or
fractures. Replace the master cylinder if any doubt
exists.
Check the brake lever for pivot bore wear and possible
wear on the piston thrust face. Replace the lever if
necessary. Next examine the piston for signs of scuffing
on the ground outer diameters, and any wear on the
lever thrust face.
Do not attempt to polish or grind the piston in any way,
using abrasive compounds, as the slightest residual
trace of such materials, even after intensive cleansing
will damage master cylinder and caliper working parts
beyond repair, and can result in premature brake failure.
Inspect the brake hose for cuts, signs of leakage or
deterioration. Replace if the slightest doubt exists.
Master Cylinder Reassembly
After inspecting and cleaning the master cylinder, clean
the piston, spring, spreader and cup washer in clean
hydraulic fluid, and place in order of assembly on a
perfectly clean working surface, in a dust free room or
workshop.
DO NOT USE A FLUFFY RAG TO WIPE THE
COMPONENTS. ALLOW TO DRAIN.
Soak the new primary and secondary cups in hydraulic
fluid for fifteen minutes, kneading occasionally to
encourage the special rubber cups to gain their maximum
supple state prior to assembly. Ensure the three relief
holes in the “crown” of the piston are clear and clean.
1
Take the “hollow” secondary cup and place it non
lipped side against the ground “crown” diameter
of the piston. Work the cup over the “crown” by
hand, then down the piston body, over the
shoulder into its groove adjacent to the main body
ground diameter.
CAUTION — Do not use any form of tool to ease
assembly of the cup to the piston for fear of
damage to the lip.
Fit the boot over the piston open end towards the
piston crown and ensure the upper end is fitted
squarely and snugly in the piston groove. The
piston is now ready for assembly.
Assemble the trap valve to the spring, ensuring the
inner plastic bobbin is accurately seated in the
rubber valve base, and that the small diameter
bleed hole in the bobbin base is clear and free.
Ensure the plastic spreader is securely and firmly
pressed home on the other smaller diameter end of
the spring.
La
Offer the spring/trap valve assembly into the master
cylinder, valve end first, keeping the master cylinder
bore upright. It is permissible to hold the nose of
the casting securely in a soft jawed vice, provided
it is in no way overtightened.
Assemble the primary cup washer into the bore,
open end of the cup facing into the bore, followed
by the primary cup washer. Ensure only one cup
washer is employed at this point. Place this
dished primary cup washer, “hump” upwards,
towards the open end of the cylinder bore. (The
effect of the dished cup washer is to close the
primary cup during the return stroke, allow oiling
to by-pass the cup and replenish the pressure
cylinder).
Offer the piston crown first into the cylinder. Place
the 10 eared boot circlip over the top of the boot,
the slight set on the ears facing away from the
cylinder. Ensure fluid is smeared onto the secondary
cup and into the mouth of the cylinder bore.
Brakes, Wheels and Tires H
The next series of operations, to locate the piston,
boot and circlip by means of the brake lever and pivot
bolt can be difficult without the aid of special tools, and
the assistance of a second operator. However, if care is
taken, assembly can be completed without such help,
the difficulty being to locate the base of the boot into
the cylinder counterbore and finally locate and snug
home the circlip whilst holding the piston assembly
within the bore of the master cylinder, against the trap
valve spring, long enough (and with sufficient piston
thrust pad clearance) to be enabled to fit the hand lever
and to locate it with the pivot bolt. The method of
assembling these parts is detailed below:
7 Take the master cylinder assembly in the left hand
(having assembled up to the point as described
above) supporting the casting with the first and
second fingers under the switch boss (hose and
pressure switch threaded bores pointing down-
wards) and left thumb on the top of the casting
close to the piston thrust “pad.” Apply a gentle
rotary action with the right hand to the piston
thrust pad, at the same time maintaining down-
ward thrust pressure against the trap valve spring
assembly — ensuring the lip of the secondary cup
enters the cylinder bore freely and without damage
to the lip. When the piston has entered the bore,
move the left thumb over to maintain the piston
within the bore, at the same time using a blunt
prod to snug the lower boot shoulder into the
cylinder counter bore. Once this is seen to be
achieved, and still maintaining pressure on the
piston thrust pad, work the boot retaining circlip
down to locate and restrain the boot in position.
Still maintaining pressure on the piston thrust pad
with the left thumb, slide the brake lever into posi-
tion at the fulcrum slot, engaging the thrust pad
close to the operator's left thumb. By holding the
lever knob against the chest, alignment of the holes
can be achieved, and the pivot bolt slid into posi-
tion, and located with the locknut.
Master Cylinder Refitting
Refitting the master cylinder is the exact reverse
procedure of the dismantling sequence described above.
Refit the master cylinder to the handlebar, the oil
pressure switch and brake hose. Slide the plastic switch
cover over the hose, hold in a convenient location
whilst the brake light wires are connected to the brake
switch terminals and slide the cover into final location.
Enter the lower hose into the fork support bracket,
locate in position with the locknut and tighten up the
upper brake pipe union nut. Bleed the hydraulic system
as described in the following text, after ensuring that the
master cylinder is level on the handlebar.
Bleeding and flushing the Hydraulic
Brake System
1 Purging of air from a hydraulic system, commonly
known as “bleeding”, should only be necessary
when some part of the system has been dis-
connected, or after the fluid has been drained off
and renewed. However, in normal service, should
the presence of air in the system be indicated by
a spongy’ brake effect, the cause should be
traced and rectified.
Remove the reservoir cap. Remember that brake
fluid ruins paintwork and do not allow fluid to
spill during filling.
WARNING:
Fill the master cylinder supply tank using only brake
fluid to USA DOT 3 specification (Lockheed Series 329
brake fluid Norton Part No. 063111), and keep topped
up throughout the operation, otherwise air may be
drawn into the system, necessitating a fresh start.
2 Attach a suitable length of clean rubber or plastic
tubing to the bleeder screw of the hydraulic unit,
and allow the other end of the tube to be sub-
merged in a small quantity of new fluid contained
in a glass jar. Open the bleeder screw half a
complete turn (Fig. H8). The procedure is the
same for both front and rear brakes.
Brakes, Wheels and Tires H
Apply the brake slowly, allowing it to return
unassisted. Repeat the pumping action, with a
slight pause between each stroke. When stopping
the pumping action such as for refilling the master
cylinder or when clear fluid, free of air bubbles,
emerges from the tube, tighten the bleeder screw
whilst the brake lever is fully pulled to the handle-
bar or in the case of the rear brake, the pedal is
fully depressed.
Verify that the master cylinder supply tank is
replenished to the correct level. FLUID BLED
FROM THE SYSTEM MUST BE DISCARDED-
The above procedure applies equally to front and
rear brakes.
3 Unscrew the bleed screw one full turn and start to
pump slowly the handlebar lever allowing it to
return unassisted. As fluid is forced to the caliper
and through the bleed nipple, the master cylinder
level will drop. Take care throughout the operation
that the level does not drop sufficiently low to
allow further air to be pumped into the system and
top up where necessary.
Fig. H8 Bleeding disc brake hydraulic system
4 Continue pumping the lever until fluid: free of air
bubbles exits from the bleed tube into the fluid
container then hold the brake lever “on” against
the handlebar whilst the caliper bleed screw is
tightened and the bleed tube removed.
5 Test the brake for “sponginess.” If the action feels
“spongy,” then air remains in the system and
further bleeding must be undertaken.
6 Ensure that the master cylinder reservoir is brought
to the correct level then refit the bellows seal and
cap.
USED FLUID BLED FROM THE SYSTEM MUST
BE DISCARDED.
7 Finally check all unions for security and freedom
from leaks.
FLUSHING PROCEDURE
Every eighteen months, or after every 24,000 miles,
whichever occurs first, the fluid in the hydraulic system
should be renewed with the Lockheed series 329 brake
fluid, Norton part number 063111.
Brake fluid, particularly disc brake fluid, absorbs
water from the atmosphere; accordingly, fluid must only
be exposed during the time taken to fill the system. It
is also important that the greatest care is taken to pre-
vent dirt from entering the system during the filling
operation.
Follow the “bleeding” procedure until new clean
fluid emerges from the flexible tube, thus establishing
complete renewal of the fluid.
If the fluid in the system is contaminated by mineral
oil (engine oil) or other spurious fluid, the complete
hydraulic system must be stripped. Hydraulic assemblies
must be renewed or overhauled as detailed in the
workshop manual, and flexible hoses replaced. Further-
more, ensure that all metal fluid pipes are cleaned
thoroughly before reassembling.
REAR BRAKE
Above procedure applies to the rear brake in all
respects.
SECTION H11
REAR BRAKE PEDAL ADJUSTMENT
Adjustment of pedal height is made on the rear master
cylinder piston rod.
Brakes, Wheels and Tires H
1 Slacken the locknut (A) and adjust as required
using nuts B and C which are locked together
during manufacture and which must not, under
any circumstances, be turned in relation to each
other. Disturbing this relationship will alter piston
stroke and may render the brake inoperative. After
adjustment retighten the locknut. See Fig. H9
Fig. H9 Rear brake pedal (exploded) Showing order of assembly and
adjusting nuts.
MOST IMPORTANT
In the event of a rider having the misfortune to “drop”
the machine and damage or distort the brake operating
mechanism (either front or rear) it is imperative he
checks the freedom and correct functioning of the
affected lever or pedal. The rear brake, in particular,
must be inspected and the “eye' and clevis and piston
rod examined before attempting to ride away. Make
sure the cylinder is delivering full pressure and that the
pedal returns freely and unassisted to its correct height
in “repose”. Fig. H9 shows an exploded layout of the
rear brake pedal mechanism and gives a pictorial
definition of the assembly order.
SECTION H12
TIRES
Tire changing is largely a matter of technique and what
to the layman may seem a difficult task is perfectly
straightforward when the correct technique is followed.
To change either tire, the wheel must be removed. See
Sections H688 for front wheelremovaland Section H1 for
rear wheel removal. The same basic principles apply for
all types of tire — lubricate the beadings such as with
soapy water, to allow the beadings to slip easily over
the rim, use heel pressure wherever possible in prefer-
ence to tire levers for easing the tire on to the rim and
minimise the risk of damage by ‘’nipping’ and ensure
that the opposite side of the tire is pressed well into the
rim well to provide maximum freedom where the bead-
ing is being slid over the wheel rim. Note: that the rear
tire only has one security bolt to prevent tire “creep”
such as under hard acceleration. No security bolt is
fitted to the front tire. For this reason separate routines
are given for front and rear tires. The full technique is
as follows:
Removing Front Tire (No security bolt)
1 Remove the dust cap from the valve and using a
suitable notched type of cap or removal tool,
unscrew the valve core to deflate the tire com-
pletely.
2 Remove the knurled ring securing the valve at the
rim. Store the cap, core and knurled ring clean for
re-use.
3 Lay the wheel down, if possible on a clean surface
to avoid scratching and, also to prevent damage to
the front axie. Leave the disc uppermost or place
with disc inside a large 5 gallon drum or bin. This
is common practice in many workshops and pro-
tects disc from damage or distortion. If it is found
that the disc causes obstruction, remove it.
4 Tread the tire beading away from the rim — after a
great deal of service the tire beading has a
tendency to stick.
Brakes, Wheels and Tires H
ha
N172 +
. ” . + : d , ,
Fig. H10 Levering close to valve whilst pressing opposite bea Fig. H11 Two tire levers in use to remove first bead of tire
down into rim
8 Remove the first lever and re-insert at the next
stage, continuing round the rim a little at a time
(see Fig. H11) until the beading can bepulledclear
5 Brush a lubricant such as soapy water onto the tire
beading and rim and also dip the tire levers (two
short ones are recommended) in the solution before
each leverage. of the rim.
6 Insert the first lever between the tire valve and rim 9 Push the valve out of the rim and withdraw the
at the valve position, press the opposite side of inner tube.
the tire down into the rim well and apply leverage
(see F/g. H10).
10 If it is required to remove the tire from the rim,
hold the wheel upright and apply pressure to a
7 Insert the second lever approximately 4 in. (100 lever inserted between the second beading and
mm) from the first and lever the tire beading over wheel rim.
the rim.
It is possible, and some advantage, to hook one
lever under the disc whilst operating with a second
or third lever — thereby using, as it were, a “third
hand”.
Before fitting note that new Avon tires have red and Dunlop tires white paint dots at the lightest
point. Note also that the latest Dunlop tires have directional arrows on the sidewalls. It is most
important to fit the tires with the tread correctly located by the direction arrow.
Fig. H12
Brakes, Wheels and Tires H
Refitting Front Tire (No security bolt)
If the tire has been removed completely, ensure
that the rubber rim tape is fitted properly, rough
side towards and central in the spoke nipple area
of the rim.
Replace the valve core and inflate just sufficiently
to “round” the tube and minimise the risk of
“nipping” at a later stage. Dust the tube with
French chalk and place the tube inside the tire,
aligning the paint dots on the tire with the valve
stem.
Tube within cover squeezing cover to hold valve
protruding
Lay tire and tube over rim ensuring that “front
wheel rotation” arrow (if any) points in direction
of wheel rotation.
Lubricate the beadings with soapy water.
Squeeze the beadings together with the hand, per-
mitting the edge of the tube to protrude for
approximately 2 in. (50-8 mm) at each side of the
valve. Offer the tire and tube to the rim, feeding
the valve through the rim tape and rim holes.
Pressing this side of the tire into the rim well, and
working from the valve, press the first beading over
the rim by hand pressure and lever the last few
inches into position as in Fig. H14. Take special
care that the inner tube is not nipped during this
operation.
Press the second beading into the rim well, starting
opposite the valve then use the heel to press the
bead into position as far round as possible.
8 As shown in Fig. H15, taking care to avoid “nip-
ping”, lever the last portion of the beading over
the rim, finishing at the valve.
9
10
11
Push the valve inwards to the rim to ensure that
the tube near the valve is not trapped between the
beading and rim then pull the valve back and
inflate to pressure.
To ensure that the tire is true on the rim, check the
tire moulded fitting line in relation to the rim. The
position can be cotrected by “bouncing” the side
of the tire on the ground at any point where the
fitting line is too near the rim.
When the tire is fitted correctly, fit the knurled
valve securing rim and replace the valve dust cap.
Removing Rear Tire (Security bolt fitted).
The routine for removing and refitting a tire with security
bolt is basically the same as for a tire without security
bolt but it is important to deal with this item in the
correct sequence. The full procedure is therefore
detailed as follows:
Remove the dust cap from the valve and using a
suitable notched type of cap or removal tool,
unscrew the valve core to deflate the tire com-
pletely.
Brakes, Wheels and Tires
2
5
Remove the knurled ring securing the valve at the
rim. Store the cap, core and knurled ring clean for
re-use,
Unscrew the security bolt nut and push the bolt
inside the cover.
Lay the wheel down, if possible on a clean surface
to avoid scratching.
Tread the tire bead away from the rim — after a
great deal of service the tire beading has a
tendency to stick.
10
11
12
Remove the security bolt from the rim.
Push the valve out of the rim and withdraw the
inner tube.
If it is required to remove the tire from the rim, hold
the wheel upright and apply pressure to a lever
inserted between the second bead and wheel rim.
Fig. H14 First bead being levered into the rim
Brush a lubricant such as soapy water onto the
tire bead and rim and also dip the tire levers (two
short ones are recommended) in the solution before
each leverage.
Insert the first lever between the tire valve and rim
at the valve position, press the opposite side of the
tire down into the rim well and apply leverage (see
Fig. H10).
Insert the second lever approximately 4 in. (100
mm) from the first and lever the tire bead over the
rim.
Remove the first lever and re-insert at the next
stage, continuing round the rim a little at a time
(see Fig. H11) until the bead can be pulled clear
of the rim.
Fig. H15 Careful levering of second bead over wheel rim
Refitting Rear Tire (Security bolt fitted)
1
If the tire has been removed completely, ensure that
the rubber rim tape is fitted properly, rough side
towards and central in the spoke nipple well of
the rim.
~ Ensure “rear wheel direction” arrow (if any), is
pointing in direction of wheel rotation and fit the
first tire beading over the rim without the inner
tube, ensuring that the paint dots align with the
security bolt hole.
Brakes, Wheels and Tires H
3 Lift the free side wall as in Fig. H16 and insert the
security bolt less nut. Loosely fit the leather washer
and nut,
Replace the valve core and inflate just sufficiently
to “round” the tube and minimise the risk of “nip-
ping” at a later stage. Dust the tube with French
chalk and place the tube inside the tire, feeding the
valve through the rim tape and rim holes.
5 Lubricate the bead with soapy water.
/
Fig. H16 Lifting cover and engaging security bolt to rim
6 Pressing this side of the tire into the rim well, and
working from the valve, press the first bead over
the rim by hand pressure and lever the last few
inches into position as in Fig. H14. Take special
care that the inner tube is not nipped during this
operation.
Press the second bead into the rim well whilst
keeping the security bolt pressed back into the tire
as in Fig. H17 starting opposite the valve then use
the heel to press the bead as far round as possible
into position.
As shown in Fig. H,17 taking care to avoid “nip-
ping”, lever the last portion of the bead over the
rim, finishing at the valve.
10
12
Push the valve inwards to the rim to ensure that
the tube near the valve is not trapped between the
bead and rim then pull the valve back and inflate
to pressure.
To ensure that the tire is true on the rim, check the
tire moulded fitting line in relation to the rim. The
position can be corrected by “bouncing” the side
of the tire on the ground at any point where the
fitting line is too near the rim.
Bounce the tire several times in the centre of the
bead where the security bolt is fitted then tighten
the securing nut. Recheck that the fitting line is
still equidistant to the rim.
When the tire is fitted correctly, fit the knurled
valve securing nut and replace the vaive dust cap.
Fig. H17 Pressing security bolt back through rim whilst levering
second bead into position
Nas”
Electrical J
AS,
Electrical
Electrical
SECTION J1
DESCRIPTION
The Commando electrical system is grouped into four
areas for the purpose of this manual. The areas are:
Sections J2 Those parts connected with the charging
to J8: system.
Sections J9 Those parts connected with the ignition
to J14: system.
Sections J15 Those parts connected with the lighting
to J19: system.
Sections J20 Other electrical equipment, including
to J28: the electric starter.
IMPORTANT
Before starting any electrical test procedures, isolate
the warning light unit whichever type is fitted (see
Section J8 for details) by disconnecting the green/
yellow lead to the unit at the alternator green/yellow
lead double snap connector.
The Commando electrical system is positive earth
(ground).
SECTION J2
CHARGING SYSTEM
The charging system comprises an alternator with the
6 charging coils connected permanently (fitted in the
primary chaincase and driven by the engine crankshaft).
This supplies alternating (A.C.) current to the rectifier
where it is converted to half-wave direct (D.C.) current.
The D.C. current is fed to the lead/acid battery in parallel
to the Zener diodes which are mounted on the left and
right support plates for the silencer and footrests, one
each side of the machine.
The function of the Zener diodes is to regulate the
flow of D.C. current and thus prevent overcharging of
the battery. Surplus current is directed to the heatsinks
(in this case, the light alloy support plates for the
silencers and footrests) where it is dissipated as heat.
J
The increased output of the RM23 alternator (now
producing 15 amps at 6,000 r.p.m.) has prompted the
use of two regulating Zener diodes in the charging
system,
The rectification still follows a basic push-pull
“bridge connected” layout but the two earthed diodes
are replaced by Zener diodes, moved apart and earthed
separately.
When the system voltage is below approximately 13
volts, the Zener diodes operate as ordinary semi-
conductors and the full output from the alternator is
supplied to the battery and loads.
As the system voltage rises the Zeners by-pass the
excess current having become conductive in the reverse
direction. See Section J15. In this operating condition,
during part of one half cycle, one Zener operates in the
reverse direction, the other in the forward direction.
The opposite occurs in the next half cycle. As a
consequence of the above it is unnecessary to match
the Zener diodes, any combination within commercial
tolerances will be satisfactory.
The high output of the RM23 js thus shared between
two Zeners and two heatsinks, the system is working
within moderate limits at all times, giving improved
reliability and increased component-life to the equip-
ment.
IGNITION SYSTEM
The Commando Mk lil is equipped with a 12-volt
electrical system but uses 6 -volt ignition coils, protected
behind a ballast resistor, ensuring an adequate spark
intensity even under adverse conditions.
Should the battery fail completely the electrolytic
capacitor will provide starting, ignition and direct
lighting (parking lights excepted).
Below are detailed the components of the charging
system with applicable test procedures :
Electrical
Alternator
RM. 23
Rectifier Double Diode
Model 2DV 406
Lucas Part No. 49181
The diode in each ZENER, still operates as a ‘one-way’ rectifier
but, because it can open up and become conductive above
12.75 volts, each releases excess on one wave alternately, thus
providing the necessary rectification, but with a ‘regulation’
bonus.
The advantage of the system is the halving of the load (split
'50/50') between each ZENER as compared with the previous
full wave system.
>
HE e
Zener Diodes Ñ.. o 2-1.
Model 2D 715
Lucas Part No. 49345
«ре ,
Fig. JI.
SECTION J3
ALTERNATOR —- LUCAS TYPE RM23
The alternator produces an alternating current (A.C.) by
means of a six-pole permanent-magnet rotor which
rotates within a stationary six-pole laminated-iron stator
assembly.
The rotor is attached to the engine crankshaft, which
revolves at engine speed. The stator sub-assembly,
comprising the windings and laminations, is mounted
on an outrigger plate (which also provides a bearing
for the new electric starter gear train) and supported on
four studs which clamp the inner primary cover to the
drive side crankcase.
Maintenance
The alternator and associated equipment requires no
maintenance except for an occasional check tó ensure
that all the external cable connections are clean and
tight. The rectifier mounting is no longer in essential
electrical contact. If it should be necessary to remove
the alternator rotor from the engine crankshaft, the use
o.
Loads
Mark III Commando Simplified Diagram of Half Wave Rectifier and Twin-Zener System
of magnetic keepers is not necessary, but keep the rotor
away from magnetically-attracted metal foreign matter.
Mk 111 Commando — Electrical System Loads
The following table lists the electrical loads on the
Mk Il! Commando:
Amp
1 Ignition (running) — approximate 2:5
2 Main beam (60W Q-H-45W) 5-0 or 3-8
3 Dip beam (55W Q-H-+40W) 4-6 or 3-3
4 Pilot bulb (5W) 0-4
5 Tail bulb (5W) 0-4
6 Speedometer bulb (3W) 0-3
7 Tachometer bulb (3W) 0-3
8 Ignition warning light bulb+ circuit 0-1
9 Main beam warning light bulb (3W) —
10 Direction indicator warning light bulb (3W) —
11 Direction indicator bulb pair (21W each) 3-5
12 Stop lamp bulb (21W) 1-8
13 Horn — typical value 35
14 Neutral indicator bulb (3W) —
15 Electric start solenoid (approximate) 3:0
16 Electric starter up to 260A peak
(dependent upon engine state and temperature)
Electrical
Testing the alternator in situ
(a) Disconnect the alternator leads at the snap con-
nectors.
(b) Connect an A.C. voltmeter (with 1 ohm resistor in
parallel) as detailed in the table below. See Section
J25 for instructions on making a 1 ohm resistor.
(c) Start engine and run at approx. 3,000 rev./min.
noting voltmeter readings.
MINIMUM VOLTAGE
READINGS
VOLTMETER AND RESISTOR
ACROSS Stator: Two lead
Type: RM23
White/Green. Green/Yellow 9
Any one lead and stator earth NO READING
(ground)
CONCLUSIONS:
If the reading is low, check the rotor by substitution.
Zero reading indicates open -circuited coil(s).
Testing the D.C. input to battery
(a) Connect a D.C. ammeter in main battery lead
(between battery negative terminal and battery
cable), red lead to cable, black lead to battery
terminal.
alternator
Fig. J2
(b) Ensure Zener Diodes are connected normally.
(c) Start engine and run as shown in table.
The following reading will be obtained if the battery
and charging systems are in good condition.
Minimum
Switch Position Current Reading Engine r.p.m.
Ignition and Lights
(Main Beam)
Filament Bulb
0-5 Amp 3,000
Ignition and Lights
(Main Beam)
Q.H. Bulb
0-5 Amp 3,500
CONCLUSIONS:
If the readings obtained are higher than the figures
quoted, the system is satisfactory. If the readings are
lower, proceed to test the alternator itself as in the
preceding text.
SECTION J4
RECTIFIER TYPE 2DV.406.
The rectifier, which is of the silicon crystal bridge-
connected half-wave type, requires no maintenance
beyond a periodic check on the cleanliness and security
of the terminals. If for any reason the rectifier is
removed, DO NOT twist the plates in relation to one
another since this will break internal connections and
render the rectifier unfit for further service. The centre
bolt must be held with a spanner whilst the fixing nut is
one ohm
resistance voltmeter
mm ay —
WG TNS
Alternator test
Electrical
turned. This bolt is now insulated from the circuit and
no longer needs to make electrical contact with the
frame. Never disturb the nut clamping the plates
together; these are pre-loaded by the manufacturer to
give correct performance. The rectifier is accessible
when the seat is lifted.
Testing the rectifier
Testing the rectifier in circuit is no longer a straight -
forward procedure as the Zener diodes form part of the
rectification function.
However, a bench test is feasible and quite satis-
factory .for confirming a faulty unit.
The method is as follows:
Bench testing the rectifier
Connect a 12 volt, 45-50 watt bulb and 12 voit battery
battery 12 volt
0 0 0% © oO o
Fig J3
SECTION J5
Zener Diode
The Zener Diode is a semi-conductor device that
becomes conductive in the reverse direction at a critical
but predetermined voltage.
Assuming the battery is in a low state of charge, its
terminal voltage (the same voltage is across the diode)
will also be low, therefore the maximum charging
current will flow into the battery from the alternator. At
first none of the current is by-passed by the diode, the
headiamp
bulb
across terminals 2 and 1 (for a period not exceeding 30
seconds). See Fig. J3.
Repeat test with reversed battery polarity.
Carry out similar tests on terminals: 2 (center
terminal) and 1, 2 (center terminal) and 3, repeating
with opposite polarity, i.e. reverse the connections.
The test lamp should illuminate fully in one direction
only for each of the connections made.
CONCLUSIONS:
Rectifier must be replaced if :
(a) Bulb shows sign of illumination in for each
both direction connection
(b) Bulb shows no sign of illumination made. '
in either direction
rectifier
Bench testing rectifier
latter being non-conductive due to the low battery
terminal volts. However, as the battery voltage is
restored, the system voltage rises until, at approximately
14 volts, the Zener diode becomes partially conductive,
thereby providing an alternative path for a small part of
the charging current. Small increases in battery voltage
result in large increases in Zener conductivity until, at
approximately 15 volts, about 5 amperes of the alternator
output is by-passing the battery. The battery will con-
tinue to receive only a portion of the alternator output as
long as the system voltage is relatively high.
Electrical
Depression of the system voltage, due to the use of
headlamp or other lighting equipment, causes the
Zener diode current to decrease and the balance to be
diverted and consumed by the component in use. If the
electrical loading is sufficient to cause the system volt-
age to fall below approx. 14 volts, the Zener diode will
revert to its high resistance state of virtual non-
conductivity and the full generated output will go to
meet the demands of the system.
In the event of one Zener failing open circuit — i.e. if
itis continuously conductive, it produces a short circuit.
If the system is to be run in daytime (no lights) leave
the shorted Zener diode connected until replaced. The
reduced output which is still regulated by the other
Zener diode would be adequate for daytime loads.
For night-time running (with battery) the shorted
Zener diode should be disconnected thus obtaining a
greater but unregulated output.
When operating without a battery the diode must
not be disconnected as the system voltage could rise
excessively with serious consequences, “blowing
bulbs, etc.
A rough guide to a failed Zener diode is provided
by the heatsinks. Correct balance is shown by approxi-
mately equal temperatures at the heatsinks.
Fig. J4
When refitting a Zener diode (or if either unit is
disturbed) the contact between the diode and the
heatsink must be clean and free from corrosion. The
tightening torque for the retaining nut is 24-28 Ib./ins.
(3-32-3:87 kg/m). In addition the seating face must
be true and free from burrs. It is most important that
the earth lead is not fitted between the face of the Zener
diode and the footrest plate.
Bench testing a Zener Diode
Using any convenient D.C. current source with variable
control, e.g. two 12-volt batteries, fully charged, con-
nected in series, feeding via a suitable rheostat. See
Fig. J4.
1 Connect a D.C. ammeter (0-5 amps min.) in
series between the Lucar terminal of the Zener
diode and feed cable. (Red lead to Zener, Black
lead to cable.)
2 Connect a D.C. voltmeter (0-18 volts min.)
between the Lucer terminal of the Zener diode and
earth (ground) on the heatsink, which is earthed
to the batteries. Red lead to earth, Black to the
Zener lucar blade.
VARIABLE (24 volt)
SOURCE
``
RHEOSTAT
Bench testing a Zener Diode. Showing ammeter and
voltmeter connections for test purposes
Electrical
3 Gradually increase the current feed via the Rheo-
stat, whilst observing both meters:
(a) The series connected ammeter must indicate zero
amps, up to 12:75 volts which will be indicated
on the shunt connected voltmeter as current is
increased.
(b) Increase current still further until lower current
indicated is 2-0 amps. At this value the Zener
voltage should be within 13-5 volts to 15-3 volts.
TEST CONCLUSIONS
If the ammeter in test (a) registers any current at all
before the voltmeter indicates 12:75 volts, then a
replacement Zener diode must be fitted.
If test (a) is satisfactory but in test (b) a higher
voltage than that stated is registered on the voltmeter
before the ammeter indicates 2:0 amps, then a replace-
ment Zener diode must be fitted.
SECTION J6
BATTERY - ELECTRICAL
A single, compact, 12-volt, high-efficiency lead acid
battery with ultra-high discharge rate, is now fitted to
the Mk Ill Electric-start Commando.
The makers of the YUASA YB14L have developed a
uniquely thin separator using a specially treated, micro
porous, plastic membrane; permitting nine plates per
cell to be accommodated in this remarkably compact
unit.
The battery acid is visible through the casing and
the electrolyte level is clearly marked on the case. A
breather vent is fitted. The vent is totally sealed during
transportation and pre-service storage, to avoid
deterioration of the plates, but must now be opened to
atmosphere before filling the cells with electrolyte.
J
Table 1 Maker's Data: Battery Capacity
Battery Type YB.14.L
Voltage 12 volts
Capacity (at 10 hour rate) 13 amp/hour
Normal Charging Current 1:3 amps
Total Volume of Electrolyte 0-81 liters
Specific Gravity at 20°C (68°F) — Tropical 1-240
Specific Gravity at 20°C (68°F) — Temperate 1-280
Initial Charging
With the introduction of electric starting the demand
on the battery has increased the need for careful initial
servicing, and to ensure maximum performance and
life the recommended routine should be strictly
observed, as follows:
1 Remove sealing plugs and vent seal from elbow.
Fit vent pipe securely to elbow.
2 Fill each cell to "UPPER LEVEL” as marked on
the case. Use dilute sulphuric acid. Make sure its
temperature is below 30°C/86°F and the specific
gravity (strength) is correct as follows:
REQUIRED SPECIFIC GRAVITY AT 20°C/68°F
Tropical climates normally above
25°C/75°F 1-240
Temperate climates normally below
25°C/75°F 1-280
3 Leave battery to stand for 12 hours (previous
instructions have stated minimum half hour). For
optimum battery performance, the factory has now
recommended this increased soak-period.
4 "Top-up” as required with above strength electro-
lyte.
5 CHARGING TIME:
The charging time needed by a new battery is
determined by the number of months that have
elapsed since manufacture. The date of manu-
facture is printed on the tape enclosed with the
vent plugs. The following table confirms recom-
mended charging times relative to age since
manufacture.
`
Electrical
Table 2
Within | Within | Within | Over
Months after manufacture 6 9 12 12
Necessary Charging Hours 20 30 40 60
6 Charge continuously at 1-3 amps for the recom-
mended time. As the charge “comes up” the
voltage and specific gravity of the electrolyte
attain their correct level and become constant.
but still continue the charge for about 3 more
hours with the same current after they have
stabilised.
7 Near the end of the charging period, adjust the
specific gravity of the electrolyte to the value
shown in Table 1. After charging is completed
top up to UPPER LEVEL with DISTILLED WATER.
8 Replace vent plugs. Wash off acid spillage with
water. Dry off the battery.
Battery Mounting
For access to the battery, remove the left side cover by
giving one half turn on the slotted fastener at the
bottom of the left side cover using a coin or similar
object, lifting the seat on its hinge then removing the
panel up and forwards clear of the locating pegs.
To remove the battery, pull down on the battery strap
buckle to disengage it from the battery carrier hook.
Disconnect the heavy duty starter lead and red lead
from the “+” terminal and the brown/blue lead from
the “—” terminal on the battery. Slide the vent pipe
clear. Lift out the battery, taking care not to spill acid.
When refitting, turn the battery so that the terminals
are towards the rear of the motorcycle. If the tension
on the battery strap is insufficient, the strap can be
tightened through the buckle before the buckle is
hooked on to the battery tray. The electrolyte level can
be seen embossed on the battery casing without
removal.
Battery Maintenance
Due to continual evaporation and gassing during
charging, a two-weekly inspection must be made on
the electrolyte level. Since the level will normally rise
whilst the battery is being charged, the level must only
be checked during off-charge periods. Any loss of
electrolyte should be made good by the addition of
distilled water until the level mark is reached. The level
should not exceed this mark, for spillage may occur with
subsequent damage to surrounding parts.
It is important to keep the battery connections clean
and tight with the positive lead -| always connected
to ground (earth). Dirt and moisture must be wiped
away from the battery top periodically.
If the motorcycle is stored for a period, the battery
should be removed and maintained in a good state of
charge every two weeks, with a short refreshing charge
at 1 ampere.
CAUTION:
Do not use a naked light when inspecting the battery
during charging. Because the gases given off are of an
explosive nature. Always ensure the breather pipe is
clear of the frame and not trapped, and connected to
the battery.
Never use tap-water to top up as this may contain
salts harmful to the battery.
The battery terminals must never be reversed other-
wise the equipment will be damaged. Red must be
earth/ground: Brown/Blue live wire.
Service Life
When material falling from the grids almost fills the
sediment space below the plates the service life is over.
“If the battery is left in discharged condition and plates
have become white, it will no longer be serviceable.
Electrical
Checking the state of charge
A very small capacity hydrometer is required for this
check (each cell contains 133 cc of electrolyte only).
The specific gravity should be checked for each cell
and the results checked with the table below:
Table 3
SPECIFIC GRAVITY
(Corrected to 15°C (60°F) )
Climates normally | Climates normally
below 25°C above 25°C
(77°F) (77°F)
Fully Charged 1-270 - 1-290 1-230 - 1-250
70% Charged 1:230 — 1:250 1:190 — 1:210
Discharged 1110-1130 1-070 - 1-090
Electrolyte temperature correction :
For every 10°C (18°F) below 15°C (60°F) subtract
0-007.
For every 10°C (18°F) above 15°C (60°F) add 0-007.
A variation of more than 40 points (0-040) between
any cells indicates that the battery is suspect and should
be thoroughly checked by the battery manufacturer's
agent.
High rate discharge check
(Battery must be at least 70% charged).
Connect voltmeter and high rate discharge resistance
(0:5 ohm) across battery terminals for 15 seconds.
Directly after 15 seconds the reading should remain
steady.
A lower or rapidly falling voltage indicates the battery
requires charging or has a faulty cell.
BATTERY VOLTAGE VOLTMETER READING
12 9-4
sn ><
o WE
© —? one
o Cc ohm voltmeter
5 9 load
O “eo
O
I (abe
Fig. J5 High rate discharge test
Running with battery disconnected
Before running with the battery disconnected always
insulate the negative (brown/blue) live lead to prevent
shorting to earth on any part of the machine.
SECTION J7
WIRING
Cable Harness
The cable harness requires no maintenance beyond
checking that there are no signs of chafing along its
length, especially around the steering head where the
harness is continually flexing. The harness must not
be stretched at any point and the terminals must be clean
and tight.
Fused Battery Lead
A fuse is fitted in an in-line fuse holder incorporated
in the battery live (negative) lead close to the battery
terminal. The fuse is of the cartridge type, in a nylon
holder. If this fuse fails, it indicates a fault in the
electrical system (such as a short-circuit). The cause
of failure should therefore be ascertained before fitting
a replacement fuse.
Access to the fuse is gained by pushing the fuse-
holder body halves together and twisting. At no time
must the value of 35 amps be exceeded.
Electrical
The correct rating of the fuse is 35A. This rating must
not be exceeded, neither must the fuse holder be
by-passed to overcome fuse failure.
NOTE: When refitting the battery, ensure that the fused
lead is not stretched to reach the battery terminal, as
this may cause an open circuit at the fuse holder.
SECTION J8
WARNING LIGHT UNIT
Early Mk I! Models
Should the warning light fail to light when the ignition
is switched on and with the engine stationary, discon-
nect the White/Brown lead from the “W L” terminal of
the control unit and temporarily reconnect to the “E”
terminal ; if the bulb lights, this indicates that the control
unit is faulty, but should the light still fail, then the bulb,
connections, and associated wiring should be checked.
Warning Light Unit: Current Models (except
Canada) :
The former electro mechanical Lucas 3AW (Warning
Light Simulator fitted on early electric starter Mk 1
models) has now been replaced on all models (except
Canada) by a solid-state encapsulated Warning Light
Control 06-6393.
When the ignition is switched on the warning light
is illuminated and as engine revolutions increase the
light goes out, confirming the system is working.
Automatic “Lights-on’’ (when running) Canada:
Canadian legislation now requires (on all machines
manufactured after 1st January 1975 and imported into
Canada) that the headlamps must be illuminated
WHENEVER THE ENGINE IS RUNNING.
To meet these requirements a fully encapsulated
device is now fitted which overrides the main switch
J
and automatically illuminates the head and tail lamps
even though the switch is in the “ignition only”
position.
In addition a new Lucas master switch No. 30825
(Norton No. 06-6625) is introduced, replacing Lucas
No. S149A and incorporating a revised connection in
the OFF position. This does however switch on the
pilot lights in the IGN position before starting the
engine, but presents no problem in practice, as the pilot
lights illuminate automatically immediately the engine
starts.
See Fig. J6 for switch modes and functions.
Do not attempt to utilise the original switch in con-
junction with this circuit.
Re-connect the new switch exactly as previously.
Failure to do this will create incorrect external switch-
ing problems.
As the engine starts the red warning light dims and
remains a warning “glow”, reminding the rider that in
this position of the switch his lights are “on” but are
receiving direct alternator current only. This is accept-
able for daylight running but when the engine revolu-
tions drop — e.g. at traffic lights or when going slow —
it is undesirable in darkness.
When the warning light is glowing, especially after
dark, we strongly advise always moving the switch to
“head” to feed in the main D.C. (battery) lighting
circuit and maintain full brightness (especially of the
tail lamp), in slow traffic or when halted and idling in
darkness.
“Lights-on”” Conversion Mk [11 Commando
Where it is necessary to convert an early Mk II! model,
the following action should be taken:
Remove battery cover, battery and fuel tank. On
early electric starter Mk III models, remove the Lucas
type 3AW part number 38717 ignition warning light
simulator complete with spring from the rear frame
gusset plate. On later models, remove the encapsulated
ignition warning light control device, part number
06-6393 from the battery tray (taking care not to drop
the bolt), and replace unit with the new headlamp
warning unit, part number 06-6392.
Electrical
Ignition W/L Control Unit Simulator
original connections
Harness Wire Code Terminal Connection
White W IGN
*Green/Yellow GY AL
*White/Green WG AL
White/Brown WN WL
Red R E
Ignition Switch
Rectifier
Rectifier
Warning Light
Earth (ground)
H/L Warning Unit connections
Harness Wire Code Terminal Connection
Brown/Green NG TL Tail Light
Green/Yellow GY AL Rectifier
*White/Green WG AL Rectifier
*White/Brown WN WL Warning Light
Blue U HL Head Light
Redundant wires (IGN and earth (ground) must be
carefully insulated and securely taped back to the
harness for protection). The required conversion wires
will be found in the harness on later Mk Ill! models.
"On early models, where ignition warning light
simulator (Lucas part number 38717) was fitted, the
rectifier leads are not included in the wiring harness.
To fit the headlamp warning unit, the additional con-
necting wires will have to be made up and adapted.
To complete the conversion a new master switch
No. 30825, Norton No. 06-6625 should be fitted and
reconnected on identical contacts.
SECTION J9
MASTER SWITCH
The four-position, key operated switch, with waterproof
cover, is located in the warning light console. The
switch controls ignition and also energises the lighting
system. The switch is a sealed unit requiring no
attention other than a routine check on connections.
The four switch positions are shown below in Fig. J6.
The four Switch Positions are:
1. Parking Lights Only (Ignition off)
The key may be removed in this position enabling
the machine to be parked safely at night.
2. Off Position
Again the key may be removed leaving all circuits
isolated. (Lights and Ignition off.)
3. Ignition Only: Ignition and Parking Lights engine
stopped: (Canadian models): Ignition and Main
lights: engine running (Canadian models).
The key cannot be removed. This position is used
during normal daytime running, not at night.
See “Lights-on" electrical equipment. (Appendix
to Section J8.)
4. Ignition and Lights (All Markets)
Again the key may not be removed. This position .
is used for night riding.
The lock with keys is captive in the switch body. If
for any reason the lock needs to be replaced, it can be
removed from the switch body to which it is held captive
by a spring operated plunger. À sharp pointed implement
such as a ground-down spoke would be ideal for
depressing the plunger through the hole in the side of
the switch body. Whilst depressing the plunger the
switch body should be shaken and the lock ejected.
OFF
ALL MARKETS
(KEY REMOVABLE )
IGNITION ONLY
REST OF WORLD
(IGNITION AND LIGHTS
CANADIAN MODELS ONLY
KEY CAPTIVE)
ALLMARKETS
(KEY REMOVABLE)
IGNITION AND
LIGHTS
ALL MARKETS
(KEY CAPTIVE)
Fig. J6 Master switch positions
Electrical
CANADIAN MASTER SWITCH: Modes and Functions
Mk II} Commando for Canada with Master Switch 06-6625 and Headlamp Warning Unit 06-6392
Connecting
Contact Points —
Switch Wiring Diagram Current
Position JOO Source Function
1 Park 1-3 Battery Pilot lights and instruments - ON
2 Off None — OFF. All electrical circuits disconnected.
"3 Ign. 1-2-3 Direct from Pilot lights, instruments, warning lights and ignition — ON.
Alternator "Headlamp when engine runs.
t Brightness varies with speed.
Ignition warning light varies inversely with speed.
"4 Ign. & Lights 1-2-3-4 Battery (a) Handlebar light switch on PILOT, function as 3.
(b) Handlebar switch on HEAD. Head, tail, instruments and
w arning lights ON.
Headlamp brightness constant.
Ignition Warning Light ceases to function.
When engine stops, Headlamp remains on, Ignition Warning
Light remains off.
"Headlamp Dip Switch functions normally on 3 and 4.
*Indicating need to switch to position 4 (HEAD).
SECTION J10
TESTING IGNITION SYSTEM
Testing Sequence for Ignition System
Engine ; will not start — difficult to start — misfires.
(a) Check battery.
(b) Check main fuse
(c) Check for spark at both spark plugs.
(d) Ensure timing, contact breaker and spark plug gaps
are satisfactory.
(e) Check capacitor by substitution.
(f) Check wiring for loose connections.
(g) Test Zener Diode and ignition system.
(h) Check ballast resistor for short circuting, when
hot.
(1) М.В. Engine fires but will not run. Check position
of “kill button”. It may be in the off position.
Ignition System Tests
(a) Connect D.C. voltmeter Black lead to C.B. terminal
of contact breaker and Red lead to earth.
(b) Ensure contact points are open.
(c) Switch on ignition. Voltmeter should indicate
battery volts.
(d) Ignition still on, close contact points. Voltmeter
reading should fall to zero.
Note: Repeat the test for each coil with its appropriate
contact set.
CONCLUSION:
No reading for test (c) may indicate faulty ignition
switch, open circuit primary winding, broken lead, short
circuit to earth on C.B. lead, faulty capacitor or blown
main fuse.
Low reading indicates high resistance in the primary
circuit or across ignition switch contacts. A reading for
test (d) indicates voltage drop across the contact points
(dirty) or poor distributor earth.
Electrical
SECTION J11
IGNITION COILS
The ignition coils consist of primary and secondary
windings wound concentrically about a laminated soft
iron core, the secondary windings being next to the
core.
The primary winding usually consists of some 300
turns of enamel covered wire and the secondary some
17,000 — 26,000 turns of much finer wire — also
enamel covered. Each layer is paper insulated from the
next in both primary and secondary windings.
When the contact breaker opens, causing a sudden
cut-off of current flow in the primary windings, H.T.
current is induced in the secondary windings and a
spark occurs at the spark plug.
Note: The coils are of the oil filled type and must be
protected from mechanical damage which will cause
leakage.
IGNITION COILS LUCAS TYPE 17M6 (6 VOLT)
Six volt ignition coils are used in conjunction with a
ballast resistor to allow their use in an otherwise 12 volt
electrical system. This system has been adopted to
ensure an adequate spark with the battery in a heavily
discharged state. The ignition coils are sealed units,
requiring only a periodic check oh connections. -
TESTING AN IGNITION COIL
An electrical test set is necessary for full testing of the
ignition coil and though a similar set-up can be
IONISING
ELECTRODE
IGNITION COIL =
— —— Pl — A бен EE — —: -
HT 5
TERMINAL CB.OR+V
TERMINALA—— 565 -— |
TERMINAL , ,
SW.OR-VE | °° 1
Nt13
Fig. J7 Ignition coil testing arrangements incorporating 3 point test
CONTACT BREAKER
UNIT =
7 Y 1
J
produced as shown in Fig. J7 provision will have to
be made for a contact breaker which can be motored at
100 r.p.m. Use a 6 volt battery for this test.
Before commencing the main test, check the condi-
tion of the primary windings. This is done by connecting
an ohmeter across the low tension terminals. At 20°C
the minimum resistance should be 1:7 ohms and maxi-
mum resistance, 1-9 ohms for 17M6 (6 volt) coils.
Set the adjustable gap to 8 mm for the 6 volt coil
and connect up as in Fig. J7. If the coil is in good
condition, sparking should occur regularly with no more
than 5% missing per 15 seconds.
SECTION J12
BALLAST RESISTOR
(With 6 volt coils)
The ballast resistor is fitted across the front of the coil
mounting and permits the use of 6 volt coils in an
otherwise 12 volt system. The two coils are wired in
parallel with the resistor in series. When the battery
voltage has dropped due to the heavy current taken
such as by the use of an electric starter, the ignition
coils are fed direct, by-passing the resistor and thus
enabling the coils to work at their approximate potential.
The ballast resistor can only be tested against its
resistance value of 1-8-2 ohms, and requires no main-
tenance except an occasional check on the security and
cleanliness of the terminals.
CONTACT BREAKER ASSEMBLY —- LUCAS
TYPE 10CA
The contact breaker and auto advance mechanism are
covered fully in Section C39 & C40 adjacent to engine
ignition timing details.
SECTION J13
CONDENSER (CAPACITOR) PACK TESTING
The two condensers (capacitors) are mounted in a
“tandem” pack (LUCAS RCP) behind the baliast
resistor on the coil cluster bracket. The rubber cover
Electrical
is easily removed to gain access to the individual
capacitors. The capacitors can be tested in situ. To
test, turn on the ignition and take voltage readings
across each set of contacts when open. If no reading
is gained, the capacitor is unserviceable due to a break-
down of the internal insulation. If a reading is gained
but the capacitor has reduced capacity, evidenced by
excessive arcing and severe burning of the contact
points, a new capacitor should be substituted on the
affected cylinder.
CHANGING A CONDENSER (CAPACITOR)
PACK
Remove the complete coil cluster (see Section C1)
Release the capacitor pack (2 screws and nuts).
Remove the rubber cover: the individual capacitors are
retained to the base plate by single nuts.
Reassembly is a direct reversal of the foregoing. Take
care to reconnect the wiring correctly. If necessary
consult the wiring diagram at the end of this section.
EMERGENCY START CAPACITOR
(Batteryless running)
ELECTROLYTIC CAPACITOR 2MC (Fig. J8)
The capacitor is an electrolytic polarised type, spring
mounted to the rear of the battery. This unit will be
damaged beyond repair if it is connected incorrectly.
The small (+ in.) terminal is the Positive ground (earth)
terminal with a red spot on the termina! rivet. The double
terminal is the Negative connection. The capacitor
should only be fitted with the terminals pointing down -
wards. The battery may be removed altogether or be
completely discharged whilst the 2MC capacitor per-
mits normal starting and running. With the capacitor in
use, the lights may be used whilst the engine is running
though there is no parking facility.
Periodically the capacitor should be tested by dis-
connecting the battery terminals — the negative terminal
should be insulated to prevent a possible short circuit.
Start and run the engine — full lighting should be avail-
able. If the engine fails to start and run, test as follows:
(a) Disconnect capacitor.
(b) Connect capacitor direct to 12 volt battery for 5
seconds (see polarity note).
(с) Disconnect battery and let charged capacitor stand
for 5 minutes.
(d) Connect D.C. voltmeter across the terminals (see
polarity note) and note the steady reading * which
should not be less than 9v for a serviceable unit.
J
*Some meters may show immediate needle overswing
which should be ignored.
Polarity note: 2MC capacitors are polarity conscious
and correct battery connection must be made. The
smaller Lucar terminal blade (rivet marked red), is posi-
tive and the larger double Lucar connector torms the
negative terminal.
Conclusions:
If meter reading is less than 9v, capacitor ts leaking
(inefficient) and must be replaced.
PREF PEF Faring ,
зна "JAI réa FETES
eg +
rid
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rey
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Fig. J8 2MC Capacitor.
SECTION J14
SPARK PLUGS - CHAMPION N7Y
Protruding nose self-cleaning spark plugs are fitted. It
is most important to use the correct heat grade since a
spark plug of too low heat grade can cause pre-
ignition and subsequent damage to the engine.
To avoid damage to the insulator, use the plug spanner
provided in the tool kit to remove and refit the spark
plugs. The spark plugs should be tightened firmly (not
excessively) to ensure a gas tight joint.
When adjusting the gap to the recommended setting
of -028 in. (-59/-72 mm), only the side contact must be
adjusted. Under no circumstances attempt to bend the
centre electrode to adjust the gap.
SECTION J15
LIGHTING SYSTEM
The lighting system operates on direct current drawn
from the battery (or from the rectifier where the 2MC
capacitor replaces the battery) and controlled by the 4
position master switch (described in Section J10). As
the master switch is turned to the “lights on” position,
the tail lamp, instrument lights and pilot lamp illuminate.
Selection of headlamp illumination is controlled by the
Electrical
switch in the warning light console. Headlamp high
beam or dip beam are selected by the two position
switch included in the handlebar left switch cluster.
When high beam is selected, a warning blue light in
the instrument console illuminates.
All Canadian machines manufactured after 1st Jan.
1975 require lights-on when engine is running - See
Section J8.
SECTION J16
HEADLAMP (SS700P or MCHes6)
TO CHANGE THE HEADLAMP AND PILOT
BULBS
Release the screw on top of the headlamp shell
adjacent to the rim. The rim with light unit can then be
lifted out from the top first. Press down the main bulb-
holder towards the reflector and rotate counter clock-
wise. The holder will lift away and the bulb can be
removed. On quartz-halogen and Continental head-
lamps pull the adaptor free of the bulb and release the
retaining clip to remove the bulb.
The pilot bulbholder complete with pilot bulb should
be pulled away from the light unit. The bulb is a bayonet
fitting into the bulbholder.
Note: Do not touch a quartz halogen bulb envelope
with the fingers. Accidental marks can be removed with
alcohol.
BULBS
Conventional filament bulbs:
U.K., U.S.A., Canada Type 370
Continental (not France) Type 410
France only Type 411
Quartz Halogen type bulbs:
U.K., U.S.A., Canada Type 463
Continental Type 472
Parking Light bulb (Pilot bulb):
Lucas 12 volt 6 watt No. 989
J
SECTION J17
TO CHANGE THE TAIL/STOPLAMP BULB
The lens is secured by two bright plated screws.
Release these and lift away the lens and thin gasket.
The bulb is a bayonet fitting into the bulbholder. Note
that the bulb has offset pins and will only fit the correct
way into the bulbholder on reassembly. Take care not
to crack the lens by over-tightening the screws.
Stop/tail lamp bulb:
Lucas 12 volt 6/21 watts No. 380
Indicator Repeater Light
Ignition Warning Light
H-beam Warning Light
Neutral Indicator Light
Each warning light has integral bulb unit which is not
intended to be renewed separately. If a warning light
should fail, fit a new coloured unit complete with bulb.
Access can be gained simply from beneath the console. |
To replace, detach the two spade terminals and prise
the holding clip free of the light body. When fitting the
new light, ensure the clip is fitted tó the body so that
it is a tight fit to the console and can not rattle.
Speedometer Bulb
12 volt 2:2 watts No. 643
After pulling down the PVC instrument case bottom
cover, the bulb holder is merely a push-in fit to the
bottom of the instrument and the bulb a bayonet fitting
into the holder.
Tachometer Bulb
No. 643
Bulb removal is similar to that for the speedometer.
12 volt 2:2 watts
Direction Indicator Bulb
Lucas 12 volt 21 watts
Care must be taken when refitting the lenses that
the screws are not over-tightened, resulting in splitting.
—
Electrical
SECTION J18
BRAKE STOP LIGHT SWITCHES,
NEUTRAL INDICATOR SWITCH
Front Brake Stop Switch
A sealed, non-adjustable Lucas compression switch is
incorporated in the hydraulic master cylinder. This unit
cannot be serviced though a check should be made
periodically on the cleanliness and security of the lead
terminals.
Rear Brake Stop Switch
The rear stop switch is a sealed non-adjustable
“pressure switch’ fitted in the hydraulic system at the
“T” piece in the pressure line and operated by fluid
pressure.
The unit cannot be serviced but should be periodi-
cally checked for cleanliness and security of the lead
terminals.
NEUTRAL INDICATOR SWITCH
The neutral indicator switch (new on the Mk Ill) is
fitted in the gearbox-shell beneath the rear cross-shaft
and is a sealed pressure switch, actuated by a plunger,
contacting a button on the gear shift camplate in neutral
only. The device is pre-set on assembly and should not
be readjusted. Maintenance consists of cleaning and
ensuring good electrical connections.
Current is supplied by the white wire to the green
lamp in the warning light console, via the slate-grey
wire to the connector, onward to the switch via the
green cable and thence by a red wire to earth.
The unit is energised in master switch positions
3 (IGN) and 4 (IGN & LIGHTS) only.
SECTION J19
HANDLEBAR SWITCH CLUSTERS
The switch clusters are accommodated in light alloy
castings. Whilst the switches are not sealed units, the
method of assembly renders reassembly by an owner or
dealer extremely difficult, if not impossible, and we must
recommend against attempts at dismantling.
SWITCH CLUSTER: RIGHT HAND
Light Selection Switch
Engine Stop-switch: cut-out or “kill"”’ button
Electric Starter Button
These controls are mounted in the console on the right
handelbar. The lighting switch selects the “head”
position by an upward movement; “pilot” position by a
downward movement. (Models for CANADA only are
equipped with an automatic over-riding control which
illuminates head and tail lamps whenever engine is
started.) See Section J8 for details.
The engine “stop” switch or kill-button is a 3 position
emergency switch — move to left or right to stop engine
and return (manually) to the central position before
attempting to re-start.
N.B. The engine will fire if the starter is operated with
the kill-button at "STOP" but will not continue to run!
This can be confusing, especially in the dark, and
should be remembered if the engine fails to run when
apparently firing. Always check that the stop button
has been returned to “center” before starting.
Normally use the ignition switch to stop the engine.
STARTER BUTTON
The button is pressed in bursts to operate the electric
starter. On contact the button energises the solenoid
which connects the high discharge circuit to the starter
motor.
SWITCH CLUSTER: LEFT HAND
Dip Switch
Direction Indicator
Horn Button and Flash
These controls are mounted in the console on the left
handlebar and are marked to indicate their function.
The dip switch moves to “HI” for main (high) beam,
10 “LO” for dip or low beam.
The direction indicator moves horizontally, “L” for
left or “R” for right.
The horn is operated by pressing the bottom button,
lifting the horn button operates the headlamp flash
facility.
Electrical J
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Fig. 9 Controls « Showing Handlebar switches
and 4 (IGN and LIGHTS) of the master switch;
Switch modes and circuits not in “PARK” or "OFF".
1 The starter button is fed by the white wire which
contacts the red/black wire (via the starter button) 2 The Head/Pilot lighting switch receives its current
to the solenoid. When operated this closes the via the blue/yellow wire with master-switch in
contacts on the high-discharge circuit, feeding via position 4 (IGN and LIGHTS). With the button
the heavy-duty, black cable to the starter motor. moved to the “down” position the right-hand
Keep connections clean and tight, checking switch isolates the blue/yellow feed from the blue
frequently. The white (low tension) wire to the wire to the dip switch in the left-hand cluster. In
starter button is energised in positions 3 (IGN) the “up” position the blue/yellow connects with
Electrical
the blue wire illuminating the head lamp via the
left-hand dip switch, feeding either filament as
directed by the “dipper”.
3 Stop-switch, “Cut-out” or “Kill-button”
This is normally “closed”. Move horizontally left
or right to open switch which makes contact
between the white and white/yellow wire which
feeds back to the ballast resistor, onward to the
ignition coils as white/purple in the ignition
circuit.
The circuit is broken when the button is moved
either to left or right.
4 The dip-switch is energised by the blue wire
feeding across from the right-hand light selection
switch when the button is in head position (UP).
In “Hi-beam” position the switch connects the
blue/white wire and illuminates the main (high)
filament of the head bulb. In “LO" beam position
the switch connects the blue-red, lighting the dip
or low beam filament in the bulb.
The blue wire is only live in position 4 (IGN and
LIGHTS) of the master switch with the selector
on “head” (up).
5 The direction indicator (now fitted on all
models as market requirement or at customer's
option) are fed by the light green/brown wire from
the flasher unit (Lucas type 8FL) — which in turn
receives its current via the white wire as controlled
by the master switch. The flasher is a sealed unit
requiring no maintenance.
Sideways movement to the right switches in the
green/white wire to the right-hand indicators.
Horizontal movement to the /eft connects the
green/red of the left-hand indicators.
The direction indicators are energised in positions
3 (IGN) or 4 (IGN and LIGHTS) of the master
switch.
6 The horn button is fed by the white wire and
when pressed makes contact with the purple/
black wire which connects with the horn thence
via the red wire to earth. The horn push operates
in position 3 (IGN) and 4 (IGN and LIGHTS).
J
7 The headlamp flash switch connects the white
(horn) wire with the blue and white “'main-
filament wire”. When the horn button is lifted up,
the flash facility operates only in positions 3 (IGN)
and 4 (IGN and LIGHTS).
SECTION J20
POWER TAKE-OFF SOCKET
This is located on the right side of the machine, and
provides a power source for any accessory selected by
the owner, providing the battery capacity is borne in
mind. With the battery in good condition and fully
charged it provides 12 volts at a maximum of 173 amps
for accessories, such as a radio or shaver; an auxiliary
lamp, etc. We recommend that the engine is run up as
soon as possible after the power take-off socket has
been used to restore the battery to a good state of
charge.
Caution must be exercised not to discharge the
battery completely. The same power socket is used for
charging the battery from an outside source.
When appropriate, ensure that the plug is connected
with the correct polarity. On this machine the positive —
(indicated by a red wire) — is earthed (ground).
SECTION J21
FLASHING DIRECTION INDICATORS
Bulb replacement
To replace the bulb, unfasten the screws retaining the
lens and carefully remove the lens. The bulb is then
removed by pushing inwards and rotating anti-
clockwise. When replacing the lens, ensure that the lens
body locates into the sealing gasket, before the retaining
screws are tightened.
Electrical
Checking for faulty operation
If a fault occurs in the system, the following procedure
should be adopted.
1 Check that the bulb filaments are not broken.
2 Check that all flasher circuit connections are clean
and tight,
3 Switch on ignition and check with a voltmeter that
the flasher terminal “B” is at battery voltage.
4 Connect together flasher unit terminals “B” and
“L” and operate the indicator switch. If the flasher
lamps on the respective side now light without
flashing, the flasher unit is faulty and should be
replaced with the same type of unit as the original.
If a flasher lamp stalk is replaced
On reassembly, take care not to damage the green lead
when passing through the screw thread of the lamp
shell. Final adjustment of the lamp position must be
made by tightening of the locknut and not by straining
the flasher unit.
Important
When tightening the stanchion locknut against the
body of the flasher lamp, ensure that the torque loading
figure of 35-45 Ibs./ins. is not exceeded.
Flasher Unit Lucas Type 8FL
The unit is mounted inside the headlamps, clipped into
the mounting bracket and if for any reason the bracket
is to be removed, the unit must first be withdrawn from
the clip.
SECTION J22
ALTERNATING HORN SET INTERPOL ONLY
TYPE HC3
SPECIAL NOTE: This equipment is not available in
U.S.A.
The alternating horn set comprises an alternating
horn control, special 9H horns, two 6Ra relays, a switch
and suitable connectors. Details of the individual units
are as follows:
HC 3 Alternating Horn Control
This is a transistorised multivibrator, designed to pulse
two 6Ra continuously rated relays alternately. The fre-
quency of the unit is set during manufacture and cannot
readily be altered. Hence the risk of faulty setting due to
tampering is eliminated. The unit must be mounted so
that its temperature does not exceed 50°C. Connection
polarity must be observed. The alternating horn wiring
is shown in Fig. J10.
Horns
These are type 9H and have been reset after a “running-
in” period to ensure maximum life. They must be rigidly
mounted on a solid member of the vehicle with no
loosely mounted components in the vicinity otherwise
the tone will be adversely affected. It is recommended
that the horns are mounted facing forward. The flares
should be tilted slightly downwards to allow any water
entering the horn trumpets to drain out.
Relays
Standard 6Ra continuously rated relays are used. These
should be so positioned that the cables carrying the
horn current are as short as possible.
Electrical
Technical Data
Frequency of Notes 438-495 Hz
Ratio of Notes 8:9
Sound Intensity 90 dB at 50 ft. (15:24 m)
Cycle of Signal 1—1-2 Hz
Power Consumption 60 watts
Testing Procedure
If the horns do not sound when the switch is operated.
check the voltage at the HC 3 control as follows:
1 Connect a voltmeter, red lead to the cable removed
from the +ve terminal, black lead to the cable
removed from the —ve terminal. Operate switch,
voltmeter should read the nominal voltage of the
system.
If the voltage is satisfactory at the contro! unit proceed
to check the individual horns and relays separate from
the control unit as follows:
1 Remove leads from one “R” terminal and the +ve
terminal on the control unit and join together.
Operate switch, the relay should be energised and
the associated horn should sound, if satisfactory.
2 Repeat above operation by joining together the
leads removed from the other “R” terminal and the
+ve terminal.
J
3 If both horns and relays operate normally, the fault
is in the HC 3 control unit. Replace unit.
4 If either horn does not sound, check further by
earthing leads connected to “C1” in the relay. If
horn now operates satistactorily, the fault is in the
relay. Replace unit.
Other faults, i.e. : continuously sounding horns, incor-
rect cycle of operation, etc., can be attributed to a faulty
control unit, which should be replaced.
Retuning the 9H Alternating Horns
After horns have been in use for a long period there will
probably be a deterioration in performance due to
normal wear of the contact breaker mechanism. If the
rest of the system is in order, proceed to reset the horn
contacts as follows :
Contact Adjustment on Motorcycle
1 Connect a voltmeter across the terminals of the
horn, to check the voltage as the adjustment is
being made.
2 Connect an ammeter (range 0-25A) between ter-
minals “C1” and ‘’C2”’ of the relay which supplies
the horn to be tuned.
PUSH
|
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FEED 6RA RELAY C1
о о ||.
HORN HORN
FROM BATTERY
— [C2 TT
№105
Fig. J10 Alternating horn circuit
Electrical
3 The adjustment screw should be tuned while
operating the horn until the ammeter indicates the
appropriate current consumption (see below).
Turn the screw clockwise to reduce the ammeter
reading.
NOTE:
1 Do not under any circumstances disturb the centre
core slotted screw and locknut.
2 ltis essential, when adjusting on the vehicle, that
the wiring is not overloaded. This could be caused
by attempting to sound the horn, while the con-
tacts are out of adjustment, and hence do not
open. If the horn supply is fused, the fuse should
beshorted out until adjustment has been completed.
Contacts Setting Data
High Note Horn
Setting Current Setting Voltage
12 volt 3:0 — 3:5A 13 volts
Special Low Note Horn
Setting Current Setting Voltage
12 volt 3:0 — 4:0A 13 volts
Horns should be checked for a good clear note over the
following voltage range.
12 volt 11-12-15 volts
Fig. J11 Horn in position — note cross headed adjuster screw
for horn contact breaker (arrowed)
SECTION J23
HORN ADJUSTMENT (SINGLE STANDARD
HORN)
The horn is shown in Fig. J11 with the adjustment screw
arrowed. Adjustment will take up wear on the moving
parts which, if not attended to, will cause roughness
and a loss of performance.
To adjust the horn, operate the horn button and slowly
turn the adjustment screw anti-clockwise until the horn
just fails to sound. Release the horn button and turn
the adjustment screw clockwise one notch at a time
until the original performance is regained. The amount
of adjustment may be expected to vary between a
quarter and three-quarters of a turn. Note that if
original performance is not restored, the horn must
receive attention by the electrical manufacturer.
Electrical
SECTION J24
FITTING A LUCAR CONNECTOR
Operation 1
Operation 2
Operation 3
Operation 4
Operation 5
Operation 6
Fig. JI2 Fitting instructions for Lucar connectors
Operation 1
Thread the insulating cover over the cable.
Operation 2
strip the insulation neatly from the conductor.
Operation 3
Feed the conductors through the aperture and grip
the cable firmly in the tags.
Operation 4
Splay "conductors back towards the cable and
spread flat.
Operation 5
Solder securely and neatly to the connector. Do
hot allow solder to run through the aperture.
Operation 6
Allow the joint to cool. Slide the cover over the
connectors.
It is essential that the Lucar connector is fitted in
accordance with the above instructions to ensure the
efficient operation of the associated equipment.
Electrical
SECTION J25
HOW TO MAKE UP A ONE OHM RESISTOR
The 1 ohm resistor must be accurate otherwise correct
voltage (or current) values will not be obtained.
A suitable resistor can be made from 4 yards 18 S.W.G.
(-048 in. dia.) NICHROME wire together with two
flexible leads and suitable crocodile clips, see Fig. J13.
To Calibrate
Bend the wire into two equal parts.
(a) Fix a heavy gauge flexible lead to centre bend of
the wire, and connect this lead to the positive
terminal of a 6-volt battery.
(b)
(c)
(d)
(e)
(f)
(а)
J
Connect a voltmeter across the battery terminals.
Connect an ammeter to the battery negative post.
Take a lead from the other terminal of the ammeter,
connect a crocodile clip to it, and connect to the
free ends of the wire (which should be twisted
together).
Move the clip along the wire, making contact with
both wires until the discharge reading on the
ammeter exactly equals the number of volts shown
on the voltmeter. The resistance is then 1 ohm.
Cut the wire at this point, twist the two ends
together and fix a second heavy gauge flexible
lead.
Wind the wire on to a hollow asbestos former
2 in. dia. (approximately).
Fig. J13 Construction of a one ohm resistor
Electrical
SECTION J26
ELECTRIC STARTER MOTOR
The Prestolite Starter Motor is an earth (ground) return
machine, with series connected field coils.
Operation of the starter switch on the right-hand
handlebar cluster, energises a solenoid causing its
contacts to close and transmit high-discharge current
(by-passing the main line fuse) via a heavy duty cable
to the feed terminal on the starter, which will then
operate.
MAINTENANCE/OPERATION
Ensure that the battery starter and solenoid connections
are clean and always tight. If the connections become
dirty clean the contact surfaces and smear with
petroleum jelly, replacing the protective rubber boot on
the starter terminal. No lubrication of the armature
bearings is necessary between major engine overhauls
when the unit should preferably be examined by an
expert.
Occasionally check the mounting screws in the
primary cover to ensure the motor is firmly fixed.
On cold-starting it is recommended that the initial
load is reduced by always freeing the clutch with the
kick-starter pedal and starting in neutral gear with the
clutch disengaged. An efficient, well charged battery,
is the best guarantee of reliable electric starting.
OVERHAULING STARTER MOTOR
Although the starter motor is unlikely to need attention
before a very extended mileage the following infor-
mation is given to users wishing to service their own
unit, and using the parts-packs available.
DISMANTLING
1 Remove the rubber boot and disconnect the
main-feed terminal from the starter body.
2 Unscrew the three posidrive screws from the
primary cover mounting-flange, and detach the
motor from its spigot collecting the large ‘O’-ring
J
sealing the joint. The unit will withdraw complete
with its driving pinion which is integral with the
armature shaft. An outrigger bearing previously
used at this end is no longer "bushed” since
Engine No. 325689.
Mount the motor carcase horizontally in a vice
(using protective jaws). (Note marks on both end
covers to ensure re-assembly in the original
(radial) relationship to the body.
Using a close-fitting 3” A/F ring spanner (an
open wrench will invariably slip) slacken the two
hexagon headed through-bolts. Considerable
initial torque will be needed to “crack” the tock-
ing compound on these very secure bolts. The
threads should disengage at about 2” withdrawal
length. Remove the two bolts.
Tap the end of the armature with wood to protect
the shaft and loosen the “blind'” end-cover. Stop
when the cover has moved 4”. Grasp the gear end
of the shaft to prevent it moving and ease the
cover off releasing the brush mounting plate
which is sandwiched between the cap and body.
Resistance to removal is usually due to the blind
bush in the cap. It will be necessary to withdraw
the cap firmly, maintaining good axial alignment
with the armature which has the commutator and
spring-loaded brushes at this end. The brushes
are captive in closed-ended holders.
Now tap the commutator end of the shaft (still
using the wood) and ease off the drive end-
cover. Examine the bush and oil seal and determine
need for replacement. Removal! is straightforward
as the bush is open ended and will drive out,
preferably with a shouldered drift and warming
the cover.
As the commutator withdraws from under the
brushes they will spring out of their holders (from
below). Note the method of assembly and the run
of the tail-wires. The armature will now withdraw
through the carcase and the commutator be
examined for scouring. It is unlikely that the
diameter will need truing (skimming) as the
working life is not arduous, and operation only
intermittent.
Electrical
10
11
12
Fig. 114
Collect the thrust washer and spring-shim from the
commutator end, observing the order of assembly
for re-building; spring-shim next to commutator.
See Fig: J14.
Withdraw the nylon terminal block from the
mortice in the carcase releasing the main input
brush with its tail-wire soldered to the contact.
The tail can be detached with a torch or a hot
iron if a replacement is needed.
The second brush is attached to the field windings
and crimped or swaged to its terminal. The tail
can be sheared off neatly (avoid dropping “bits”
into the windings) and the new tail soldered to the
terminal without overheating the field insulation.
Make a clean neat joint using a high melting point
solder, as the starter temperature can rise under
extreme conditions.
The bush in the blind end cap will need extracting
with a tap and bolt—a “hot-plate” will ease the
fit if available to warm the casting.
With both end caps re-bushed and a replacement
oil seal in the drive-cover, using the pre-sized
components available as a service pack (see spares
list) — the new brushes soldered to their respective
contacts and tail -wires correctly insulated, proceed
with re-assembly as follows.
gy
Electric starter motor: Exploded arrangement: Showing order of assembly
13 Lightly smear each bush with “2% molybdenum
14
15
16
disulphide grease”, also the thrust washer and
spring shim—don't over-do the quantity of grease.
Assemble brush-springs and brushes into their
respective holders, fixing the nylon terminal block
back into its mortice, position the brush plate in
situ, on the carcase and, holding back the brushes
against their springs, feed the armature through
the field windings and insert the. commutator
under the brushes—which are now “Captive”
again, and must be free in their holders.
With the thrust washer and spring shim positioned
as dismantled on the commutator end, locate the
brush plate squarely in place, line up the armature
journal in the bush and press on the cap.
Assemble the drive-end cap over the gear
(locating as marked before dismantling) insert
the two set-screws through from the blind-cap
applying a small amount of thread locking
compound, and tighten up to 8 Ib/ft. (1.10 Kgm).
Check that the armature runs freely (as permitted
by the brushes) and remember the large “O”
ring seal when installing back on the cover.
Electrical
= —
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| Routine Maintenance
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Routine Maintenance
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Routine Maintenance
SECTION K1
BREAKING IN
In the process of manufacture the best possible materials
are used and all machined parts are finished to a very
high standard but it is still necessary to allow the moving
parts to “bed in" before subjecting the engine to maxi-
mum stresses. The future performance and reliability of
the engine depends on the care and restraint exercised
during its early life.
For the first 500 miles, throttle openings should be
limited to about one-third of twist grip movement and
the cruising speed should be varied as much as possible
within this limit. Provided the engine is not allowed to
labour, the actual road speed is relatively unimportant
but throttle control should be smooth and the gearbox
used to the full to enable the engine to cope with the
prevailing conditions without undue stress. This will
also assist in “break-in” of the gearbox components. At
all times avoid violent acceleration.
After the 500 miles service the amount of throttle
opening can be increased progressively but the cruising
speed should still be varied. Full throttle should not be
used until the machine has covered at least 1,000 miles
and even then only for short bursts until 1,500 miles has
been covered, whereupon maximum performance may
be sought whenever desired.
During the "break-in" period, a certain amount of
adjustment will be necessary as the components bed in.
Attention should be given to valve rocker adjustment,
chain tension. contact breaker points gap and brakes, all
of which tend to settle down.
Do not allow the oil tank level to fall too low as
with the reduced amount in circulation the oil will
become unduly hot.
K
It is most essential to avoid glazing of the friction sur-
faces during the first few miles of use. During the first
50 miles only it is necessary to apply the disc brake
gently to mate the friction surfaces. After 50 miles of
use, the brake will be fully bedded down and ready for
maximum application.
The following information is in accordance with
the requirements of the U.S. National Highway
Traffic Safety Administration, Department of
Transportation. Part 575 Consumer Information.
Brakes should be bedded in progressively during the
first 300 miles. This is achieved by gradually increasing
brake lever pressure during the period, and braking from
progressively increasing speeds.
For guidance refer to the table below. The decelera-
tion in ft/sec? is converted to the equivalent braking
time/distance.
Stage 1 2 3
Speed of commencement
of stage (m.p.h.) 30 50 70
Speed at end of stage
(m.p.h.) 0 30 30
Deceleration (ft/s?) 12:5 12:5 12:5
Distance travelled (ft) 77 135 344
Time taken (sec) 3-5 2-3 4.7
Stage 1
A minimum of 20 stops using the front and rear brakes
together. Decelerate from 30 m.p.h. to rest using the
distance travelled or time taken to obtain the required
deceleration.
Stage 2
A minimum of 50 decelerations from 50 to 30 m.p.h.
using front and rear brakes together.
Stage 3
A minimum of 30 decelerations from 70 to 30 m.p.h.
using front and rear brakes together.
Routine Maintenance
The distance between brake applications should not
be less than 1 mile in each case. Disengage the clutch
when carrying out the procedure to ensure that the
brakes receive the full braking load. The use of the above
procedure, subject to traffic conditions will ensure that
any high spots on the brake linings are not hardened,
resulting in reduced brake efficiency. Correct burnishing
will give an approximate minimum lining contact area
of 50% which qualifies the published brake performance
figures.
Fuels
This motorcycle (Mk III Commando) is designed to
operate on fuels of at least 94 octane rating (U.K. 3-Star
or U.S.A. premium).
Always ensure that the fuel used is clean and free
from water. Do not allow foreign matter or water to
enter the fuel tank at any time.
Any engine that shows a tendency to overheat or
detonate (ping) under hard use when ignition system
and carburetors are in proper order may be cured by
switching brands of fuel or using fuel of a higher
octane rating.
FREE SERVICE CHECK
All owners of new Commando motorcycles are entitled
to a FREE SERVICE CHECK at 500 miles (800 km) or,
at latest, three months after taking delivery.
This service should preferably be undertaken by the
supplying dealer but can be undertaken by any Norton
franchised dealer.
1 Check and adjust, if necessary:
(a) Valve clearances.
(b) Contact breaker. Set gap.
(c) Ignition timing. Strobe each cylinder.
(d) Spark plugs. Check heat range and gap.
(e) Clutch operation and cable adjustment.
(f) Check fluid level for both brakes.
(g) Adjust and inspect rear chain.
(h) Wheels. Check for freedom of rotation, bearing
looseness, and spoke tension.
K
(i) Wheel alignment. Check and adjust rear wheel if
necessary.
(i) Check tire pressures.
(К) Isolastic. mountings. Check for clearance and
adjust.
2 Drain oil tank and sump, clean gauze strainer and
tank, and replace cartridge oil filter and refill with
correct grade of oil.
3 Drain and refill primary chaincase.
4 Top up gearbox.
5 Top up battery.
6 Check all electrical equipment.
7 Drain and clean carburetors.
8 Adjust and oil all control cables.
9 Grease rear brake pedal nipple.
10 Tighten all external nuts and bolts. Retorque
cylinder head and base nuts.
11 Drain and refill front forks.
12 Start the engine and check for:
(a) Oil leaks.
(b) Oil return to tank and feed to rockers.
(c) Alternator charging battery.
13 Road test the machine. !f no other rectification is
necessary; set carburetor idling adjustment. While
engine is hot, tighten exhaust lockrings fully.
Check for any signs of oil or fuel leakage.
The owner must pay for all replacement materials
but labor and time are free of charge.
It is essential for the FREE SERVICE card to be
completed, detached from inside the front cover of this
manual and handed to the dealer who has carried out
this service for return by him to the main distributor.
The warranty applies only to the first owner. There
is no transfer of warranty under any circumstances.
Routine Maintenance
SECTION K2
ROUTINE MAINTENANCE
INTRODUCTION
This section tables the maintenance periods for various
operations, co-relates these operations to other sections
of this manual and details those operations not falling
within the normal scope of the overhaul sections.
To obtain the best possible service from your Com-
mando, a regular sequence of maintenance is essential.
This is divided into simple checks by the rider at frequent
intervals, supplemeneted by dealer serivces at set
mileages. Full details of such services are given both
as follows and in the service voucher booklet which
you will receive automatically.
Regular check procedures by the owner
Weekly
Check tire pressure and wheel alignment. Use Chain-
spray to lubricate rear chain.
Every two weeks
Check battery electrolyte level.
Every 250 miles (400 Km)
Check engine oil tank level.
Every 500 miles (800 Km)
Check, adjust and spray lubricate rear chain.
Every 1,000 miles (1,600 Km)
Check primary chaincase oil level.
Oil all control cables. |
Check disc brake fluid levels, front and rear. Examine
front and rear disc brake pads for wear.
Service voucher chargeable by franchised
Norton dealer |
Mileage (Km)
3,000 (5,000)
6,000 (10,000)
9,000 (15,000)
12,000 (20,000)
15,000 (25,000)
18,000 (30,000)
21,000 (35,000)
24,000 (40,000)
Type of service
OP oD>DO>ED>
27,000 (45,000)
30,000 (50,000)
33,000 (55,000)
36,000 (60,000)
39,000 (65,000)
42,000 (70,000)
45,000 (75,000)
48,000 (80,000)
ооо
Service А
Check spark timing and adjust contact breaker points.
Clean spark plugs and set gaps.
Change primary chaincase oil.
Check clutch adjustment.
Change engine oil and cartridge filters.
Relubricate and adjust rear chain.
Check transmission (gearbox) oil level.
Grease rear brake pedal pivot.
Check front and rear Isolastic mountings for excessive
free play.
Check and adjust valve rocker clearances.
Clean and re-oil air filter element.
Service B
Includes “A” Service — plus the following:
Change transmission (gearbox) oil.
Change oil in forks.
Check and adjust camshaft chain.
Clean contact breaker points.
Lubricate contact breaker cam felt and auto advance
unit.
Clean and re-oil air filter element.
Check swinging arm bushes for wear.
Check loose or unequal spoke tension — front and rear
wheels.
Rebalance wheels where necessary.
Check front and rear wheel spindle clamp nut tightness.
Check on front and rear tire tread condition and wear
pattern. Rebalance wheels where necessary.
Examine and if necessary replace the rear wheel shock
absorbing rubbers.
Routine Maintenance
Service C
Includes “B” Service — plus the following:
Repack wheel bearings with grease.
Dismantle and clean both carburetors and check for
wear.
Adjust rear chain.
Check steering head bearings.
Check head steady and head steady mounting rubbers.
Also suspensory spring. Check and tighten all front and
rear engine mounting bolts.
Check swinging arm spindle.
Change hydraulic brake fluid, check flexible pipes,
unions, seals.
SECTION K3
MAINTENANCE TABLE
The following table lists the normal servicing operations,
the section numbers affected and the servicing intervals.
The service carried out after the motorcycle has com-
pleted its first 500 miles is deliberately omitted, being
outside the scope of normal routine maintenance and
being covered in detail elsewhere.
Section
Weekly Check tire pressures and
wheel alignment K15
Use chainspray to lubricate
rear chain K17
Every two Check battery electrolyte
weeks level K13
Every 250 Check engine oil tank level K4
miles (400 Km)
Every 500 Check, adjust and spray
miles lubricate rear chain C42
(800 Km)
Every
1.000 miles Check primary chaincase oil
(1600 Km) level K8
Oil all control cables . —
Check disc brake fluid levels
front and rear K12
Examine front and rear disc
brake pads for wear H9/10
Every
3,000 miles
(5000 Km)
Every
6,000 miles
(10000 Km)
Every
12,000 miles
(20000 Km)
Check timing and adjust contact
breaker points C39
Clean spark plugs and set gaps K14
Change primary chaincase oil K9
Check clutch adjustment C35
Change engine oil K5
Relubricate and adjust rear chain C42
Check gearbox oil level K6
Grease rear brake pedal pivot H11
Check Isolastic mounting for
free play F13/14
Check and adjust valve rocker
clearances C10
Change gearbox oil K7
Change oil in forks K11
Check and adjust camshaft chain K20
Clean contact breaker points C39
Lubricate contact breaker cam
felt and auto advance unit C39 & C40
Fit new air filter element E10
Check loose or unequal spoke
tension — front and rear wheels
Check front and rear wheel
spindle clamp and nut tightness
Check front and rear tire tread
and wear pattern.
Rebalance wheels where
necessary
Re-pack wheel bearings (including
the rear wheel sprocket bearing)
with grease H4 & H7
Dismantle and clean both
carburetors and check for wear E3/4
Check rear chain for wear
and adjust
Check steering head bearings
Check head steady and head
steady mounting rubbers
C42
Check and tighten all front mounting
and rear engine bolts
Check swinging arm spindle
Routine Maintenance
SECTION K4
ENGINE OIL TANK LEVEL
The oil tank content is indicated on a dip stick incor-
porated in the tank filler cap which is removed by
pressing and turning the cap anti-clockwise.
Access to the tank filler cap is made by releasing the
seat lock, slacken right seat knob and lift the seat on
its hinge.
Before filling fresh oil, run the engine for three to four
minutes to return excess oil from the crankcase, observ-
ing the oil circulating through the oil tank filler orifice.
Allow the oil to settle in the tank, then fill sufficient oil
of a recommended grade until the correct oil level is
shown on the dipstick. The oil level should not exceed
the “H” mark or fall below the “L” on the dipstick. It is
most important not to exceed the “H” to prevent oil
overflowing into the air filter, causing high oil consump-
tion.
OILTANK
| FILTER
9 TTL A
OILTANK LAW N
DRAIN PLUG dD Gm. |
Fig. K2 Oil tank filter and drain plug
SECTION K5
ENGINE OIL CHANGING
Release the seat lock and lift the seat on its hinges.
Take out the two right side cover top tixing bolts, and
lift the cover clear at-the bottom rubber mounting.
Drain the oil from the tank by removing the oil tank
drain plug. This should be carried out when the oil is
warm so that it flows more freely from the tank. (See
Fig. K2, item A) The crankcase drain plug (see Fig. K3,
item A) should be removed and the small amount of
oil in the sump allowed to drain off.
Clean the filter and remove and clean the adjacent
magnetic plug.
The filter can be dismantled for cleaning as shown in
Fig. KA.
Replace the oil tank and crankcase drain plug. Fill
the tank to the dip stick level with fresh oil and run the
engine at a steady speed to check the oil circulation.
The oil level should not exceed the “H” mark or fall
below the “L” on the dipstick.
y - : > —
CRANKCASE GAUZE >.
STRAINER (B)
[rrr rt
Fig. K3 Crankcase strainer and drain plug with magnetic core.
As the oil in the sump has been drained off, a moment
or two will elapse before the scavenge side of the pump —
begins to return the oil to the tank. Run the engine for
three minutes, then stop the engine and allow the oil to
settle in the tank for a further two minutes. Recheck the
oil level and top up as required. Finally, refit the side
panel (where applicable).
Fig. K4 Crankcase gauze strainer
(
Routine Maintenance
GEARBOX LEVEL PLUG(B) A
я
GEARBOX DRAIN PLUG (A)
Fig. K5 Gearbox drain and level plugs
OIL TANK FILTER
A coarse mesh metal filter is incorporated with the oil
feed pipe fixing bolt. This should be cleaned at 3,000
miles intervals — and when the oil is changed.
See Fig. K2.
CARTRIDGE TYPE OIL FILTER
(Fig. K6) |
After the first 500 mile service, this filter must be
changed at every 3,000 miles interval. The filter (shaded
area) is located behind the gearbox, between the
Isolastic mounting plates. To change, remove screw
clamp, place oil drip-tray under filter and unscrew.
Remove filter and old sealing ring. Moisten new sealing
ring with oil and install new filter hand-tight only.
Replace screw clamp.
Fig. K6
Cartridge filter
OIL SEPARATOR
See Section K10 for details. |
The oil separator (seen in Fig. K10) is fitted to the rear
left side of the airbox and requires no routine attention
other than a periodic check that the connection to the
airbox is not disengaged. Only after considerable
K
mileages have been covered need the separator be
cleaned to prevent blockage, unless the motorcycle is
continually used on very short trips where "'sludging”
may occur (especially in cold humid weather) requiring
attention to clear the pipes more often.
SECTION K6
GEARBOX OIL LEVEL
An oil level plug is fitted in the gearbox cover (see Fig.
K5).
To check level, remove plug (see Fig. K5, item B)
whereupon oil should seep gently out if level is correct.
If topping up is necessary, remove the filler cap (see
Fig. K5, item C) and replenish with correct grade of oil
until the oil begins to seep from the level plug orifice.
Replace the filler cap and the level plug.
SECTION K7
GEARBOX OIL CHANGING
The gearbox oil should be changed after a run so that
the warm oil flows more freely (see Fig. K5). Remove
the filler cap and drain plug (A) and drain the oil into a
suitable container. Replace the drain plug and fill the
gearbox through the filler cap orifice (C). Allow time
for oil to pass through the inner cover into the shell.
When the level plug is removed, oil should run from the
level plug hole (B). Allow the surplus oil to drain off and
replace the level plug and filler cap. If this method is not
followed a false level indication will be gained.
SECTION K8
PRIMARY CHAINCASE LEVEL
An oil level plug is fitted in the primary chaincase outer
cover. (See Fig. K7). To check level, remove plug (see
Fig. K7, item B) whereupon oil should seep gently out
if correct. If topping up is necessary, remove the filler
cap (see Fig. K7, item A) and replenish with correct
“grade of oil until the oil begins to seep trom the level
plug orifice. Replace the filler cap and the level plug.
Note: under no circumstances allow more than 7fl. oz.
(200 cc) of oil in primary case.
SECTION K9
PRIMARY CHAINCASE OIL CHANGING
Remove the drain plug in bottom of alternator housing
(preferably whilst machine is warm after a run) collect-
ing used oil in a suitable container placed beneath the
chaincase. Remove the filler cap, and level plug (B).
Routine Maintenance
Pour fresh oil into the filler cap orifice (A) until it begins
to run from the level plug hole. Allow the surplus to
drain off and refit the level plug and filler cap. Do not
overfill.
Fig. K7
Primary chaincase plugs
SECTION K10
SWINGING ARM PIVOT LUBRICATION
The Mk Ill swinging arm pivot is a pre-lubricated
bearing, employing felt wicks, thoroughly impregnated
with SAE 140 oil. (The factory use EP.140 with 2%
molybdenum disulphide additive.)
The wicks feed oil to the bushes which are thus
lubricated and sealed for life.
The king-pin is now rigidly cottered to its mounting
on the Mk.II. No routine maintenance is required.
SECTION K11
FRONT FORK OIL CHANGING
Under normal conditions the front forks will require no
servicing other than an occasional change of oil. Should
the oil level become low it will be indicated by excess
movement of the forks, but only after considerable
mileage.
K
Each fork leg is provided with a drain screw (see Fig.
G4) and each leg should be treated separately. Remove
the drain screw, take care not to lose the small fibre
sealing washer. Take the machine off the stand, apply
the front brake and move the forks up and down to
expel the oil. Allow a few minutes for draining and repeat
the operation with the other leg. Whilst draining the
right fork leg, the forks should be turned on full right
lock, and conversely for draining the left fork leg.
Refit the drain screws, place the machine on the
centre stand. Remove handlebars to improve accessi-
bility.
Unscrew the large filler plug at the top of each leg,
remove the speedometer and tachometer and lift the
front wheel to expose the springs.
Support the wheel with a block of wood to hold the
springs clear. Using two spanners, unscrew the filler
plugs from the damper rods.
Remove the wooden block and allow the forks to
extend fully. Pour in a measured 150 cc (5 fl. 0z.) of
oil into each leg (see Fig. K8). Because of the springs
inside the main tubes the oil will be slow to run down.
Cover the top of the tube with the hand and “pump”
the fork up and down to assist filling.
Expose the springs again and before refitting the filler
plugs to the damper rods ensure that their locknuts are
screwed down to the bottom end of the thread on the
rod. Lock the filler plugs and locknuts together then
screw in and tighten the filler plugs.
Fig. K8 Refilling fork leg with cap bolt removed
"a
Routine Maintenance
SECTION K12
DISC BRAKES: FRONT AND REAR
CHECKING HYDRAULIC BRAKE FLUID
LEVEL
The following instructions relate to both brakes which
have common hydraulic “features”.
The disc brakes are hydraulically operated. Before
taking the motorcycle on the road for the first time
ensure that the master cylinder reservoirs contain the
correct amount of fluid.
Each master cylinder contains a flexible diaphragm
seal which fits into the reservoir over the fluid. DO
NOT FILL THIS. Lift the bellows out (Fig. K9) and lay
on the upturned cap so that dirt does not adhere,
Check that the fluid is to a level of à in. from the top
of the reservoir and if necessary, correct the level using
the recommended hydraulic fluid. Where the plain wall
type of seal illustrated is fitted, collapse the diaphragm
seal as shown (Fig. K9), replace the seal closed end
downwards then refit the cap tightly. Where the seal is
of the “bellows” configuration it is unnecessary to
collapse this when fitting but the cap must still be
refitted tightly.
Hydraulic brake fluid absorbs moisture and it is most
important to keep the cap on tight and also to store the
fluid only in sealed containers. The breather hole in
the cap must be kept clear and no dirt or foreign matter
must be allowed to enter the system.
——— CAP
“~~ DIAPHRAGM
В 18 (126mm) FLUID LEVEL
Fig. K8 Checking master cylinder hydraulic fluid level
K
Hydraulic brake fluid must be handled with care as it
will attack paintwork, certain types of rubber, and
plastic.
important
When “topping up’ or refilling the master cylinder
reservoirs, use only fluid to U.S. DOT 3 specification,
such as Lockheed Series 329 Fluid for Disc Brakes.
obtainable under Norton part number 063111.
See Section H11 for disc brake maintenance and
friction pad replacement.
SECTION K13
CHECKING BATTERY ELECTROLYTE LEVEL
For access to the battery, remove the left side covet by
giving one half turn on the slotted fastener at the bottom
of the left side cover using a coin or similar object,
lifting the seat on its hinge then removing the panel up
and forwards clear of the locating pegs.
To remove the battery, pull down on the battery strap
buckle to disengage it from the battery carrier hook.
(Fig. K10). Disconnect the heavy duty starter lead and
red lead from the "+" terminal and the brown/blue lead
from the “—” terminal on the battery. Slide the vent
pipe clear. Lift out the battery, taking care not to spill
acid.
When refitting, turn the battery so that the terminals
are towards the rear of the motorcycle. If the tension on
the battery strap is insufficient, the strap can be
tightened through the buckle before the buckle is
hooked on to the battery tray. At two weeks intervals,
more frequently in hot climates, the level of the electro-
~ lyte should be checked. If necessary, add distilled water
to maintain the level indicated on the side of the
transparent battery case. Do not use tap water as this
may contain impurities harmful to the battery. Never
use a naked light when examining the cells.
If the machine is to be out of use for a lengthy period,
have the battery fully charged and give it a short
refreshing charge at 1 ampere about every two weeks.
This will suffice to keep the battery in serviceable condi-
tion. When the battery is fully charged, the specific
gravity of the electrolyte should be 1-270/1-290 at
60°F (16°C).
A he ATR ele” gh AA] A mm, EE
Routine
Fig. F10
Battery removal and electrolyte level checking
SECTION K14
SPARK PLUGS
It is most important to use the cortect grade of spark
plug, as a spark plug with a low heat factor can cause
pre-ignition and subsequent damage to the engine.
The Champion N7Y is recommended for Commando
engines.
To avoid damage to the insulator, use the plug
spanner provided in the tool kit to remove and refit the
spark plug, which should be firmly tightened to ensure a
gas tight joint.
To adjust or reset the spark plug gap, this is affected
by bending the earth, or side wire, which is ductile. Do
not attempt to bend the centre electrode. The correct
plug gap is 0-023 in. to 0-028 in. (0-59 mm to 0-72 mm).
Before refitting the plugs, see that the sealing
washers are sound, and clean the threads of the spark
plug body.
A smear of graphite grease applied to the threads of
the plug will assist in subsequent removal.
Maintenance
K
SECTION K15
TIRE PRESSURES
Two different types of tyres, Dunlop K.81 (TT100) and
Avon “GP” tyres, are used, in pairs, on Commando
models. Although these tyres differ in detail, both
require that tyre pressures be varied to cope with
changes in the loading of the motorcycle.
The following chart lists approved tyre pressures
corresponding to loads.
Ib/sq.in. Kg/sq.cm.
Commando with one 168 Ib.
(76-2 Kg) rider: Front 24 1:7
Rear 26 1:8
Commando with two 168 Ib.
(76-2 Kg) riders: Front 26 1-8
Rear 28 1-969
Commando with two 168 Ib.
(76-2 Kg) riders and pannier
luggage up to 100 Ib.
(45:36 Kg): Front 28
Rear 32
1-969
2-250
It is important to maintain correct tire pressure at
no more than 3 p.s.i. pressure variation from above
recommendation.
NOTE: Do not fit tires other than the recommended
types and sizes or the handling of the machine may be
adversely affected.
Larger section tires may also foul the mudguards
(fenders) and stays.
Always ensure that tires are fitted in accordance
with recommendation, that direction arrow points in
direction of wheel rotation (when indicated on tire).
Routine Maintenance
SECTION K16
REAR CHAIN LUBRICATION
No chain oiler is fitted to the Commando. Instead, an
aerosol can of “Chainspray” is provided in the toolkit.
To use, support the motorcycle to allow rotation of the
rear wheel. Using the extended spray tube of the can,
apply lubricant to the exposed areas of the chain,
rotating the wheel to gain access to all parts of the
chain. The Chainspray should be used at least every
week or each 500 mile interval to maintain adequate
lubrication. Always protect disc to avoid spray depos-
iting on braking surfaces.
+
ENGINE AND IGNITION SYSTEM:
ADJUSTMENTS
SECTION K17
Rocker Clearances
The rocker clearances are measured by feeler gauges
inserted between the end of the valve stem and the
rocker adjusting screw.
To gain access for adjustment, release the right side
seat knob and seat lock and raise the seat on its hinge.
Remove the fuel tank. This is attached to the frame by
two nuts at the front and two bolts and a cross strap
at the rear. The fuel pipe must be disconnected from
both taps.
Remove the spark plugs and the three rocker covers
on the cylinder head.
By means of the kick-starter pedal, rotate the engine
until the left side inlet valve is fully open. With a 0-006
in. (0:15 mm) feeler gauge, check the rocker clearance
of the right side inlet valve. If adjustment is necessary,
slacken the right side rocker adjusting screw locknut
(A) and screw the adjuster (B) out a couple of turns.
Place the feeler gauge between the adjuster and the
end of the valve stem and screw the adjuster in until it
just nips the feeler gauge. Tighten the locknut and
withdraw the gauge. It should not be tightly gripped
but should slide easily through the gap.
CROCKER \
ADJUSTER B
su
\ =
В, |
Fig. K11
Rocker adjustment
Rotate the engine until the right side inlet valve is
fully open and adjust the left side inlet valve in the same
way.
Adjust the exhaust valve rocker clearances in the
same sequence but using a 0-008 in. (0:2 mm) feeler
gauge.
For further details refer to Engine Section C10.
SECTION K18
IGNITION TIMING/CONTACT BREAKER
POINTS
See Engine Section C39 for full details of Ignition with
Static and Stroboscope Methods of adjustment.
See Engine Section C40 for details of Contact Breaker
adjustment and maintenance.
Routine Maintenance K
SECTION K19
AUTO ADVANCE UNIT
See Engine Section C38 for full details of access,
attention, etc.
SECTION K20
ENGINE CAMSHAFT CHAIN
Engine Camshaft Chain Tension
To check tension an inspection plug is provided in the
timing cover. The permissible amount of free up and
down movement at the center run of the chain must
not exceed +% in. If play is excessive, adjust as
described in the following section.
Engine Camshaft Chain Adjustment
Have available timing cover gasket 06.1092.
To adjust camshaft chain, the timing cover must be
removed by:
Disconnect oil union for rocker box oil pipe from
timing cover.
Remove cap covering contact breaker cover (two
screws).
Remove contact breaker base plate — with wires
attached (two hexagon bolts).
Remove auto advance unit — use extractor bolt
06.4298.
Remove 12 screws securing cover. Tap lightly the
joint face to break seal, withdraw the cover.
When the cover is removed oil will seep from drilling
in crankcase. Blank off drilling. (Fig. K12).
Fig. K12 Camshaft Chain [ Blanking off Oil-way.
The camshaft chain (Fig. K13) is provided with a
slipper tensioning device (A). To adjust the chain,
release the two nuts (B) securing the slipper, and move
as required. The permissible amount of free up and down
movement measured in the centre run of this chain is
+ in.
Check chain tension in more than one position.
CAMSHAFT CHAIN 0 NUTS (B)
=
OIL SEAL
GUIDE TOOL
SLIPPER
TENSIONER (A)
Fig. K13 Adjustment, Camshaft chain.
Retighten the two tensioner nuts when the correct
adjustment has been made.
а
—
Routine Maintenance
Refitting the Timing Cover
(Fig. K12) `
Use a new gasket to guard against oil leakage. Screw
oil seal guide (supplied in tool kit) into camshaft. Put
back the timing cover, firmly tighten the 12 screws.
Remove inspection cap on primary chaincase to
expose indicator plate.
Position the engine on the drive side cylinder with
the piston at top dead center on the firing stroke (both
valves closed) until the machined mark on the rotor
registers with 28° on indicator plate.
Insert the auto unit with the rivets for the bob
weights in line with the two screw holes for the contact
breaker cover — the slot in the cam face should be at
approximately 9 o'clock.
Fit the contact breaker base plate — yellow and black
lead is for the drive side cylinder.
Reset ignition timing as described in Section C39.
Ensure the oilway is unplugged before refitting cover.
When the timing cover has been refitted, pour a little
oil into the timing case, through the inspection plug
thus providing initial lubrication for the timing gear until
oil accumulates normally when running.
SECTION K21
CHAIN ADJUSTMENT
Primary Chain
The primary chain is equipped with a fully automatic
oleomatic tensioner which maintains correct tension
and requires no maintenance.
Rear Chain
See Engine/Primary Transmission C42 and Chains for
full particulars and recommendations.
K
SECTION K22
CARBURETOR ADJUSTMENT
See Carburetor Section E9 for Synchronising and
adjustments, cleaning, etc.
SECTION K23
AIR FILTER MAINTENANCE/CLEANING
See Section E10 for full details.
SECTION K24
CLUTCH ADJUSTMENT
The clutch control cable should be adjusted when
necessary to give + in. to À in. (4:76 to 6-35 mm) free
movement between the outer casing and the adjuster.
The clutch lever inside the gearbox cover should display
slight movement to confirm correct adjustment of the
rod.
See Section C35 for full particulars.
SECTION K25
STEERING HEAD BEARING
The Mk Ill steering head uses sealed non-adjustable
ball journal bearings requiring no routine maintenance.
Should a bearing display malfunction it must be
replaced.
See Section G6 for full details of Steering.
SECTION K26
DISC BRAKES - ADJUSTMENT
The hydraulic brakes require no adjustment except to
position the lever or pedal for best rider-convenience.
See Section H11 for full particulars of Disc Brake
maintenance, Pedal adjustment, Pad replacement.
Routine Maintenance
SECTION K27
ISOLASTIC ADJUSTMENT
The Mk 11! now incorporates “instant” screw thread
adjusters front and rear. See Section F12/13 and Tech.
Data for details of method and clearances.
N.B. Always remember to support the machine on a
box or similar under the frame cradle or leave it on its
wheels — not off the centrestand as this will exert stress
on the mountings.
SECTION K28
SUSPENSORY SPRING ADJUSTMENT
Particulars of this supplementary spring device now
added to the Mk Il! head-steady unit is dealt with in
Section C1, which also shows an illustration and gives
recommended limits of adjustment.
N.B. Always remember to support the machine on a
box or similar, cradle, or leave it on its wheels to avoid
stress in the mountings when adjusting. |
Avoid tampering with the adjustment without cause.
Factory settings have been checked and passed before
despatch. |
SECTION K29
DISC BRAKE MAINTENANCE
Major disc brake components used on front and rear
installations are substantially common and particulars
of the hydraulic brake apply in general to both appli-
cations.
Section H10 gives detailed instruction: and informa-
tion on construction. i
ADJUSTMENT
The brake requires no adjustment. Wear is compensated
by extra fluid passing from the master reservoir into the
slave (caliper) cylinder as the pad reduces in thickness.
K
CAUTION
Replace the friction pads when the lining material is
worn to a minimum thickness of 1% in. (1:5 mm).
Should the brake become “spongy” in operation or
have excessive lever travel, the brake hydraulic system
should be examined and rectified by a Norton dealer.
SECTION K30
TRACING TROUBLE
Engine fails to start, or is difficult to start, may be due
to:
ignition not switched on.
Electrical short.
Water on high-tension coils or contact breaker.
Moisture on spark plugs.
Oiled up, or fouled, spark plugs.
Throttle opening too large.
Carburetor pilot jet choked.
Air lever in open position or bad air leak at carburetor
joints.
Lack of fuel because of insufficient flooding.
Lack of fuel because pipe, or tap, obstructed.
Excessive flooding of carburetor (with hot engine only).
Valve not seating properly.
Contacts points dirty.
Incorrect contact point gap.
Kill switch at “off” position.
Electric starter disconnected (use kickstart).
Solenoid disconnected or defective (use kickstart).
Engine misfire may be due to:
Defective or oiled spark plugs.
Defective engine-to-frame earth wire.
Defective spark plug wire.
Incorrect contact point gap.
Contact breaker points loose.
Oil on contact breaker points.
Rocker adjustment incorrect.
Water in carburetor.
Air filter clogged.
Broken wire shorting on frame.
Partially obstructed petrol supply.
Disconnected carburetor balance pipe.
Routine Maintenance
Loss of power may be due to:
Faulty spark plugs.
Lack of oil in tank.
No rocker clearance, or too much clearance.
Weak or broken valve spring.
Sticky valve system.
Valve not seating properly.
Brakes adjusted too closely.
Badly fitting or broken piston rings.
Punctured carburetor float.
Engine carbonised.
Retarded ignition.
Clogged air filter.
Unsuitable fuel.
Engine overheats may be due to:
Lack of proper lubrication. (Quality or quantity of oil.)
Faulty spark plugs.
Air control to carburetor out of order.
Punctured carburetor float.
Engine carbonised.
Weak valve springs.
Pitted valve seats.
Worn piston rings.
Ignition setting incorrect.
Automatic timing control faulty.
Low octane fuel.
Engine stops suddenly may be due to:
Water on hiyh tension coils or spark plugs.
Loose coil ciinnections.
No petrol in tank, or choked petrol supply. Vent hole
in petrol tank filler cap choked.
Choked main jet.
Water in carburetor float chamber.
Oiled up or fouled spark plugs.
Electric starter does not function may be due to:
Badly discharged battery.
Bad electrical connections.
Excessive engine oil viscosity.
Excessive petrol consumption
Excessive petrol consumption may be due to:
Leaks in the petrol feed system.
(Damaged fibre washers, loose union nuts on
piping, defective float needle action).
Incorrect ignition settings. (Ignition not advanced
sufficiently).
Steering unsatisfactory
Wheels out of alignment.
Front and/or rear tire tread not correctly manipulated
to run true with wheel (causes handlebar oscillation
at low road speed).
Tire treads worn flat.
Excessive luggage mounted too high or too far back.
Wheels out of balance.
Loose front or rear wheel spindle or wheel bearings.
Slackness of steering head bearings and swing arm
spindle bushes.
Unequal suspension action caused by incorrect
quantity or grade of oil in fork or dissimilar rear
suspension unit settings.
Loose spokes — front and rear wheels.
Loose engine bolts. |
Loose or broken engine head steady.
Isolastic mounting clearances in excess of 0-010 in.
(0-254 mm).
Disc brake “spongy”
Air in brake hydraulic system.
Brake requires bleeding.
Abnormal tire wear
Abnormal tire wear may be due to:
Incorrect tire pressure.
Wheels not in alignment.
Harsh driving methods. (Misuse of acceleration and
braking).
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