Royal Enfield SUPER METEOR 1956 Workshop Maintenance Manual

WORKSHOP
MAINTENANCE MANUAL
FOR THE
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Enfield
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CONSTELLATION 1958 on
SUPER METEOR 1956 on
MAN11
Contents
SECTION A4
ENGINE DATA (SUPER METEOR)
SECTION A11
ENGINE DATA (CONSTELLATION)
SECTION B4
ENGINE SPECIFICATION (SUPER METEOR)
SECTION B11
ENGINE SPECIFICATION (CONSTELLATION)
OPERATIONS WITH ENGINE IN FRAME (SUPER METEOR)
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SECTION C4
OPERATIONS WITH ENGINE IN FRAME (CONSTELLATION)
SECTION D10
OPERATIONS WITH ENGINE REMOVED (ALL MODELS)
SECTION E4
GEARBOX AND CLUTCH (S/METEOR + 1961 CONSTELLATION)
SECTION E7
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SECTION C11
SECTION G2j
SECTION H5
BATTERY
HEAD AND TAIL LAMPS
FRAME
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SECTION J1
DISTRIBUTOR/CHARGING
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SECTION G5d
GENERATOR/RECTIFIER CHARGING SET
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SECTION G4a
K2F MAGNETO
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SECTION G2j
SR2 MAGNETO
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SECTION G1f
MONOBLOC CARBURETTER
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SECTION G1d
T.T. CARBURETTER
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SECTION F4
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SECTION F3
GEARBOX AND CLUTCH (1958-60 CONSTELLATION)
FRONT FORK
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SECTION K6
FRONT WHEEL (DUAL BRAKE)
SECTION L9
REAR WHEEL (QUICKLY DETACHABLE)
SECTION M6
SPECIAL TOOLS
SECTION P1
AIRFLOW FAIRING
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SECTIONAL VIEW OF TYPICAL TWIN CYLINDER ENGINE (EARLY TYPE)
SECTION A4
Technical Data
Super Meteor Engine
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Cubic Capacity ... ...... ... ...... ... ......... 692 c.c.
Stroke ................. ... ................... ........ 90 m.m.
Bore ......... ... ...... ... .. Nominal
70 m.m.
Actual 69.874 m.m./2.751 in.
(Rebore to .020 in. when wear exceeds .0065 in.
and again to .040 in. after further .0065 in. wear).
Camshaft Bearing External Diameter .9095/.9085 in.
Camshaft Bearing Internal Diameter .7505/.7495 in.
(Bored in position in crankcase)
Cam Lift ............. ... ......... ..... ...
.3125 in.
Valve Lift (approx.). ........
.3125 in.
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Compression Ratio ... ... ...
7.1/4 to 1
Piston DiameterBottom of SkirtFore and Aft.
69.811 m.m.
Top Lands
69.40/69.35 m.m.
Skirt is tapered and oval-turned.
Piston Rings
Width-Plain Rings ................ ... .0625/.0635 in.
Scraper Ring ......................... ... .1550/.1560 in.
Valve Spring Free Length
Inner
2.1/32 (early)
1.1/2 in. (late)
Outer
2.3/32 (early) 1.11/16 in. (late)
(Renew when reduced by 3/16 in. early or 1/16 in. late)
Valve Timing with .012 in. clearance-Exhaust Opens
...
... 75° before B.D.C.
Exhaust Closes
... 35° after T.D.C.
Inlet Opens ...
...
... 30° before T.D.C.
Inlet Closes ...
...
... 60° after B.D.C.
Timing Sprocket ............. ..... ... ...... 12 Teeth
Camshaft Sprocket ......... ..... ... ...... 24 Teeth
Magneto Sprocket ........... ..... ......... 19 Teeth
Timing Chain-Type
Single No. 110038 endless
Length ... ..... ... ... 66 pitches
Width ... ..... ...
.225 in.
Pitch
... ..... ...
.375 in.
Roller ... ..... ...
.250 in.
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Radial Thickness .................. 2.883/3.085 m.m.
Gap when in unworn Cylinder .011 / .015 in.
Clearance in grooves
.001/ .003 in.
Renew Piston Rings when gap exceeds 1/16 in.
Various oversize Pistons and Rings available.
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Tappet Stem Diameter .......... ... .3743/.3740 in.
Tappet Guide Internal Diameter .3755/.3745 in.
Tappet Guide External Diameter 1.0125/1.0130 in.
Tappet Guide Hole in Crankcase Dia 1.011/1.010 in.
Tappet Clearance with cold engine:
Inlet .............. ... ..... ... ...... ... ............. Nil
Exhaust ................. ... ....................... Nil
Engine Sprocket (33t Early)
29 Teeth
Clutch Sprocket ........... ......... ... ...
56 Teeth
Final Drive Sprocket (Solo) ... ...... ... 18 Teeth
Final Drive Sprocket (Sidecar) ..... .. 16 Teeth
Primary Chain Type
Duplex No. 114038 endless
Length
(94 pitches early) 92 pitches
Width .......... ......... ... ...... ...
.628 in.
Pitch ............ ......... ... ...... .…
375 in.
Roller .......... ......... ... ...... ... ......... .250 in.
Feed Oil Pump-Speed .. ....... ... . 1/6 Engine Speed
Piston Diameter .24975/.24950 in.
Stroke ... ...
.5 in.
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Inlet Valve Stem Diameter .... ... .3430/.3425 in.
Exhaust Valve Stem Diameter ... .3410/.3405 in.
Valve Guide Internal Diameter
.3437/.3447 in.
Valve Guide External Diameter .6275/.6270 in.
Valve Guide Hole in Cylinder Head Dia. .625/.626 in.
Magneto Speed ... ......... ..... Half Engine Speed
Points
... ......... .....
015 in.
Timing Advanced 3/8 in.-7/16 in. before T.D.C.
Timing Retarded
1/32 in. before T.D.C.
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Rocker Inside Diameter ... ...... ... .5627/.5622 in.
Rocker Bearing Inside Diameter .5622/.5617 in.
Rocker Spindle Diameter ...... ... .5617/.5615 in.
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Driving Side Main Ball Bearing
Type ............ ... ..... ... ...... ... ....... S.K.F.6209
Outside Diameter ... ...... ... ......... 85 m.m.
Inside Diameter
... ...... ... ......... 45 m.m.
Width ........... ... ..... ... ...... ... ......... 19 m.m.
Timing Side Main Roller BearingType ............ ... ..... ... ...... ... ...... S.K.F. N209
Outside Diameter .. ... ...... ... ......... 85 m.m.
Inside Diameter .... ... ...... ... ......... 45 m.m.
Width ........... ... ..... ... ...... ... ......... 19 m.m.
Magneto Chain-Type Duplex No. 114500 endless
Length ........ ... ... 44 pitches
Width ... ..... ... ... 8.64 m.m.
Pitch ... ..... ... ... 8 m.m.
Roller ... ..... ... ... 5 m.m.
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Piston Boss Internal Diameter ....... .7499/.7501 in.
Gudgeon Pin Diameter
.7499/.7501 in.
ConRod Small End Internal Diameter .7507/.7505 in.
Big End Internal Diameter ........... 2.0190/2.0185 in.
Bearing Shell Internal Diameter 1.8760/1.8755in.
Crank Pin Diameter ............... ... 1.8750/1.8745in.
Return Oil Pump-Speed
.. 1/6 Engine Speed.
Piston Diameter .375.3755 in.
Stroke ... ...
.5 in.
Spark Plug:
Early type
(short reach) Champion L5 or L11S
Late type
(long reach) Champion N3 or NA10
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1959 CONSTELLATION
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SECTION A11
Technical Data
Constellation Engine
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Cubic Capacity ... ...... ... ...... ... ......... 692 c.c.
Stroke ................. ... ................... ........ 90 m.m.
Bore ......... ... ...... ... .. Nominal
70 m.m.
Actual 69.877 m.m./2.752 in.
(Rebore to .020 in. when wear exceeds .0065 in.
and again to .040 in. after further .0065 in. wear).
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Compression Ratio ... ... ...
8 to 1
Piston DiameterBottom of SkirtFore and Aft.
69.811 m.m.
Top Lands (later type)
69.31/69.26 m.m.
Top Lands (early type) 69.40/69.35 m.m.
Skirt is tapered and oval-turned.
Piston Rings
Width-Plain Rings ................ ... .0625/.0635 in.
Scraper Ring ......................... ... .1550/.1560 in.
Camshaft Bearing External Diameter .9095/.9085 in.
Camshaft Bearing Internal Diameter .7505/.7495 in.
(Bored in position in crankcase)
Cam Lift Exhaust ... ......... ..... ...
.3280 in.
Inlet..... ......... ........
.3440 in.
Valve Lift Exhaust (approx.). ...
.3280 in.
Inlet (approx.) ......
.3440 in.
Timing Sprocket ............. ..... ... ...... 12 Teeth
Camshaft Sprocket ......... ..... ... ...... 24 Teeth
Magneto Sprocket ........... ..... ......... 19 Teeth
Timing Chain-Type
Single No. 110038 endless
Length ... ..... ... ... 66 pitches
Width ... ..... ...
.225 in.
Pitch
... ..... ...
.375 in.
Roller ... ..... ...
.250 in.
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Radial Thickness .................. 2.883/3.085 m.m.
Gap when in unworn Cylinder .011 / .015 in.
Clearance in grooves
.001/ .003 in.
Renew Piston Rings when gap exceeds 1/16 in.
Various oversize Pistons and Rings available.
Valve Spring Free Length
Inner ............ ... ...... ...
1.1/2 in.
Outer ..................................... 1.11/16 in.
(Renew when reduced by 1/16 in.)
Valve Timing with .012 in. clearance-Exhaust Opens
...
... 83° before B.D.C.
Exhaust Closes
... 35° after T.D.C.
Inlet Opens ...
...
... 24° before T.D.C.
Inlet Closes ...
...
... 73° after B.D.C.
Engine Sprocket ........... ... ...... ... ...
29 Teeth
Clutch Sprocket ........... ......... ... ...
56 Teeth
Final Drive Sprocket (Solo) ... ...... ... 20 Teeth
Primary Chain Type
Duplex No. 114038 endless
Length ......... ......... ... ...... ... ..
92 pitches
Width .......... ......... ... ...... ...
.628 in.
Pitch ............ ......... ... ...... .…
375 in.
Roller .......... ......... ... ...... ... ......... .250 in.
Feed Oil Pump-Speed .. ....... ... . 1/6 Engine Speed
Piston Diameter .24975/.24950 in.
Stroke ... ...
.5 in.
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Tappet Stem Diameter ........... ... .3743/.3740 in.
Tappet Guide Internal Diameter .3755/.3745 in.
Tappet Guide External Diameter 1.0125/1.0130 in.
Tappet Guide Hole in Crankcase Dia 1.011/1.010 in.
Tappet Clearance with cold engine:
Inlet .............. ... ..... ... ...... ... ............. Nil
Exhaust ................. ... ....................... Nil
For continuous high speed running set
Exhaust tappet to .005 in. clearance
Magneto Speed ... ......... ..... Half Engine Speed
Points
... ......... .....
015 in.
Timing Advanced 3/8 in.-7/16 in. before T.D.C.
Timing Retarded
1/32 in. before T.D.C.
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Rocker Inside Diameter ... ...... ... .5627/.5622 in.
Rocker Bearing Inside Diameter .5622/.5617 in.
Rocker Spindle Diameter ...... ... .5617/.5615 in.
Inlet Valve Stem Diameter .... ... .3430/.3425 in.
Exhaust Valve Stem Diameter ... .3410/.3405 in.
Valve Guide Internal Diameter
.3437/.3447 in.
Valve Guide External Diameter .6275/.6270 in.
Valve Guide Hole in Cylinder Head Dia. .625/.626 in.
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Driving Side Main Ball Bearing
Type ............ ... ..... ... ...... ... ....... S.K.F.6209
Outside Diameter ... ...... ... ......... 85 m.m.
Inside Diameter
... ...... ... ......... 45 m.m.
Width ........... ... ..... ... ...... ... ......... 19 m.m.
Timing Side Main Roller BearingType ............ ... ..... ... ...... ... ...... S.K.F. N209
Outside Diameter .. ... ...... ... ......... 85 m.m.
Inside Diameter .... ... ...... ... ......... 45 m.m.
Width ........... ... ..... ... ...... ... ......... 19 m.m.
Magneto Chain-Type Duplex No. 114500 endless
Length ........ ... ... 44 pitches
Width ... ..... ... ... 8.64 m.m.
Pitch ... ..... ... ... 8 m.m.
Roller ... ..... ... ... 5 m.m.
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Piston Boss Internal Diameter ....... .7499/.7501 in.
Gudgeon Pin Diameter
.7499/.7501 in.
ConRod Small End Internal Diameter .7507/.7505 in.
Big End Internal Diameter ........... 2.0190/2.0185 in.
Bearing Shell Internal Diameter 1.8760/1.8755in.
Crank Pin Diameter ............... ... 1.8750/1.8745in.
Return Oil Pump-Speed
.. 1/6 Engine Speed.
Piston Diameter .375.3755 in.
Stroke ... ...
.5 in.
Spark Plug:
Engine numbers SMSA 6751 - 6795
(short reach) Champion L5 or L11S
Engine numbers SMSA 6796 onwards
(long reach) Champion N3 or NA10
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SECTION B4
Engine Specification
" Super Meteor "
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1. Engine
The engine is an even-firing vertical twin
cylinder, having separate cylinders and heads
and fully enclosed pressure-fed overhead valve
gear. It has dry sump lubrication with the oil
tank integral with the crankcase and a massive
one piece high-strength cast iron crankshaft.
6. Crankcase
The combined crankcase and oil tank is
die-cast from light alloy in two halves, being
split vertically.
7. Crankshaft and Flywheel
The crankshaft is cast in one piece, integral
with the massive central flywheel, from high
quality meehanite cast iron. The total weight is
26lbs. and it is carefully balanced.
The main journals are ground and the big end
journals are ground and hand-lapped.
8. Main Bearings
Heavy duty bearings are provided for the
crankshaft, the driving side being ball and the
timing side roller.
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2. Cylinder Heads
The cylinder heads are die-cast from light
aluminium alloy with ample finning to ensure
adequate cooling. The exhaust pipe inserts are
cast in and the valve inserts are of austenitic
iron and are shrunk in so that they are
replaceable. Steel wire thread inserts which are
easily renewable are provided for the sparking
plugs to prevent damage to the threads in the
heads. The large capacity induction ports are
streamlined and blended to the valve seatings.
bolted to the connecting rods by means of high
tensile socket screws, secured by cotter pins.
10. Valves
The inlet valves are machined from
stampings of special Silicon-Chrome Valve
Steel and the exhaust valves are of austenitic
steel.
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11. Valve Gear
The valves are operated from the camshafts
by means of large flat based guided tappets,
tubular alloy push rods and overhead rockers.
Two compression springs are fitted to each
valve.
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5. Connecting Rods
The connecting rods are produced from
stampings of Hiduminium RR56 light alloy. The
little end bearings are of alloy direct on to the
gudgeon pin. In case of wear after long service
the little end can be bored out and fitted with a
bush, but this is rarely necessary.
The big end bearings are of alloy direct to the
crankshaft. The detachable bearing caps are
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4. Pistons
The high compression pistons are of low
expansion aluminium alloy, heat treated and
form-turned oval and having split skirts. The
compression ratio is 7¼ to 1. There are three
piston rings, the top two of which are
compression rings. Both are taper ground and
the top one is chromium plated. The third ring is
for oil control and is slotted.
9. Camshafts
The camshafts are machined from drop
forged steel stampings with the cams and
bearings hardened and ground. The cam profiles
are produced with silencing ramps to ensure
quiet running.
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3. Cylinders
The separate cast iron cylinders have a
nominal bore of 70 m.m., the stroke being 90
m.m. The cubic capacity of the engine is 692
c.c. The cylinder heads are located on the
cylinders by hollow dowels.
12. Timing Drive
The camshafts are located in the crankcase,
running in bronze bushes. They are driven by a
common, endless chain from the timing
sprocket on the crankshaft and the tightness of
the chain can be adjusted by means of the chain
tensioner in the timing chest.
Section B4 Page 1
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16. Lubrication System
Lubrication is by the Royal Enfield Dry
Sump system which is entirely automatic and
positive in action. The oil tank is integral with
the crankcase, ensuring the full rate of
circulation immediately the engine is started and
rapid heating of the oil in cold weather.
There are two positively driven piston type
oil pumps running at engine speed, one at the
rear of the timing cover for pumping oil to the
bearings under pressure and the other at the
front for returning the oil from the crankcase to
the tank. The return pump has a capacity
approximately double that of the feed pump
which ensures that oil does not accumulate in
the crankcase.
The oil from the big ends drains into the
bottom of the crankcase and is prevented by a
baffle from being drawn up by the flywheel.
The oil from the rocker bearings is squirted
through a small hole in the rocker on to the top
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Section B4 Page 2
15. Air Filter
The air filter is a Vokes Micro-Vee felt and
gauze dry filter, 5 in. diameter and housed in a
compartment of the toolbox.
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The magneto is driven by a separate endless
chain from the rear camshaft sprocket in the
timing chest. The tension of this chain is
adjusted by moving the magneto fixing bolts in
their slotted holes.
13. Ignition and Lighting System. (See
Section G)
Separate systems are provided for ignition
and lighting. The former is by the latest type of
Lucas brushless Magneto with rotating magnet
and stationary contact breaker. The magneto
runs at half engine speed and has a built-in
distributor and double cam.
Lighting current is supplied by the battery
which is charged through a rectifier from an
alternator consisting of a rotating magnet
mounted on the crankshaft and running in a
six-coil stator in the primary chaincase.
14. Carburettor. (See Section F2)
Amal Monobloc Type 376/41 Bore 1 1/16in.
Main Jet
... ... 240
Needle Jet
... ... Standard
Pilot Jet
... ... 30 c.c.
Throttle Valve ...... No. 3½
Needle Position ...... No. 3
Pilot Outlet
... ... .025 in.
The breather is located on the driving side of
the crankcase and consists of a small housing
attached to the crankcase by three screws and
having a short rubber tube with flattened end,
which acts as a non-return valve.
On some models the housing contains two
pen-steel discs covering two holes drilled in the
crankcase. Accurate seating of the discs is
ensured by a pen-steel plate held between the
breather body and the crankcase.
18. Gearbox
The gearbox is bolted on to the back of the
crankcase and has four speeds, which are foot
controlled, and a patented neutral finder. All
gears are in constant mesh, changes being
effected by robust dog clutches. (See Section
E).
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end of the pushrod. It flows down the push rod
into the cam tunnel where it lubricates the cams
and tappets and thence into the timing chest,
lubricating the timing chains. There are small
holes from the cam tunnels through the cylinder
walls for the purpose of lubricating the skirts of
the pistons.
Both pumps are double acting, one side of
the feed pump supplying the big ends only and
the other side the rockers and valve gear. In a
similar manner one side of the return pump
pumps the big end oil back to the tank from the
crankcase and the other side the valve gear oil
back to the tank from the timing chest.
A spring loaded relief valve controls the
pressure of the oil to the valve rocker gear
which is through external pipes.
A gauze strainer is provided for the feed oil
leaving the tank and there is a large capacity felt
filter in the feed to the big ends. An aluminium
cylinder is fitted over the fixing stud inside the
filter element to reduce the volume of oil
required to fill the filter after it has been
dismantled for cleaning and to ensure the rapid
flow of oil to the big ends.
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The standard gear ratios are as follows :...... Solo Sidecar
Bottom Gear
...... 12.05 13.55
Second Gear ........ ...... 7.87
8.85
Third Gear ........... ...... 5.63
6.34
Top Gear .............. ...... 4.33
4.88
19. Clutch
The clutch has six pressure plates and five
friction plates, including the sprocket which is
lined on both sides with friction material. The
other friction plates have Klinger inserts which
give smooth operation and freedom from
slipping in the presence of oil.
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17. Breather
The efficient operation of the breather is of
paramount importance to the performance of the
engine as it acts as a non-return valve between
the crankcase and the outside atmosphere,
causing a partial vacuum in the crankcase and
rocker boxes which prevents the passage of oil
into the cylinders and consequent smoking and
oiling of the plugs.
Section B4 Page 3
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The ports in the housing are connected as follows
W - delivery to rocker gear.
Y - suction from oil tank.
X - delivery to big ends.
Z - suction from oil tank.
Position 2. The plunger A is being pushed into the
cylinder hole in the disc C. The port T in the disc
now registers with the delivery port X in the housing,
so that oil is forced out of the cylinder to the big
ends. At the same time the suction port Z in the
housing is uncovered and oil is drawn into the
housing below the disc from the oil tank.
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Position 1. The plunger A is being drawn out of
the cylinder hole in the disc C by the action of the peg
B on the shaft D. The port T in the disc C registers
with the suction port Y in the housing, so that oil is
drawn into the cylinder from the oil tank. At the same
time the delivery port W in the housing is uncovered
and oil below the disc in the housing is forced through
W to the rocker gear.
The ports in the housing are connected as follows :
W' - delivery to oil tank.
Y' - suction from crankcase.
X' - delivery to oil tank.
Z' - suction from timing chest.
Position 1. The plunger A' is being drawn out of
the cylinder hole in the disc C' by the action of the
peg B' on the shaft D'. The port T' in the disc C'
registers with the suction port Y' in the housing, so
that oil is drawn into the cylinder from the crankcase
sump. At the same time the delivery port W' in the
housing is uncovered and oil below the disc in the
housing is forced through W' back to the oil tank.
Section B4 Page 4
Position 2. The plunger A' is being pushed into the
cylinder hole in the disc C'. The port T' in the disc
now registers with the delivery port X' in the housing,
so that oil is forced out of the cylinder back to the oil
tank. At the same time the suction port Z' in the
housing is uncovered and oil is drawn into the
housing below the disc from the timing chest.
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1956 SUPER METEOR
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SECTION B11
Engine Specification
“Constellation”
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1. Engine
The engine is an even-firing vertical twin
cylinder, having separate cylinders and heads
and fully enclosed pressure-fed overhead valve
gear. It has dry sump lubrication with the oil
tank integral with the crankcase and a massive
one piece high-strength cast iron crankshaft.
6. Crankcase
The combined crankcase and oil tank are
die-cast from light alloy in two halves, being
split vertically.
7. Crankshaft and Flywheel
The crankshaft is cast in one piece, integral
with the massive central flywheel, from high
quality spheroidal graphitic cast iron. The total
weight is 24 lbs. and except in some earlier
engines the crankshafts are dynamically
balanced.
The main journals are ground and the big end
journals are ground and hand-lapped. The main
journal on the drive side of the later type
crankshaft is drilled through its centre for the
situation and operation of the crankcase breather.
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2. Cylinder Heads
The cylinder heads are die-cast from light
aluminium alloy with ample finning to ensure
adequate cooling. The exhaust pipe inserts are
cast in and the valve inserts are of austenitic iron
and are shrunk in so that they are replaceable.
Steel wire thread inserts which are easily
renewable are provided for the sparking plugs to
prevent damage to the threads in the heads. The
large capacity induction ports are stream-lined
and blended to the valve seatings.
The big end bearings consist of
white-metalled steel liners which are renewable.
The detachable bearing caps are bolted to the
connecting rods by means of high tensile socket
screws, secured by cotter pins.
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3. Cylinders
The cylinders are separate and of cast iron,
with internal tunnels enclosing the push rods.
The cylinder heads are located by spigots on the
cylinder barrels.
The cylinder heads are located on the
cylinders by hollow dowels.
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9. Camshafts
The camshafts are machined from
drop-forged steel stampings with the cams and
bearings hardened and ground. The cam profiles
are produced to give racing performance and, in
order to obtain the maximum efficiency, the
usual silencing ramps are omitted.
The camshafts are located in the crankcase
and run in bronze bushes. The bushes on the
near side are pressed into detachable housings
which are bolted to the driving side crankcase.
This enables the camshafts to be changed, if so
desired for tuning purposes, without the
necessity of dismantling the crankcases.
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5. Connecting -Rods
The connecting rods are produced from
stampings of Hiduminium RR56 light alloy. The
little end bearings are of alloy direct on to the
gudgeon pin. In case of wear after long service
the little end can be bored out and fitted with a
bush, but this is rarely necessary.
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4. Pistons
The pistons are of low expansion aluminium
alloy, heat-treated and form-turned oval. The
compression ratio is 8 to 1.
Early models have three piston rings, the top
two being compression rings, the bottom one a
single slotted scraper. Later models have pistons
of lighter weight than earlier types, and whilst
retaining similar compression rings, the bottom
piston ring groove contains 2 separate oil
control rings (see Fig. 7, section C). All
compression rings are taper ground, the top one
being chromium plated.
8. Main Bearings
Heavy duty bearings are provided for the
crankshaft, the driving side being ball and the
timing side roller.
10. Valves
The inlet valves are machined from
stampings of special Silicon-Chrome Valve
Steel and the exhaust valves are of High
Nickel-Chromium Tungsten valve Steel with
the stems stellite-faced.
Section B11 Page 1
tachometer if this is required. This drive can be
fixed to an aperture provided in the timing
cover, which is otherwise covered by a small
plate.
13. Ignition and Lighting System (See Section
G)
The ignition is supplied from a Lucas K2F
magneto and the lighting and other electrical
circuits from a 6-volt battery which is charged
through a rectifier from a Lucas alternator.
The alternator is housed in the primary
chaincase, the permanent magnet rotor being
mounted on the end of the crankshaft and the six
coil stator fixed to the back of the chaincase.
The magneto is chain-driven from the inlet
camshaft at half engine speed and the timing is
hand controlled from a lever on the handlebar.
14. Single Carburettor (see Section F)
The carburettor is an Amal Type Tl0.TT9,
with a bore of 1.3/16 inches.
For very high speeds it is essential to have an
independent float chamber flexibly mounted as
near the centre-line of the machine as possible.
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11. Valve Gear
The valves are operated from the camshaft by
means of large, flat-based, guided tappets,
tubular alloy push rods with induction hardened
steel ends and overhead rockers. Two
compression springs are fitted to each valve
secured by Bullock Type split collets locking in
Timinium collars. The springs are specially
designed to give a variable rate on compression.
12. Timing Drive
The camshafts are located in the crankcase,
running in bronze bushes. They are driven by a
common endless chain from the timing sprocket
on the crankshaft and the tightness of the chain
can be adjusted by means of the chain tensioner
in the timing chest.
The magneto is driven by a separate endless
chain from the rear camshaft sprocket in the
timing chest. The tension of this chain is
adjusted by moving the magneto fixing bolts in
their slotted holes.
A special slotted bolt securing the front
camshaft sprocket provides a drive to a
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There is, however, a tendency to flood, and for
normal use a conventional float chamber fixed
to the carburetter is more satisfactory.
Main Jet ...
... ... 480
Needle Jet ...
... ... 109
Throttle Valve
... ... No. 5
Needle Clip in third groove from top.
Twin Carburetters (see Section F)
Both carburetters are identical in all respects
but for the float chamber arrangement, which is
as follows
Carburettor type 376/242 supplies the
left-hand cylinder, and has an integral float
chamber which also controls the fuel supply via
a connecting pipe to the right hand instrument
type 376/243. This does not have a float
chamber in unit with it.
Main Jet ........................ ... ... 320
Needle Jet ..................... ... ... 106
Throttle Valve
.......... ... ... 376/4
Pilot Jet ......................... ... ... 25 c.c.
Needle Position .......... ... ... 3
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15. Air Filter
Provision is made for housing a 5 in.
diameter Vokes Micre-Vee felt and gauze dry
filter in a compartment of the toolbox, but the
use of this may reduce the maximum speed
slightly.
Owing to the positions of the twin
carburettors in relation to the toolbox, it is not
possible to attach air filters in this instance.
tunnel into the timing chest through which
surplus oil from the inlet rockers passes.
The exhaust cam tunnel, however, has no
holes but is kept full of oil to ensure adequate
lubrication of the exhaust cams and prevent
wear. The oil level is maintained to a height in
the groove in the tappet guide where a hole is
drilled into the timing chest, through which
surplus oil from the exhaust rockers passes.
Both pumps are double acting, one side of
the feed pump supplying the big ends only and
the other side the rockers and valve gear. In a
similar manner one side of the return pump
pumps the big end oil back to the tank from the
crankcase and the other side the valve gear oil
back to the tank from the timing chest.
A spring loaded relief valve controls the
pressure of the oil to the valve rocker gear
which is through external pipes.
A gauze strainer is provided for the feed oil
leaving the tank and there is a large capacity felt
filter in the feed to the big ends. An aluminium
cylinder is fitted over the fixing stud inside the
filter element to reduce the volume of oil
required to fill the filter after it has been
dismantled for cleaning and to ensure the rapid
flow of oil to the big ends.
A small circular magnet is also fitted over
the fixing stud inside the oil filter for the
purpose of collecting any ferrous particles
which may be suspended in the oil.
17. Breather
The efficient operation of the breather is of
paramount importance to the performance of the
engine. It acts as a non-return valve between the
crankcase and the outside atmosphere, causing a
partial vacuum in the crankcase and rocker
boxes which prevents the passage of oil into the
cylinders and consequent smoking and oiling of
the plugs.
The breather is located on the driving side of
the crankcase and consists of a small housing
attached to the crankcase by three screws. This
housing contains two pen-steel (or paper) discs
covering two holes drilled into the crankcase.
Accurate seating of the discs is ensured by a
pen-steel plate held between the breather body
and the crankcase.
The Neoprene pipe, found on early models,
which breathes directly into the atmosphere
from the breather housing, has been replaced on
later models by a metal pipe running from the
breather housing to the top of the oil tank.
In addition a breather, in the form of a pensteel disc, is situated in a recess in the head of
the special bolt, which secures the alternator
rotor on to the end of the crankshaft. This bolt is
drilled throughout its length, and communicates
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16. Lubrication System
Lubrication is by the Royal Enfield Dry
Sump system which is entirely automatic and
positive in action. The oil tank is integral with
the crankcase, ensuring the full rate of
circulation immediately the engine is started and
rapid heating of the oil in cold weather.
There are two positively driven piston type
oil pumps running at 1/6 engine speed, one at
the rear of the timing cover for pumping oil to
the bearings under pressure and the other at the
front for returning the oil from the crankcase to
the tank. The return pump has a capacity
approximately double that of the feed pump
which ensures that oil does not accumulate in
the crankcase.
The oil from the big ends drains into the
bottom of the crankcase and is prevented by a
baffle from being drawn up by the flywheel.
The oil from the rocker bearings is squirted
through a small hole in the rocker on to the top
end of the push rod. It flows down the push rod
into the cam tunnel where it lubricates the cams
and tappets and thence into the timing chest,
lubricating the timing chains. There are small
holes from the inlet cam tunnel through the
cylinder walls for the purpose of lubricating the
skirts of the pistons and a hole from the inlet cam
Section B11 Page 3
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crankcase pressure to the breather via the hole
drilled through the drive side main journal.
A plug screwed into the head of the bolt
retains the disc, and a hole drilled in its centre
allows the crankcase to breathe into the primary
chaincase.
A vent pipe fitted to the top of the primary
chain case has its aperture inside the case
shielded by a baffle from oil flung from the
chain. (See Fig. 8, Section C.)
The clutch has five pressure plates and four
friction plates, including the sprocket which is
lined on both sides with friction material. The
other friction plates have all Klingerite inserts
on early models.
Later models employ a different friction
material on the friction plate which is first in
order of assembly, to the following two plates.
These have a friction material of a corky
texture.
This assembly gives smooth operation, and
eliminates clutch slip under the most arduous
conditions.
The operating mechanism of the clutch is of
the latest Enfield design, which enables stronger
clutch springs to be used without increasing the
force required to operate it, thus giving
increased load carrying capacity to the clutch.
A description of the operating mechanism is
given in Section E, Sub-section 1.
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18. Gearbox
The gearbox is bolted on to the back of the
crankcase and has four speeds, which are foot
controlled, and a patented neutral finder. All
gears are in constant mesh, changes being
effected by robust dog clutches. (See Section
E).
The standard gear ratios are as follows :Bottom Gear .......... ... ...... ... .. 12.35
Second Gear .......... ... ...... ... .. 8.16
Third Gear
.......... ... ...... ... .. 6.04
Top Gear
... ....... ... ...... ... .. 4.44
19. Clutch
Section B11 Page 4
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The ports in the housing are connected as follows
W - delivery to rocker gear.
Y - suction from oil tank.
X - delivery to big ends.
Z - suction from oil tank.
Position 2. The plunger A is being pushed into the
cylinder hole in the disc C. The port T in the disc
now registers with the delivery port X in the housing,
so that oil is forced out of the cylinder to the big
ends. At the same time the suction port Z in the
housing is uncovered and oil is drawn into the
housing below the disc from the oil tank.
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Position 1. The plunger A is being drawn out of
the cylinder hole in the disc C by the action of the peg
B on the shaft D. The port T in the disc C registers
with the suction port Y in the housing, so that oil is
drawn into the cylinder from the oil tank. At the same
time the delivery port W in the housing is uncovered
and oil below the disc in the housing is forced through
W to the rocker gear.
The ports in the housing are connected as follows :
W' - delivery to oil tank.
Y' - suction from crankcase.
X' - delivery to oil tank.
Z' - suction from timing chest.
Position 1. The plunger A' is being drawn out of
the cylinder hole in the disc C' by the action of the
peg B' on the shaft D'. The port T' in the disc C'
registers with the suction port Y' in the housing, so
that oil is drawn into the cylinder from the crankcase
sump. At the same time the delivery port W' in the
housing is uncovered and oil below the disc in the
housing is forced through W' back to the oil tank.
Position 2. The plunger A' is being pushed into the
cylinder hole in the disc C'. The port T' in the disc
now registers with the delivery port X' in the housing,
so that oil is forced out of the cylinder back to the oil
tank. At the same time the suction port Z' in the
housing is uncovered and oil is drawn into the
housing below the disc from the timing chest.
Section B11 Page 5
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1957 SUPER METEOR
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SECTION C4
Service Operations with Engine in Frame
"Super Meteor"
The correct valve timing at .012 in.
clearance is as follows:
Exhaust opens 75° before bottom dead centre.
Exhaust closes 35° after top dead centre.
Inlet opens 30° before top dead centre.
Inlet closes 60° after bottom dead centre.
3. Tappet Adjustment
The tappet clearance is adjusted by means of
a screw in the outer end of the rocker. Access to
the adjusting screws is obtained by removing
the covers of the rocker boxes.
The clearance between the end of the screw
and the valve stem cap should be nil or as little
as possible with the engine COLD.
To adjust the clearance, loosen the locknut
beneath the rocker arm, turn the screw with a
small spanner and re-tighten the locknut.
The adjustment for each valve should be
made with the corresponding valve of the other
cylinder fully open. This ensures that the tappet
is well clear of the ramp which is located on
either side of the cam to reduce valve noise.
If, after long service, the valve stem cap or
the rocker adjusting screw are found to be worn,
they should be renewed, as uneven thrust due to
the screw being in a different position after
adjustment may cause lateral movement of the
rocker giving rise to a sharp tapping noise.
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4. Ignition Timing
The setting of the ignition depends upon the
position of the sprocket relative to the magneto
shaft.
To obtain access to the magneto sprocket it
is necessary to remove the timing cover (see
Subsection 1).
The sprocket is built into the automatic
advance device and is mounted on a smooth
taper on the magneto shaft. It is held in position
by a nut. (Right Hand Thread.)
To remove the sprocket and auto-advance
device, unscrew the nut and this will draw the
sprocket off.
Before setting the timing remove the rotor
arm of the distributor and adjust the contact
breaker points to a clearance of .015 in. when
fully opened.
Because of the auto-advance mechanism,
the timing is normally in the "retard" position
when the engine is stationary. Rotate the two
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2. Valve Timing
The camshaft sprockets are keyed to the
camshafts so that the valve timing can only be
incorrect if the timing chain is incorrectly fitted.
The correct setting is obtained with the
marks stamped on the camshaft sprockets
facing each other inwards on the centre line and
the mark on the crankshaft sprockets pointing
vertically downwards. If it is necessary to
remove the sprockets see Subsections 23 and
24.
Remember that all three timing sprocket
fixing bolts have Left Hand Threads. While
tightening the camshaft bolts, the sprockets
should be held.
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1. Removal of Timing Cover
First place a tray under the engine to catch
the oil which will escape when the cover is
removed. Remove the timing side exhaust pipe
and the oil filler neck, by taking out the three
screws fixing it to the crankcase. Remove the
timing cover fixing screws. Draw off the timing
cover, tapping it lightly if necessary.
In refitting the cover, insert the two long
screws through the cover to locate the gasket.
See that the thrust washer is on the chain
tensioner sprocket spindle and that the neoprene
seal is in position on the oil feed plug. If the seal
is split or otherwise damaged, a new one should
be fitted, of the latest type, which is captive on
the feed plug. The feed plug is Part No. 42113
and the seal is Part No. 42114. If the plug is
damaged it should be renewed to ensure oil
pressure to the big end bearings.
The refitting of the cover will be facilitated if
the engine is turned gently forwards while the
cover is being put into place. This will help the
engagement of the pump worm with the pump
spindle and prevent damage to the gears.
Always fill the filter with clean oil before
refitting the timing cover and always take great
care not to damage the gasket where the section
is narrow.
To verify that the oil pumps are working
after replacing the timing cover, start the engine
and remove the oil filler cap so that the oil
return pipe can be seen. It may take several
minutes for all the oil passages to fill and the oil
to commence to circulate.
Section C4 Page 1
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Section C4 Page 2
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removing the chain case cover, which is held in
position by a single nut. Before removing the
nut, place a tray under the engine to catch the oil
from the chaincase.
Beneath the bottom run of the chain is a
curved slipper on which the chain rests and
which may be raised or lowered by turning the
adjusting screw after having first slackened the
locknut.
A rubber button is fitted to the end of the
adjusting screw to prevent the transmission of
chain noise to the chaincase and this is held
against the chaincase by a hairpin spring, which
prevents it from bouncing.
After replacing the chain cover, remember
to replenish the chaincase with oil.
Do not adjust the chain to be dead tight but
rotate the engine slowly and, while doing so, test
the tension of the top run of the chain by
pressing it up and down with the fingers. Adjust
the tension so that there is ¼ in. up and down
movement at the tightest spot.
Re-tighten the locknut on the adjusting
screw. Replace the chain cover and replenish
with oil.
6. Timing Chain Adjustment
Before adjusting the tension of the timing
chain, turn the engine until the chain is in its
tightest position and any slack is between the
rear cam sprocket and the timing sprocket on
the engine shaft.
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halves of the coupling relatively to each other
against the springs, i.e. into the "advance"
position, and hold it in this position with a piece
of wire.
To set the timing, turn the engine until the
pistons are 3/8 to 7/16 in. before top dead centre
on the compression stroke of the left hand
cylinder, i.e. with both valves closed.
Insert a thin piece of tissue paper between the
points of the contact breaker and turn the
magneto forwards until the paper can just be
pulled out, making sure that the rotor arm of the
distributor when replaced will be pointing
towards the segment connected to the left hand
sparking plug lead.
Tighten the sprocket and auto-advance
device on to the magneto shaft, taking care that
it does not slip.
Remove the piece of wire holding the auto
advance mechanism.
The timing can be checked by removing the
cap from the magneto and holding the rotor arm
of the distributor in the advanced position, which
is 3/8 - 7/16 in. before top dead centre, without
the necessity of taking off the timing cover.
On no account must the cam be altered
from its original position on the rotor shaft or
the efficiency of the magneto will be affected.
5. Primary Chain Adjustment
The tension of the primary chain can be
checked through the inspection cover in the
primary chain case and, should it require
adjustment, access to the adjuster is gained by
Section C4 Page 3
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tool box.
Remove the two nuts on either side of the
seat attaching it to the frame and lift the seat
and mudguard off.
9. Removal of Petrol Tank
Turn off the petrol tap.
The petrol tank is attached to the frame by a
rubber mounted stud at the front, and is clipped
at the rear to a rubber sleeve surrounding the
top tube. To remove the tank, unscrew one front
attachment nut, tap out the stud and, after
disconnecting the petrol feed pipe, the rear of
the tank can be pulled upwards to release the
clip and then lifted clear of the frame.
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Section C4 Page 4
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8. Removal of Dual Seat and Rear Mudguard
Disconnect the leads to the rear lamp by
pulling out the plugs in the connectors near the
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7. Magneto Chain Adjustment
To adjust the magneto chain tension, remove
the timing cover (see Subsection 1), slacken the
three magneto fixing bolts, slide the magneto
back until the chain has about 3/16 in. up and
down movement, then tighten the fixing bolts.
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The tension of the timing chain is altered by
moving the quadrant after slackening the nut A
which secures it (see Fig. 3). This rotates the
eccentric spindle on which the chain tensioner
jockey sprocket is mounted. Tightening of the
chain is effected by moving the quadrant to the
left.
It is imperative that the quadrant is fitted the
right way round and that the eccentric spindle is
fitted correctly in the quadrant fork. If the chain
tightens when the quadrant is moved to the
right, the tensioner has been wrongly assembled
and may cause damage to the quadrant (see Fig.
4).
In making the adjustment, care must be taken
to see that any backlash in the quadrant is taken
up in the "tightening" direction, i.e., do not
make the chain too tight and then move the
quadrant back slightly, but tighten the chain
progressively until the correct tension is
obtained and then lock the quadrant. If the chain
becomes too tight during adjustment, slacken it
right back and make the adjustment again.
If the chain is maladjusted, it may give rise
to a loud noise which can be mistaken for a
faulty bearing. If such a noise is heard,
therefore, first check the adjustment of the
timing chain.
10. Removal of Cylinder Head
First remove the petrol tank and petrol pipe.
(Subsection 9.)
The dual seat may also be removed if
desired (Subsection 8.)
Disconnect the head steady link.
Disconnect the oil pipes and plug lead.
Remove the exhaust pipes and carburettor
and induction pipe.
Remove the rocker box covers.
Turn the engine until both valves are closed.
Remove the five cylinder head nuts and lift
off the head.
In replacing the head, see that the dowels are
in position in the cylinder barrel and that the
push rods are the right way up (shallow cups
upwards).
Apply a thin coat of jointing compound to
both sides of the gasket and place it in position.
Lower the cylinder head over the push rods,
making sure that the rockers locate in the push
rod cups.
Fit the head nuts and washers and partially
tighten down.
When both heads have reached this stage, fit
the induction pipe and tighten the nuts. The
cylinder head nuts can now be finally tightened
down progressively and diagonally from one
side to the other to prevent distortion. After the
engine has been run long enough to get
thoroughly hot, the tightness of the nuts should
be re-checked.
11. Removal of Valves
Remove the rocker-box covers, each held by
four nuts, swing the rocker clear of the valve
and lift or prise away the hardened steel thimble
or end cap. If this has stuck, it can be removed
by means of a screwdriver. Using a suitable
valve spring compressing tool, compress the
valve springs and remove the split conical
collets from the end of the valve stem. Slacken
back the compressing tool and release the
springs. Withdraw the valve and place its
springs, top spring collar (and bottom collar if it
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should be fitted in order to maintain the
interference. It is necessary to re-cut the valve
seat and grind in the valve after a guide has been
replaced. (See Subsection 18.)
A worn exhaust valve guide may give rise to
slight smoking from the exhaust pipe due to oil
passing down the valve stem on to the hot valve
head. This may also be caused or increased by
faulty operation of the breather.
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is loose) and split conical collets together in
order that they may be re-assembled with the
valve from which they were removed.
Deal similarly with the other valves in the
heads.
If the valve will not slide easily through the
valve guide, remove any slight burrs on the end
of the valve stem with a carborundum stone. If
the burrs are not removed and the valve is
forced out, the guide may be damaged.
14. Renewal of Sparking Plug Inserts
A steel thread insert is fitted into each
sparking plug bore to prevent damage to the
threads in the alloy cylinder heads.
This insert should not normally require
renewal but if it does become damaged, for
instance by a faulty plug, it can be pulled out
with a pair of pliers and a new one fitted.
To fit a new insert a special tool T.2142,
consisting of a piece of 7/16 in. diameter tube
or rod with a slot cut in the end is required.
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The new insert is placed over the tool with
the tag engaging in the slot and it is screwed into
the plug hole in the cylinder head from the
outside until the last coil is 1 to 1.1/2 threads
below the top face. A reverse twist of the tool
will then break off the tag.
If the cylinder head has not been removed
from the engine, care must be taken not to drop
the end of the tag into the cylinder and in such a
case it is better to break off the tag with a pair of
long-nosed pliers.
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13. Removal of Valve Guides
To remove the valve guides from the heads
two special tools are required which can easily
be made.
The first is a piece of tube with an internal
bore of not less than 7/8 in.
The second is a mandrel about 4 in. long
made from 9/16 in. diameter bar with the end
turned down to about 5/16 in. diameter for 1/2
in.
Support the cylinder head on the tube which
fits over the collar of the valve guide. Using the
mandrel force the guide out of the head with a
hand press or by using a hammer.
To fit a new guide, support the head at the
correct angle and use a hand press and the same
mandrel. If a hand press is not available and the
guide is replaced by a hammer, use a piece of
tube of 9/16 in. internal diameter to prevent
damage to the bore of the guide. If a valve guide
is removed for any reason, an oversize one
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12. Removal of Rockers
To remove the rocker, first take off the
cylinder head. Remove the hexagon plug on the
inner side and the rocker spindle may be drawn
out by means of a bolt screwed into the rocker
spindle, which is tapped 5/16" B.S.F.
On re-assembling make sure that the spring
washers are fitted on the sides of the rockers
nearest the centre of the engine and the plain
thrust washers on the outer sides.
15. Removal of Cylinders
When the cylinder heads have been removed
the cylinders can be lifted clear of the studs.
This should be done with the pistons at bottom
dead centre.
Section C4 Page 5
18. Grinding-in Valves
To grind a valve, smear the seating with a
little grinding-in compound, place a light, short
coil spring over the valve stem and beneath the
head, insert the valve into its appropriate guide,
press it on to the seat using a tool with a suction
cup and with a backwards and forwards rotary
motion, grind it on to its seat. Alternatively, a
tool which pulls on the valve stem can be used.
Frequently lift the valve and move it round so
that an even and true seating is obtained. If no
light spring is available, the lifting will have to
be done by hand. Continue grinding until a
bright ring is visible on both valve and seating.
The faces and seats of the exhaust valves are
cut at 45 degrees but the profiles of the inlet
valves are of a special streamlined design which
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Section C4 Page 6
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16. Removal of Pistons
Remove the cylinder heads and cylinders.
With a tang of a file remove one of the wire
circlips retaining the gudgeon pins. If necessary
rotate the engine slightly until the pistons are in
such a position that the gudgeon pins will clear
the long cylinder studs when being withdrawn.
Use Special Tool No. E.5477 to extract the
gudgeon pin or using a rod about 1/4 in. in
diameter insert this right through one gudgeon
pin and drive the other pin out of its piston,
supporting the connecting rod substantially
meanwhile to prevent distortion.
Having lifted the first piston away, the other
one may be readily removed in the same
manner. Mark the pistons and gudgeon pins so
that they go back into the same pistons the same
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When replacing the cylinders, clean off the
joint faces and fit new paper joints, two to each
cylinder.
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way round and so that the pistons go back into
the same barrels the same way round.
Take care not to drop the gudgeon pin circlip
into the crankcase. A clean cloth should be put
over the mouths of the crankcase to prevent
this.
17. Decarbonising
Having removed the cylinder heads as
described in Subsection 10, scrape away all
carbon, bearing in mind that you are dealing
with aluminium which is easily damaged.
Scrape gently and avoid scoring the combustion
chamber or the valve seats which are of
austenitic iron shrunk into the head. Be careful
while performing this work not to injure the
joint faces which bed down on to the head
gaskets.
Do not, in any circumstances, use caustic
soda or potash for the removal of carbon from
aluminium alloy.
Scrape away all carbon from the valve heads
and beneath the head, being very careful not to
cause any damage to the valve faces.
If the piston rings are removed the grooves
should be cleaned out and new rings fitted. For
cleaning the grooves, a piece of discarded ring
thrust into a wooden handle and filed to a chisel
point is a useful tool.
If the piston ring gaps exceed 1/16 in. when
the rings are in position in the barrel, new rings
should be fitted. The correct gap for new rings
is .011-.015 in. The gap should be measured in
the least worn part of the cylinder, which will
be found to be the extreme top or bottom of the
bore.
While the cylinders and pistons are not in
position on the engine, cover the crankcase with
a clean cloth to prevent the ingress of dust and
dirt of all kinds. Do not, of course, attempt to
scrape the carbon from the pistons when the
mouths of the crankcase are open.
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cylinder base and cylinder head. Two paper
gaskets are fitted to the base of each cylinder.
Smear clean oil over the pistons, having
replaced the rings if these have been removed,
lower the piston over the connecting rod and
insert the gudgeon pin from the outer side. Fit
the circlip and then fit the second piston in a
similar manner.
Check the piston ring gaps to find out
whether excessive wear has taken place (see
Subsection 17).
Oil the cylinder bores and lower the barrels
over the pistons and seat them gently on their
gaskets.
Drop the push rods down their tunnels on to
the tappet heads, shallow cups upwards.
Fit the copper cylinder head gaskets and see
that the dowels are in position.
Replace the cylinder heads as described in
Subsection 10.
After the engine has been assembled, run it
for a brief period at a speed which will ensure
that the ignition has been advanced by the
automatic advance device. If it is run too slowly
"blueing" of the exhaust pipes may take place.
After the engine has been run for some time
and has become thoroughly hot, go over all the
cylinder head and other nuts to ensure that they
are tight.
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19. Re-Assembly after Decarbonising
Before building up the engine, see that all
parts are scrupulously clean and place them
conveniently to hand on a clean sheet of brown
paper.
It is advisable to fit new gaskets to the
or
eliminates pockets and sharp edges and allows a
smooth flow of gas without eddies.
If the inlet valves or their seats are pitted and
require recutting, care must be taken to
reproduce the correct profile as shown in Fig. 8.
The cylinder heads should preferably be
returned to the works for the inlet valve seats to
be re-cut, but, if this is not possible, a special
tool consisting of an arbor No. T 2053 and cutter
No. T 2054 is available. Great care must be
exercised in using this tool, as it is located off
the valve guides and these may be damaged if
suitable apparatus is not employed.
The inlet valve faces and seats can be cut at
45 degrees in cases of expediency but this may
have a deleterious effect on the performance of
the engine.
20. Cleaning the Oil Filters
The oil filter is located in the timing cover
immediately below the oil pumps and is in the
feed circuit to the big ends.
The filter element is removed by unscrewing
the nut holding the end cap in position. When
re-assembling the filter after cleaning, take care
that no grit or other foreign matter is sticking to
it. The aluminium cylinder fitted over the rod
inside the filter element is to reduce the free
space which has to be filled after cleaning
before oil reaches the big ends. After emptying
the filter chamber it is essential to run the
engine slowly for about five minutes to ensure
that oil is reaching the big ends.
The felt element should be taken out and
washed in petrol after the first 500 miles and
after every subsequent 2,000 miles. Fit a new
element every 5,000 miles.
21. Overhaul of Oil Pumps
Remove the timing cover as described in
Subsection 1.
Remove the end plates from both pumps.
Remove the pump discs and plungers.
Remove the pump spindle which can be
pulled out from the front or return pump end.
Section C4 Page 7
23. Removal of Pump Worm and Timing
Sprocket
Remove the timing chains (Subsection 22).
Unscrew the oil pump worm by means of the
hexagon head behind it. This is a Left Hand
Thread.
Withdraw the timing sprocket using Special
Tool No. E.4869. Do not attempt to withdraw
the sprocket by tapping the worm as this will
dislodge the locking nut in the crankshaft. (See
Section D, Subsection 6.)
24. Removal of Camshaft Sprockets
Remove the timing chains (Subsection 22).
Unscrew the camshaft sprocket fixing bolt,
which has a Left Hand Thread, at the same time
holding the sprocket.
Withdraw the sprocket by means of a
suitable extractor.
25. Removal of Magneto Sprocket
Remove the timing cover and unscrew the
nut securing the automatic advance mechanism.
This will draw off the sprocket and
auto-advance device from the magneto shaft.
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Check the fit of the plungers in the pump
discs which should have a minimum of
clearance but should be able to be moved in and
out by hand.
If, when fitting a new disc or plunger, the
plunger is found to be too tight a fit, carefully
lap with metal polish until it is just free. If the
pump disc is not seating properly or if a new
pump disc is being fitted, it should be lapped to
the seating with Special Tool No. E.5425, using
Carborundum 360 Fine Paste or liquid metal
polish until an even grey surface is obtained.
Wash all passages, etc., thoroughly with
petrol after lapping to remove all traces of
grinding paste.
The feed pump spring is stronger than that in
the return pump and care must be taken to see
that they are not interchanged. The feed pump is
at the rear or on the right-hand side looking on
the timing cover.
Check the pump disc springs for fatigue by
assembling in the timing cover and placing the
pump covers in position. If the springs are
correct, the pump cover should held ¼ in. off
the timing cover by the feed pump spring and
1/8 in. off by the return pump spring.
The pump spindle should be renewed if
excessive wear has taken place on the teeth.
Re-assemble the oil pumps, replacing the
paper cover gaskets if necessary. Before fitting
each cover fill the pump chamber with clean oil.
Having assembled the pumps, lay the timing
cover flat and fill the oil ports by means of an
oilcan. Turn the pump spindle with a screw
driver in a clockwise direction looking on the
front and it can then be seen whether the pumps
are operating correctly.
Fill the filter chamber with clean oil and
replace the timing cover, taking great care not to
damage the gasket where the section is narrow.
When the timing cover has been refitted on
the engine, the oil feed to the big ends can be
checked by partially unscrewing the feed plug
in the timing cover between the oil pumps. The
oil return to the tank can be checked by
removing the oil filler cap. The feed to the
rockers can be observed by removing the
rocker-box covers, when oil will be seen
flowing down the surface of the push rods.
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22. Removal of Timing Chains
Loosen the magneto fixing bolts.
Remove the magneto sprocket (Subsection 4).
Lift the magneto chain off the cam sprocket.
Loosen the chain tensioner locknut and stud.
Lift the adjusting plate clear of the chain
tensioner spindle.
Remove the chain tensioner spindle and
sprocket.
Lift the chain off the sprockets.
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26. Removal of Engine and Clutch Sprockets.
The primary chain is endless so that it is
necessary to remove both the engine and clutch
sprockets simultaneously.
Remove the alternator stator by undoing
three fixing screws.
Remove the central hexagon nut securing
the alternator rotor, which can then be drawn
off, taking care not to lose the key.
Unscrew the engine sprocket nut using
Special Tool No. E.4877. The engine sprocket
is mounted on splines and can then be removed
with the clutch sprocket.
To remove the clutch sprocket unscrew the
three clutch spring pins then lift away the spring
cap, springs and distance pieces, clutch front
plate, centre retaining ring and the assembly of
driving and driven clutch plates. The clutch
sprocket can then be withdrawn from the centre
after removal of the large circlip which secures
it.
When replacing the engine sprocket, take
care that the felt washer is not nipped behind
the sprocket. This would make the engine very
stiff to turn over and would damage the washer
and allow leakage from the crankcase.
27. Removal of Tappets and Guides
It is only necessary to remove the tappets
and guides if they have become worn.
Remove the cylinder heads and barrels.
(Subsections 10 and 15).
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Extract the tappet guides, using Special Tool
No. E.5790, having heated the case first.
The guides are made from Nickel Chrome
Alloy Iron and if a guide should break while
removing it, it can be withdrawn with a pair of
pliers if the crankcase is heated locally with a
blowlamp. Otherwise it is necessary to
dismantle the crankcase and drive the tappet and
guide out from underneath using a heavy bar in
the cam tunnel.
The guide should have an interference of
0.015 to 0.025 in. in the crankcase and can be
driven in with a bronze drift, care being taken
when the guide is nearly home to avoid breaking
the collar.
If a tappet guide is taken out it should be
replaced by an oversize one.
32. Oil Pipe Unions
The oil feed to the rocker gear is through
pipes from unions at the back of the crankcase
below the cylinder base to unions on the
cylinder heads. The unions are fitted with steel
wire thread inserts to prevent the threads in the
aluminium from stripping.
The method of fitting the thread inserts is
the same as that used for the sparking plug
inserts described in Subsection 14.
33. Rocker Oil Feed Relief Valves
There is a pressure relief valve in the oil
supply to the rocker gear, whose function is to
prevent excessive pressure and whose setting is
not critical.
The valve is located in the crankcase face
behind the timing cover and consists of a 3/16
in. diameter steel ball held in position by a
spring and a brass plug.
The valve is set before leaving the Works
and should not normally require to be disturbed
but, if it is found necessary to dismantle it, it
can be reset by screwing the plug in until it is
flush with the face of the crankcase, which will
cause the pressure to be relieved at
approximately 10 lbs. per square inch. The plug
is prevented from moving by peening over the
aluminium into the screwdriver slot with a small
centre punch.
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31. Removal of Bearing Housing Felt Washer
Remove the engine sprocket, clutch and rear
half of the primary chain case.
The felt washer is located in the steel
housing at the back of the chain case.
34. Fitting the Alternator
The alternator consists of two parts, the
stator and the rotor. The stator is mounted on
the back half of the primary chaincase, being
held in position by three studs and distance
pieces. The rotor, which contains the permanent
magnets is mounted by means of an adaptor on
the end of the crankshaft and is secured by a
stud and nut and located by a key.
The radial air gap between the rotor and the
poles of the stator should be .020 in. in all
positions and care must be taken when re-fitting
to see that it is not less than .010 in. at any
point.
Fit the rotor first, making sure that it is
located concentrically on the end of the
crankshaft. Attention must be given to the
seating of the key because a badly-fitting key
may cause the rotor to run unevenly. The nut
holding the rotor in position is secured by a tab
washer.
Having fitted the rotor, place the three
distance collars over the three studs in the
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30. Removal of Final Drive Sprocket
Remove the clutch as described in
Subsection 29.
Remove the primary chain tensioner.
Remove the rear half of the primary chain
case by taking out three socket screws.
Remove the grub screw locking the final
drive sprocket nut.
Hold the sprocket and remove the nut (Right
Hand Thread). The sprocket can then be
withdrawn.
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29. Removal of Clutch
Remove the engine sprocket and clutch
sprocket together as described in Subsection 26.
To remove the clutch hub, hold the clutch
with Special Tool No. E 4871 and remove the
centre retaining nut and washer with a box
spanner.
The hub can then be withdrawn from the
shaft with Special Tool No. E.5414.
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28. Dismantling the Breather
If the breather is not operating efficiently, it
may cause pressure in the crankcase, instead of
a partial vacuum, giving rise to smoking or over
oiling.
See that the discs and back-plate are clean
and undamaged and that the discs are seating
properly.
When re-assembling the breather, apply
jointing compound sparingly to the back of the
steel plate taking great care to keep it away from
the discs or their seatings.
Great care must be taken not to nip the felt
washer behind the sprocket on re-assembly as
this would make the engine very stiff to turn
over and would damage the washer and allow
leakage from the crankcase.
Section C4 Page 9
This is a gauge .015 in. greater in radius than
the rotor and fits over the adaptor on the end of
the crankshaft in the rotor's place.
The stator is then put in position on the stud
in the chaincase and the nuts tightened up.
Remove the gauge and fit the rotor, then
check the air gap.
35. Removal of the Magneto
The magneto is bolted to the timing side
crankcase by the hexagon-headed screws.
Access to these is obtained by removing the
timing cover (Subsection 1) and the magneto
sprocket and automatic advance device
(Subsection 25).
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primary chaincase and put the stator in position
with the coil connections facing outwards.
Replace the nuts and shakeproof washers
only finger tight and insert six strips (preferably
of non-magnetic material) .015 in. thick and
about 1/8 in. wide between the rotor and each
pole piece.
Tighten the stator nuts and withdraw the
strips.
Check the air gap with narrow feelers and, if
less than .010 in. at any point, remove the stator
and file or grind the pole piece carefully until the
correct gap is obtained.
An alternative, and more satisfactory, method
of assembling the alternator requires the use of
Special Tool No. T2055.
Section C4 Page 10
SECTION C11
Service Operations with Engine in Frame
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Remember that all three timing sprocket fixing
bolts have Left Hand Threads. While
tightening the camshaft bolts the sprockets
should be held.
The correct valve timing at -012 in. tappet
clearance is as follows:Exhaust opens 83° before bottom dead centre.
Exhaust closes 35° after top dead centre.
Inlet opens 24° before top dead centre.
Inlet closes 73° after bottom dead centre.
3. Tappet Adjustment
The tappet clearance is adjusted by means of
a screw in the outer end of the rocker. Access to
the adjusting screws is obtained by removing
the covers of the rocker boxes.
The clearance between the end of the screw
and the valve stem should be nil or as little as
possible with the engine COLD.
To adjust the clearance, loosen the locknut
beneath the rocker arm, turn the screw with a
small spanner and re-tighten the locknut.
The adjustment of each valve should be
made with the corresponding valve of the other
cylinder fully open. This ensures that the tappet
is well clear of the cam.
If, after long service, the rocker adjusting
screws are found to be worn, they should be
renewed, as uneven thrust due to the screw
being in a different position after adjustment
may cause lateral movement of the rocker,
giving rise to a sharp tapping noise.
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3A. Removal of the Camshafts
Remove the timing cover (Subsection 1).
Remove the cam sprockets (Subsection 24).
Remove the three screws holding each of the
camshaft bearing housings.
Compress the valve springs and withdraw
the camshafts. It is necessary to rotate the
camshafts slightly while withdrawing them in
order that the cams will pass through the shaped
hole in the crankcase.
When replacing the camshafts compress the
valve springs and hold the tappets clear of the
cams. If the rocker adjusting screws are
screwed right back, it is not necessary to
compress the valve springs.
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2. Valve Timing
The camshaft sprockets are keyed to the
camshafts so that the valve timing can only be
incorrect if the timing chain is incorrectly fitted.
The correct setting is obtained with the
marks stamped on the camshaft sprockets facing
each other inwards on the centre line and the
mark on the crankshaft sprocket pointing
vertically downwards. If it is necessary to
remove the sprockets see Subsections 23 and 24
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1. Removal of the Timing Cover
First place a tray under the engine to catch
the oil which will escape when the cover is
removed. Remove the timing side exhaust pipe.
Remove the oil filler neck by taking out the
three screws fixing it to the crankcase. Remove
the timing cover fixing screws. Draw off the
timing cover, tapping it lightly if necessary.
In refitting the cover, insert the two long
screws through the cover to locate the gasket.
See that the thrust washer is on the chain
tensioner sprocket spindle and that the neoprene
seal is in position on the oil feed plug. If the
seal or plug is damaged a new one of either
should be fitted. The seal is Part No. 42114 and
the plug is Part No. 42113. (This seal can get
damaged due to poor alignment of the
crankshaft and oil feed plug. There is a
modification available to alleviate this
problem).
The refitting of the cover will be facilitated
if the engine is turned gently forwards while the
cover is being put into place. This will help the
engagement of the pump worm with the pump
spindle and prevent damage to the gears.
Always fill the filter with clean oil before
refitting the timing cover and always take great
care not to damage the gasket where the section
is narrow.
To verify that the oil pumps are working
after replacing the timing cover, start the engine
and slacken the feed plug between the oil
pumps. The return oil pump can be checked by
removing the oil filler cap so that the oil return
pipe can be seen. It may take several minutes
for all the oil passages to fill and the oil to
commence circulating. The feed to the rockers
can be observed by removing the rocker-box
covers, when oil will be seen flowing down the
surface of the push rods.
4. Ignition Timing
To set the ignition timing, first remove the
timing cover (subsection 1) and then remove
Section C11 Page 1
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the magneto sprocket nut and withdraw the
sprocket, using Special Tool No. 14835.
Set the contact points to .012 in., fully
opened, but if they are worn or pitted refer to
Section G.
Remove the sparking plugs and set the piston
in the left-hand cylinder to 3/8 in. before top
dead centre on the compression stroke (i.e., with
both valves closed).
Set the contacts to be just breaking with the
ignition control fully advanced.
Replace the driving sprocket and tighten the
nut.
Replace the timing cover.
(To determine the point at which the
contacts are just breaking, insert a piece of
tissue paper between them and rotate the
contact-breaker in an anti-clockwise direction
until the paper can just be pulled out.)
left.
It is imperative that the quadrant is fitted the
right way round and that the eccentric spindle is
fitted correctly in the quadrant fork. If the chain
tightens when the quadrant is moved to the
right, the tensioner has been wrongly assembled
and may cause damage to the quadrant (see Fig.
3).
In making the adjustment, care must be
taken to see that any backlash in the quadrant is
taken up in the "tightening" direction, i.e., do
not make the chain too tight and then move the
quadrant back slightly, but tighten the chain
progressively until the correct tension is
obtained and then lock the quadrant. If the
chain becomes too tight during adjustment,
slacken it right back and make the adjustment
again.
If the chain is too slack it may give rise to a
loud noise which can be mistaken for a faulty
bearing. If it is too tight the result will be a high
pitched howl. If such noises are heard, therefore,
first check the adjustment of the timing chain.
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6. Timing Chain Adjustment
Before adjusting the tension of the timing
chain, turn the engine until the chain is in its
tightest position, checking the chain between all
sprockets.
Adjust the tension so that there is 1/4 in.
movement of the chain.
The tension of the timing chain is altered by
moving the quadrant after slackening the nut A
which secures it (see Fig. 2). This rotates the
eccentric spindle on which the chain tensioner
jockey sprocket is mounted. Tightening of the
chain is effected by moving the quadrant to the
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5. Primary Chain Adjustment
The tension of the primary chain can be
checked through the inspection cover in the
primary chain case and, should it require
adjustment, access to the adjuster is gained by
removing the chain case cover, which is held in
position by a single nut. Before removing the
nut, place a tray under the engine to catch the oil
from the chaincase.
Beneath the bottom run of the chain is a
curved slipper on which the chain rests and
which may be raised or lowered by turning the
adjusting screw after having first slackened the
locknut.
A rubber button is fitted to the end of the
adjusting screw to prevent the transmission of
chain noise to the chaincase and this is held
against the chaincase by a hairpin spring, which
prevents it from bouncing.
Do not adjust the chain to be dead tight but
rotate the engine slowly and, while doing so,
test the tension of the top run of the chain by
pressing it up and down with the fingers. Adjust
the tension so that there is 1/4 in. up and down
movement at the tightest spot.
Re-tighten the locknut on the adjusting
screw, replace the chain cover and replenish
with oil.
7. Magneto Chain Adjustment
To adjust the magneto chain tension, remove
the timing cover (see Subsection 1), slacken the
three magneto fixing nuts, slide the magneto
back until the chain has about 3/16 in. up and
down movement, then tighten the fixing nuts.
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8. Removal of the Dual Seat and Rear
Mudguard
Disconnect the leads to the rear lamp by
pulling out the plugs in the connectors near the
tool box.
Loosen the two nuts on either side of the seat
attaching the mudguard carrier to the frame and
lift the seat, mudguard and carrier off together.
9. Removal of the Petrol Tank
Remove the petrol tank by detaching the
petrol pipe and removing the rubber mounted
stud which secures the front of the tank to the
frame. With early models release the bottom
section of the rear clip by unscrewing the two 1/4
in. attachment nuts. Tap out the two studs and
raise the rear of the tank to release the clip. The
tank may then be removed.
With later models the rear tank attachment is
in the form of a laterally situated bracket with a
rubber block fixed to it, this bears against the
underside of the frame top tube, drawing the
tank down on to the rubber covering of the top
tube.
To remove, unscrew the two bolts securing
the bracket and lift the tank clear.
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10. Removal of the Cylinder Head
First remove the petrol tank and petrol pipe.
(Subsection 9.)
The dual seat may also be removed if
desired. (Subsection 8.)
Disconnect the head steady link (early
models).
Remove head steady brackets (later models).
Disconnect the oil pipes and plug leads.
Remove the exhaust pipes and carburettor(s)
and induction manifold.
Remove the rocker box covers.
Turn the engine until both valves are closed.
Remove the five cylinder head nuts from
each head and lift off.
In replacing the heads, see that the dowels are
in position in the cylinder barrels and that the
push rods are the right way up (shallow cups
upwards).
Apply a thin coat of jointing compound to
both sides of the gasket and place it in position.
Lower the cylinder heads over the push rods,
making sure that the rockers locate in the push
rod cups.
Fit the head nuts and washers and partially
tighten down.
When both heads have reached this stage, fit
the induction pipe and tighten the nuts. The
cylinder head nuts can now be finally tightened
down progressively and diagonally from one
side to the other to prevent distortion. After the
engine has been run long enough to get
thoroughly hot, the tightness of the nuts should
be rechecked.
11. Removal of the Valves
Having removed the cylinder head, remove
the rockerbox covers, each held by four nuts,
and swing the rocker clear of the valve. Using a
suitable valve spring compressing tool,
compress the valve springs and remove the split
collets from the end of the valve stem. Slacken
back the compressing tool and release the
Section C11 Page 3
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tube of 9/16 in. internal diameter to prevent
damage to the bore of the guide. If a valve
guide is removed for any reason, an oversize
one should be fitted in order to maintain the
interference. It is necessary to re-cut the valve
seat and grind in the valve after a guide has
been replaced. (See Subsection 18.)
A worn exhaust valve guide may give rise to
slight smoking from the exhaust pipe due to oil
passing down the valve stem on to the hot valve
head. This may also be caused or increased by
faulty operation of the breather.
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15. Removal of the Cylinders
When the cylinder heads have been removed
the cylinders can be lifted clear of the studs. This
should be done with the pistons at top dead
centre.
It is advisable to put a clean cloth over the
mouth of the crankcase to prevent anything,
such as a piece of broken piston ring, from
falling in.
When replacing the cylinders, clean off the
joint faces and fit new paper joints, two to each
cylinder.
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13. Removal of the Valve Guides
To remove the valve guides from the heads
two special tools are required which can easily
be made.
The first is a piece of tube with an internal
bore of not less than 7/8 in.
The second is a mandrel about 4 in. long
made from 9/16 in. diameter bar with the end
turned down to about 5/16. diameter for 1/2 in.
Support the cylinder head on the tube which
fits over the collar of the valve guide. Using the
mandrel force the guide out of the head with a
hand press or by using a hammer.
To fit a new guide, support the head at the
correct angle and use a hand press and the same
mandrel. If a hand press is not available and the
guide is replaced by a hammer, use a piece of
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12. Removal of the Rockers
To remove the rocker, first take off the
cylinder head. Remove the hexagon plug on the
inner side, and the rocker spindle may be drawn
out by means of a bolt screwed into the rocker
spindle, which is tapped 5/16" B.S.F.
On re-assembling make sure that the spring
washers are fitted on the sides of the rockers
nearest the centre of the engine and the plain
thrust washers on the outer sides.
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springs. Withdraw the valve and place its
springs, top spring collar (and bottom collar if it
is loose) and split collets together in order that
they may be re-assembled with the valve from
which they were removed.
Deal similarly with the other valves in the
heads.
If the valve will not slide easily through the
valve guide, remove any slight burrs on the end
of the valve stem with a carborundum stone. If
the burrs are not removed and the valve is forced
out, the guide may be damaged.
14. Removal of the Sparking Plugs
Care must be taken when removing and
replacing the sparking plugs not to damage the
threads in the cylinder heads.
If the threads do become damaged, they can
be tapped out to a larger size and steel wire
inserts fitted.
Special tools are available for tapping and
inserting the steel wire inserts. The latter tool
consists of a piece of 7/16 in. diameter tube or
rod with a slot cut in the end.
The insert is placed over the tool with the tag
engaging in the slot and it is screwed into the
plug hole in the cylinder head from the outside
until the last coil is 1 to 1.1/2 threads below the
top face. A reverse twist of the tool will then
break off the tag.
If the cylinder head has been removed, the
fitting of the insert will be facilitated if the tool
is put through the hole from the inside and the
insert screwed back from the outside.
If the cylinder head has not been removed,
care must be taken not to drop the end of the tag
into the cylinder and in such a case it is better to
break off the tag with a pair of long-nosed
pliers.
Note: Engines with a Number prior to
SMSA 6800 have short reach plugs, in which
case wire inserts are fitted as standard.
16. Removal of Pistons
Remove the cylinder heads and cylinders.
With a tang of a file remove the two outer
circlips retaining the gudgeon pins. Remove the
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long central cylinder studs which come opposite
the gudgeon pins.
Use Special Tool No. E.5477 to extract the
gudgeon pin or using a rod about 1/4 in. in
diameter insert this right through one gudgeon
pin and drive the other pin out of its piston,
supporting the connecting rod substantially
meanwhile to prevent distortion.
Having lifted the first piston away, the other
one may be readily removed in the same
manner. Mark the pistons and gudgeon pins so
that they go back into the same pistons the same
way round and so that the pistons go back into
the same barrels the same way round.
Take care not to drop the gudgeon pin circlip
into the crankcase. A clean cloth should be put
over the mouths of the crankcase to prevent this.
or
cup and with a backwards and forwards rotary
motion, grind it on to its seat. Alternatively, a
tool which pulls on the valve stem can be used.
Frequently lift the valve and move it round so
that an even and true seating is obtained. If no
light spring is available, the lifting will have to
be done by hand. Continue grinding until a
bright ring is visible on both valve and seating.
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The faces and seats of the exhaust valves are
cut at 45 degrees but the profiles of the inlet
valves are of a special streamlined design which
eliminates pockets and sharp edges and allows a
smooth flow of gas without eddies.
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18. Grinding-in Valves
To grind a valve, smear the seating with a
little grinding in compound, place a light, short
coil spring over the valve stem and beneath the
head, insert the valve into its appropriate guide,
press it on to the seat using a tool with a suction
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17. Decarbonising
Having removed the cylinder heads as
described in Subsection 10, scrape away all
carbon, bearing in mind that you are dealing
with aluminium which is easily damaged.
Scrape gently and avoid scoring the combustion
chamber or the valve seats which are of
austenitic iron shrunk into the head. Be careful
while performing this work not to injure the
joint faces which bed down on to the head
gaskets.
Do not, in any circumstances, use caustic
soda or potash for the removal of carbon from
aluminium alloy.
Scrape away all carbon from the valve heads
and beneath the heads, being very careful not to
cause any damage to the valve faces.
If the piston rings are removed the grooves
should be cleaned out and new rings fitted. For
cleaning the grooves, a piece of discarded ring
thrust into a wooden handle and filed to a chisel
point is a useful tool.
If the piston ring gaps exceed 1/16 in. when
the rings are in position in the barrel, new rings
should be fitted. The correct gap for new rings
is .011-.015 in. The gap should be measured in
the least worn part of the cylinder, which will be
found to be the extreme top or bottom of the
bore.
While the cylinders and pistons are not in
position on the engine, cover the crankcase with
a clean cloth to prevent the ingress of dust and
dirt of all kinds. Do not, of course, attempt to
scrape the carbon from the pistons when the
mouths of the crankcase are open.
If the inlet valves or their seats are pitted and
require recutting, care must be taken to
reproduce the correct profile as shown in Fig. 6.
The cylinder heads should preferably be
returned to the Works for the inlet valve seats to
be re-cut, but, if this is not possible, a special
tool consisting of an arbor No. T 2053 and cutter
No. T2054 is available. Great care must be
exercised in using this tool as it is located off the
Section C11 Page 5
valve guides and these may be damaged if
suitable apparatus is not employed.
The inlet valve faces and seats can be cut at
45 degrees in cases of expediency but this may
have a deleterious effect on the performance of
the engine.
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19. Re-Assembly after Decarbonising
Before building up the engine, see that all
parts are scrupulously clean and place them
conveniently to hand on a clean sheet of brown
paper.
Check the piston ring gaps to find out
whether excessive wear has taken place (see
Subsection 17).
It is advisable to fit new gaskets to the
cylinder base and cylinder head. Two paper
gaskets are fitted to the base of each cylinder.
Smear clean oil over the pistons, having
replaced the rings if these have been removed,
lower the piston over the connecting rod and
insert the gudgeon pin from the outer side. Fit
the circlip and then fit the second piston in a
similar manner.
Oil the cylinder bores and lower the barrels
over the pistons and seat them gently on their
gaskets.
Drop the push rods down their tunnels on to
the tappet heads, shallow cups upwards.
Fit the copper cylinder head gaskets and see
that the dowels are in position.
Replace the cylinder heads as described in
Subsection 10.
After the engine has been assembled, run it
for a brief period at a speed which will ensure
that the ignition has been advanced by the
automatic advance device. If it is run too slowly
"blueing" of the exhaust pipes may take place.
After the engine has been run for some time
and has become thoroughly hot, go over all the
cylinder head and other nuts to ensure that they
are tight.
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20. Cleaning the Oil Filters
The oil filter is located in the timing cover
immediately below the oil pumps and is in the
feed circuit to the big ends.
The filter element is removed by unscrewing
the nut holding the end cap in position. When
re-assembling the filter after cleaning, take care
that no grit or other foreign matter is sticking to
it. The aluminium cylinder fitted over the rod
inside the filter element is to reduce the free
space which has to be filled after cleaning before
oil reaches the big ends. After emptying the
filter chamber it is essential to run the engine
slowly for about five minutes to ensure that oil is
reaching the big ends.
The felt element should be taken out and
washed in petrol after the first 500 miles and
after every subsequent 2,000 miles. Fit a new
element every 5,000 miles.
21. Overhaul of Oil Pumps
Remove the timing cover as described in
Subsection 1.
Section C11 Page 6
23. Removal of Pump Worm and Timing
Sprocket
Remove the timing chains (Subsection 22).
Unscrew the oil pump worm by means of the
hexagon head behind it. This is a Left Hand
Thread.
Withdraw the timing sprocket using Special
Tool No. E.4869.
24. Removal of the Camshaft Sprockets
Remove the timing chains (Subsection 22).
Unscrew the camshaft sprocket fixing bolt,
which has a Left Hand Thread, at the same
time holding the sprocket.
Withdraw the sprocket by means of a
suitable extractor.
25. Removal of the Magneto
Remove the timing cover (Subsection 1).
Remove three fixing nuts.
Lift the chain off the sprocket and withdraw
the magneto and sprocket complete.
26. Removal of the Engine and Clutch
Sprockets
The primary chain is endless so that it is
necessary to remove both the engine and clutch
sprockets simultaneously.
On early models the alternator stator is
removed by undoing the three fixing screws, but
in the case of later types, the smaller diameter
stator must be withdrawn from the adaptor ring
after removing three nuts. The adaptor ring can
then be removed from the primary chain case
when the three screws have been taken out.
Remove the central hexagon nut securing the
alternator rotor, which can then be drawn off,
taking care not to lose the key.
Unscrew the engine sprocket nut using
Special Tool No. E.4877. The engine sprocket is
mounted on splines and can then be removed
with the clutch sprocket.
To remove the clutch sprocket, disconnect
the clutch cable, unscrew three pressure plate
pins and remove the pressure plate assembly,
the centre retaining ring and the assembly of
driving and driven clutch plates. The clutch
sprocket can then be withdrawn from the centre
after the removal of the large circlip which
secures it.
When replacing the engine sprocket, take
care that the felt washer (neoprene on later
models) is not nipped behind the sprocket. This
would make the engine very stiff to turn over
and would damage the washer and allow
leakage from the crankcase. (See Subsection
31.)
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22. Removal of the Timing Chains
Remove the magneto and chain (Subsection
25).
Loosen the chain tensioner locknut and stud.
Lift the adjusting plate clear of the chain
tensioner spindle.
Remove the chain tensioner spindle and
sprocket.
Lift the chain off the sprockets.
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Remove the end plates from both pumps.
Remove the pump discs and plungers.
Remove the pump spindle which can be
pulled out from the front or return pump end.
Check the fit of the plungers in the pump
discs which should have a minimum of
clearance but should be able to be moved in and
out by hand.
If, when fitting a new disc or plunger, the
plunger is found to be too tight a fit, carefully
lap with metal polish until it is just free. If the
pump disc is not seating properly or if a new
pump disc is being fitted, it should be lapped to
the seating with Special Tool No. E.5425, using
Carborundum 360 Fine Paste or liquid metal
polish until an even grey surface is obtained.
Wash all passages, etc., thoroughly with
petrol after lapping to remove all traces of
grinding paste.
Check the pump disc springs for fatigue by
assembling in the timing cover and placing the
pump covers in position. If the springs are
correct, the pump cover should be held 1/4 in.
off the timing cover by the feed pump spring and
1/8 in. off by the return pump spring.
The pump spindle should be renewed if
excessive wear has taken place on the teeth.
Re-assemble the oil pumps, replacing the
paper cover gaskets if necessary. Before fitting
each cover fill the pump chamber with clean oil.
Having assembled the pumps, lay the timing
cover flat and fill the oil ports by means of an
oilcan. Turn the pump spindle with a screw
driver in a clockwise direction looking on the
front and it can then be seen whether the pumps
are operating correctly.
Fill the filter chamber with clean oil and
replace the timing cover, taking great care not to
damage the gasket where the section is narrow.
When the timing cover has been refitted on
the engine, the oil feed to the big ends can be
checked by partially unscrewing the feed plug in
the timing cover between the oil pumps. The oil
return to the tank can be checked by removing
the oil filler cap. The feed to the rockers can be
observed by removing the rocker-box covers,
when oil will be seen flowing down the surface
of the push rods.
Section C11 Page 7
instead of a partial vacuum, giving rise to
smoking or over-oiling.
See that the discs and backplate of the
breather on the crankcase immediately below
the left-hand cylinder are clean and undamaged,
and that the discs are seating properly.
When reassembling the breather, apply
jointing compound sparingly to the back of the
steel plate, taking great care to keep the
compound away from the discs and seatings.
Where fitted, the breather which operates
through the end of the crankshaft, may be
inspected by removing the slotted plug from the
head of the rotor retaining bolt. (See Fig. 8.)
29. Removal of the Clutch
Remove the engine sprocket and clutch
sprocket together as described in Subsection 26.
To remove the clutch hub, hold the clutch
with Special Tool No. E 4871 and remove the
centre retaining nut and washer with a box
spanner.
The hub can then be withdrawn from the
shaft with Special Tool No. E.5414.
30. Removal of the Final Drive Sprocket
Remove the clutch as described in
Subsection 29.
Remove the primary chain tensioner.
Remove the rear half of the primary chain
case by taking out three socket screws.
Remove the grub screw locking the final
drive sprocket nut.
Hold the sprocket and remove the nut (Right
Hand Thread). The sprocket can then be
withdrawn.
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27. Removal of the Tappets and Guides
It is only necessary to remove the tappets
and guides if they have become worn.
Remove the cylinder heads and barrels.
(Subsections 10 and 15.)
Extract the tappet guides, using Special Tool
No. E.5790, having heated the case first.
The guides are made from Nickel Chrome
Alloy Iron and if a guide should break while
removing it, it can be withdrawn with a pair of
pliers if the crankcase is heated locally with a
blowlamp. Otherwise it is necessary to dismantle
the crankcase and drive the tappet and guide out
from underneath using a heavy bar in the cam
tunnel.
The guide should have an interference of
.0015 to .0025 in. in the crankcase and can be
driven in with a bronze drift, care being taken
when the guide is nearly home to avoid breaking
the collar.
When replacing the exhaust valve tappet
guides care must be taken to ensure that the
groove in the timing side exhaust guide comes
opposite the hole to the timing chest otherwise
flooding of the push rod hole in the cylinder will
occur causing over-oiling.
If a tappet guide is taken out it should be
replaced by an oversize one.
28. Dismantling the Breathers
If the breathers are not operating efficiently,
they may cause pressure in the crankcase,
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31. Removal of the Engine Bearing Housing
Felt Washer (Engines prior to SMSA 6964)
Remove the engine sprocket, clutch and rear
half of the primary chain case.
The felt washer is located in the steel
housing at the back of the chain case.
Great care must be taken not to nip the felt
washer behind the sprocket on re-assembly as
this would make the engine very stiff to turn
over and would damage the washer and allow
leakage from the crankcase.
On Engine SMSA 6964 et seq a neoprene oil
seal is fitted and the above does not apply.
32. Oil Pipe Unions
The oil feed to the rocker gear is through
pipes from unions at the back of the crankcase
below the cylinder base to unions on the
cylinder heads.
The tapped holes into which the unions
screw into the aluminium are fitted with steel
wire inserts to prevent the threads in the
Section C11 Page 8
aluminium from stripping.
The method of fitting the thread inserts is the
same as that used for the sparking plug inserts
described in Subsection 14.
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33. Rocker Oil Feed Relief Valve
There is a pressure relief valve in the oil
supply to the rocker gear, whose function is to
prevent excessive pressure and whose setting is
not critical.
The valve is located in the crankcase face
behind the timing cover and consists of a 3/16
in. diameter steel ball held in position by a
spring and a brass plug.
The valve is set before leaving the Works and
should not normally require to be disturbed but,
if it is found necessary to dismantle it, it can be
reset by screwing the plug in until it is flush with
the face of the crankcase, which will cause the
pressure to be relieved at approximately 10 lbs.
per square inch. The plug is prevented from
moving by peening over the aluminium into the
screwdriver slot with a small centre punch.
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34. Fitting the Alternator
The alternator consists of two parts, the
stator and the rotor. The stator of 1960 models
is mounted on to the three studs of the adaptor
ring, which in turn is secured to the back half of
the primary chaincase by three screws.
On earlier models the stator is of greater
diameter and mounted on to the primary
chaincase with three studs and distance pieces.
The rotor, which contains the permanent
magnet, is mounted on the end of the crankshaft
and is located by a key and secured by a special
bolt and spring washer on 1960 models, and by
a nut and tab washer on earlier models.
The radial air gap between the rotor and the
poles of the stator should be .020 in. in all
positions and care must be taken when refitting
to see that it is not less than .010 in. at any point.
Fit the rotor first, making sure that it is
located concentrically on the end of the
crankshaft. Attention must be given to the
seating of the key because a badly fitting key
may cause the rotor to run unevenly. Finally
secure the rotor with the appropriate bolt or nut
and washer.
Having fitted the rotor, secure the adaptor
ring of 1960 models with the three
cheese-headed screws, and shakeproof washers,
or, in the case of earlier models, place the three
distance pieces over the three chaincase studs.
The stator may then be fitted, with the coil
connections facing outwards.
Replace the nuts and shakeproof washers
only fingertight, and insert six strips (preferably
of nonmagnetic material) .015 in. thick and
about 1/8 in. wide between the rotor and each
pole piece.
Tighten the stator nuts and withdraw the
strips.
Check the air gap with narrow feelers and, if
less than .010 in. at any point, remove the stator
and file or grind the pole piece carefully until
the correct gap is obtained.
An alternative, and more satisfactory,
method of assembling the alternator requires the
use of Special Tool No. T2055.
This is a gauge .015 in. greater in radius than
the rotor and fits over the adaptor on the end of
the crankshaft in the rotor's place.
The stator is then put in position on the studs
in the chaincase and the nuts tightened up.
Remove the gauge and fit the rotor, then
check the air gap.
Section C11 Page 9
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1959 SUPER METEOR
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SECTION D10
Service Operations with Engine Removed
Super meteor and Constellation
Disconnect the clutch cable.
Remove the footrest bar.
Remove the bottom rear engine bolt.
Support the engine on a suitable box or
wood block.
Raise the centre stand and remove the
spring.
Loosen the bottom gearbox nuts and swing
the lower engine plates down.
Remove the front engine plates, horn and
stand.
Lift the engine out of the frame.
2. Removal of the Gear Box
Remove the engine sprocket and clutch
(Section C., Subsections 26 and 29).
Remove the rear half of the primary
chaincase by removing three socket screws and
the chain tensioner pivot.
The gearbox can now be withdrawn from the
back of the crankcase after unscrewing the four
nuts which secure it.
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1. Removal of the Engine Gearbox Unit from
the Frame
Disconnect the battery leads.
Remove the dual seat and petrol tank.
Remove the engine steady.
Remove the tool box cover and slide the
flexible connection to the air cleaner off the
induction pipe (where fitted).
Remove the exhaust pipe.
Disconnect the electric horn leads.
Loosen the rectifier bracket and swing the
rectifier clear.
Remove contact breaker cover.
Remove carburettor fixing pins.
Remove the rear chain.
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3. Dismantling the Crankcase
Drain the oil tank by removing the drain
plug.
Having removed the engine from the frame
as described in Subsection 1, dismantle the
heads, barrels, pistons, timing gear, magneto,
etc., as described in Section C.
Remove the gearbox as described in
Subsection 2.
Remove the two hexagon-headed plugs on
the driving side of the crankcase just below the
cylinder base.
On no account must these plugs be disturbed
on early models, unless the driving side cylinder
has been, or is to be, lifted, because they cannot
be tightened without holding the nuts inside.
Later models do not have internal nuts, the holes
in the crankcase being tapped and the plugs,
which have slotted hexagon heads, screw into
them.
Access can now be obtained through the plug
holes to two screws holding the two halves of
the crankcase together which must be removed.
Remove three nuts in the timing chest, two
nuts on the driving side crankcase, two loose
studs through the bottom of the crankcase and
two loose studs through the back of the oil tank.
(The other studs have already been removed to
take the engine out of the frame.)
REMOVAL OF SCREWS IN CRANKCASE
(EARLY MODELS)
Fig. 1
Section D10 Page 1
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Turn the crankshaft until the connecting rods
are at bottom dead centre and the two halves of
the crankcase can then be separated, tapping the
crankcase with a soft mallet.
The inner race of the roller bearings on the
timing side will remain on the crankshaft
bringing with it the cage and rollers and leaving
the outer face fixed to the crankcase.
The inner race of the ball bearing on the
driving side is a tight fit on the shaft and can be
removed with Special Tool No. E.5121. If this is
not available, the shaft can be driven out with a
hide mallet or a soft metal drift.
To avoid damage to the ball bearing the case
should be heated to about 100°C. before doing
this.
6. Re-assembly of the Crankcase
Fit the outer roller race in the timing side
crankcase, the ball-bearing in the driving side
crankcase and the inner roller race on the crankshaft as described in Subsection 4.
Be sure that the inner race is driven on just
flush with the end of the crankshaft and no
further.
There are several methods of assembling the
crankcase. If the timing-side is fitted to the
crankshaft first, care must be taken not to score
the inside of the case. If the driving-side is
fitted first it is possible, with some makes of
roller bearing, though not probable, to drop one
of the rollers into the crankcase and cause
serious damage to the engine.
(a) Timing-side First. Heat the timing-side
crankcase with the outer roller bearing race in
position to about 100° C.
Lay the crankcase flat on the bench and
insert the shaft, with the inner roller race in
position, arranging the connecting rods so that
they do not foul the crankcase.
Insert the camshafts in their correct position
(exhaust front, inlet rear).
Put the distance piece in position on the
driving side of the crankshaft.
Apply jointing compound to the timing side
crankcase.
Heat the driving-side crankcase and bearing
to 100° C. and drop it over the crankshaft,
making sure to lift the tappets clear of the cams.
Bolt the two halves of the crankcase
together. The crankshaft should now be drawn
into its correct position by fitting the engine
sprocket temporarily and tightening the nut
whilst the crankcase is still hot.
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5. Fitting the Connecting Rods
To remove the connecting rods from the
crankshaft, first take out the cotter pins securing
the socket screws in the connecting rods and
then remove the socket screws themselves.
If the big end bearing caps are removed to
examine the condition of the bearings, make
sure that the caps are refitted the same way
round on the same rods and that the rods
themselves are refitted the same way round on
the same crank pins.
In refitting the connecting rods, the socket
screws should be tightened with a torque
wrench set at 200-220 inch-lbs.
If the cotter pins do not come in line remove
the socket screws and use a different thickness
of washer. A difference of .005 in. in the washer
alters the position of the screw approximately
1/8 of a turn.
There is a recess in one side of the
connecting rod for a cotter pin head and this
side must face outwards when the connecting
rod is assembled on the crankshaft to avoid
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4. Main Bearings
To remove the ball bearing from the driving
side crankcase, heat the crankcase to about 100
degrees C. by immersion in hot water or in an
oven after which the bearing can be driven out
using a drift which applies pressure to the
outside race only.
When refitting a new ball bearing, heat the
crankcase in the same way and use the same
drift taking great care to keep the bearing square
with the bore.
To remove the outer roller race from the
timing side crankcase, first heat the crankcase
then drive the race out using a small punch
through the three holes provided.
The inner race and rollers can be withdrawn
from the crankshaft using a claw type extractor.
When refitting the inner race drive it on to
the shaft until just flush with the end and no
further.
fouling between the cotter and the crankshaft
web.
If it is necessary to replace the big ends, a
service crankshaft can be supplied with
connecting rods fitted.
(b) Driving-side First. Support the
crankshaft with the driving end pointing
upwards and place the distance piece in
position. Heat the drivingside crankcase to
about 100° C. and place it over the crankshaft.
Fit the engine sprocket and tighten the nut
while the crankcase is still hot.
Invert the crankshaft and crankcase and support it on two blocks of wood or a large block
with a hole in it.
Insert the camshafts in their correct position
(exhaust front, inlet rear).
Apply jointing compound to the driving-side
crankcase.
Heat the timing-side crankcase (with the
outer roller race) to about 100° C. and drop it
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over the crankshaft, making sure to lift the
tappets clear of the cams.
Bolt the two halves of the crankcase
together.
If so desired the heated timing-side crankcase can be supported on a block or blocks as
before and the crankshaft dropped into it.
Alternatively, the crankshaft can be
supported in a vertical position as above and the
crankcase driven on to it (without heating) by
means of a tubular drift applied to the inner race
of the bearing or the crankcase may be drawn on
to the shaft by means of the sprocket nut with a
temporary distance piece in place of the
sprocket.
8. Pump Worm Threads
If the threads in the crankshaft, into which the
pump worm screws, become damaged, a steel
wire insert can be fitted. The crankshaft should
preferably be returned to the Works for this to be
done or, alternatively, the hole can be drilled out
7/16 in. in dia., using the timing sprocket as a
drill bush and new threads tapped with a special
tool. Note that the thread is left-hand.
The method of fitting the wire insert is the
same as described in Section C, Subsection 14,
for the sparking plugs.
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7. Crankshaft Plugs
The oil passage through the big ends is sealed
by two screwed aluminium plugs locked by
centre punching.
If the crankshaft is taken out of the engine
for any reason, the plugs should be removed and
the oil passage cleared of sludge.
Section D10 Page 3
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1961 SUPER METEOR
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SECTION E4
Gearbox and Clutch
Super Meteor + 1961 Constellation
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1. Removal of Gearbox
This is described in section D, subsection 2. The
gearbox can, however, be completly dismantled with
the engine in the frame except for removal of the
inside operator and the bearings in the gearbox shell.
2. To Dismantle the Gearbox
First remove the kickstart crank, the gear
changelever and the neutral finder and pointer.
Remove the top small inspection cover and
disconnect the clutch cable.
Remove four screws and the gearbox outer
cover can then be detached.
Remove the gear change mechanism by taking
off the two nuts securing it.
Remove the main shaft bearing cover which
is attached by two screws.
Remove four cheese-headed screws and
hexagon bolt.
Remove the spring box locating plunger nut
and washer.
Remove the main shaft nut (Left Hand Thread).
The gearbox inner cover can then be removed
The mainshaft can be drawn straight out if the
clutch has been removed, which, however, should
be done before taking off the gearbox cover.
Section E4 Page 1
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Section E4 Page 2
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(See Section C1 or C2.) The top gear pinion and
dog will come away with the mainshaft.
The layshaft can then be removed and the
2nd and 3rd gears drawn off the final drive
sleeve together with the operator fork.
To take out the final drive sleeve, the final
drive sprocket must be removed and this is
preferably done before removing the inner
cover. (See Section C1 or C2.)
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3. Removal of the Ball Races
The mainshaft ball bearings can be removed
by using a stepped drift 1.7/16 in.–1.11/64 in.
diameter for the bearing in the box and 13/16
in.-39/64 in. diameter for the bearing in the
cover.
When refitting the bearings stepped drifts of
2.5/16 in.-1.11/64 in. diameter and 1.11/16 in.39/64 in. diameter must be used for the bearings
in the box and cover respectively.
Note the felt washer in the recess behind the
larger main shaft bearing and the dished
pen-steel washer between the bearing and the
felt washer. The second dished pen-steel
washer, if fitted, has a smaller central hole and
is on the other side of the main shaft bearing and
is nipped between the inner face of the bearing
and the shoulder on the final drive sleeve. See
that both of the dished pen-steel washers have
their raised portions facing towards the clutch
and final drive sprocket.
If the main shaft top gear pinion and dog
have been removed, make sure that the dog is
replaced the right way round or third and top
gears can be engaged simultaneously.
Make sure that the trunnions on the operator
fork engage with the slots in the inside operator.
See that the main shaft is pushed right home
(It may tighten in the felt washer inside the final
drive shaft nut.)
The layshaft top gear and kickstarter pinion
should be assembled on the layshaft and the
kickstarter shaft and ratchet assembled on to it
before fitting the end cover. Do not forget the
washer on the layshaft between the kickstarter
pinion and the kickstarter shaft.
The joint between the gearbox and the inner
cover should be made with gold size, shellac or a
similar jointing compound.
Make sure that all parts are clean before
commencing assembly. In normal climates the
recesses in the gearbox should be packed with
soft grease and the box should be filled up to the
correct level with gear oil. (See Subsection 9.)
On no account must heavy yellow grease be
used.
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7. Adjustment of the Clutch Control
It is essential that there should be about 1/16
in. free movement in the clutch cable, to ensure
that all the spring pressure is exerted on the
plate.
There are two points of adjustment for the
clutch cable. The first is at the top of the gearbox
just behind the oil filler plug and is provided for
taking up any stretch in the cable. The
adjustment is made by screwing the collar in or
out of the gearbox shell. The connection between
the end of the cable and the horizontal lever can
be seen if the top small inspection cover on the
front of the gearbox is removed. Tighten the
locknut on the screwed collar after adjustment
has been made.
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5. Re-Assembling the Gearbox
The procedure is the reverse of that given in
Subsection 2 but the following points should be
noted:
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4. Gear Change Mechanism
If the two nuts securing the gear change
ratchet mechanism are slackened, the adjuster
plate can be set in the correct position. In this
position the movement of the gear lever
necessary to engage the ratchet teeth will be
approximately the same in each direction.
If the plate is incorrectly adjusted, it may be
found that, after moving from top to third or
from bottom to second gear, the outer ratchets
do not engage the teeth on the inner ratchets
correctly.
If, when fitting new parts, it is found that the
gears do not engage properly, ascertain whether
a little more movement is required or whether
there is too much movement so that the gear
slips right through second or third gear into
neutral. If more movement is required, this can
be obtained by filing the adjuster plate very
slightly at the points of contact with the pegs on
the ratchet ring.
If too much movement is already present, a
new adjuster plate giving less movement must
be fitted.
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6. Dismantling and Re-assembly of the Clutch
The method of removing the clutch is
described in Section C1 or C2.
When re-assembling, note that two of the
steel plates are dished and that the other(s) are
flat. The correct order of assembly is shown on
the exploded drawing.
Do not forget to replace the cush rubber plate
retaining cover before fitting the pressure plate.
Make sure that the distance tubes inside three
of the springs pass through the holes in the
pressure plate. The other three springs are
located by means of bosses on the clutch cap.
Tighten the spring pins as far as they will go
If the clutch lifts unevenly it is probable that one
of the springs has taken a set, in which case new
springs should be fitted.
Section E4 Page 3
The other point of adjustment is behind the
lower inspection cover on the front of the
gearbox and is for compensating for wear on the
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clutch plate inserts. To make the adjustment,
remove the inspection cover, slacken the locknut
and turn the central screw. Tighten the locknut
after adjustment has been made.
The reason for the two points of adjustment
is to enable the lever and fork behind the cover
to be kept in their proper positions whether the
need for adjustment is caused by plate wear or
cable stretch.
Owing to initial bedding down of the clutch
plate inserts, the clutch control may require
adjustment after the first few hundred miles with
a new machine. This point should therefore be
examined soon after delivery and adjustment
made if necessary.
9. Gearbox Oil Level
The gearbox is filled with oil by removing a
plug in the top and the correct level can be
checked by removing a second plug lower down
on the right hand side looking at the cover.
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8. Adjustment of the Neutral Finder
The neutral finder is adjusted by means of an
eccentric stop secured to the front of the
gearbox cover by a bolt which limits the travel
of the operating pedal. Slacken the bolt and turn
the eccentric until the correct movement of the
pedal is obtained.
Section E4 Page 4
SECTION E7
Gearbox and Clutch
1958 – 1960 Constellation
KL engages with two pinions M and N which
are free to rotate or slide on the layshaft G.
The double pinion KL has dogs at each end
which can engage with dogs on the pinion E or
on the pinion J.
The pinions M and N have internal dogs
which can engage or slide over projecting dogs
P and Q on the layshaft G.
The double pinion KL and the pinions M and
N all slide together and are moved by the
operator fork R and are located by a spring
plunger S which engages with a notched plate
which is part of the operator arm R.
The kickstart lever is connected to the pinion
F on the layshaft by a ratchet mechanism which
automatically disengages when the lever is
released.
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2. Description of the Gearbox
The operation of the gearbox is shown
diagrammatically in Fig. 3.
The clutch sprocket A is mounted on the end
of the mainshaft B which passes through the
mainshaft sleeve C on the end of which is the
final drive sprocket D.
At the other end of the mainshaft B is a
pinion E which engages with a pinion F on the
layshaft G. At the other end of the layshaft G is a
pinion H engaging with a pinion J which runs
free on the mainshaft sleeve C.
The mainshaft sleeve C has splines on which
slides a double pinion KL. This double pinion
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1. Description of the Clutch
The clutch is built into the clutch sprocket
and is mounted on the gearbox mainshaft which
projects through into the primary chaincase.
There are five driven plates which are plain
and four driving plates, giving eight friction
surfaces.
The driven plates comprise the clutch centre
backplate, three plain plates on splines on the
clutch centre and the clutch cover plate.
The driving plates comprise the clutch
sprocket itself, which has a ring of friction
material riveted to each side, and three plates
which rotate with it. Early models have all three
plates pierced and fitted with Klingerite inserts,
but later models use a pierced plate with friction
material inserts only on the plate nearest the
clutch sprocket. The other two plates employ a
material particularly resistant to slip, which is
bonded on to both sides of each plate.
The clutch plates are held in contact, when
driving, by six coil springs and are released
when the springs are compressed by the clutch
operating mechanism.
The clutch operating mechanism consists of a
torque arm which is held stationary by a stud in
the chaincase and an operating lever on the same
centre is rotated relatively to the torque arm, with
a scissor-like movement, by the clutch cable
connected to the clutch lever on the handlebar.
Between the operating lever and the torque arm
are four 1/4 in. diameter steel balls in recesses so
that, when the levers are rotated relatively to
each other, the balls are forced out of the
recesses forcing the levers apart and thus
compressing the clutch springs.
Section E7 Page 1
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EXPLODED VIEW OF CLUTCH
Fig. 2
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3. Removal of the Gearbox
This is described in Section D, Subsection 2.
The gearbox can, however, be completely
dismantled with the engine in the frame except
for the removal of the inside operator and the
bearings in the gearbox shell.
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Section E7 Page 2
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5. Removal of the Ball Races
The mainshaft ball bearings can be removed
by using a stepped drift 1.7/16 – 1.11/64 in.
diameter for the bearing in the box and 13/16 –
39/64 in. diameter for the bearing in the cover.
When refitting the bearings stepped drifts of
2.5/16 – 1.11/64 in. diameter and 1.11/16 –
39/64 in. diameter must be used for the bearings
in the box and cover respectively.
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4. To Dismantle the Gearbox
First remove the kickstart crank, the
changegear lever and the neutral finder and
pointer.
Remove four screws and the gearbox outer
cover can then be detached.
Remove the change-gear mechanism, by
taking off the two nuts securing it.
Remove the mainshaft bearing cover which is
attached by two screws.
Remove four cheese-headed screws and one
hexagon bolt.
Remove the spring box locating plunger nut
and washer.
Remove the mainshaft nut (left-hand
thread).
The gearbox inner cover can then be
removed.
The mainshaft can be drawn straight out if
the clutch has been removed, which, however,
should be done before taking off the gearbox
inner cover. (See Section C.) The top gear
pinion and dog will come away with the
mainshaft.
The layshaft can then be removed and the
2nd and 3rd gears drawn off the final drive
sleeve together with the operator fork.
To take out the final drive sleeve, the final
drive sprocket must be removed and this is
preferably done before removing the inner
cover. (See Section C.)
Note the felt washer in the recess behind the
larger mainshaft bearing and the dished
pen-steel washer between the bearing and the
felt washer. (Later gearboxes use a neoprene
seal with a flat washer). The second dished
pen-steel washer, if fitted, has a smaller central
hole and is on the other side of the mainshaft
bearing and is nipped between the inner face of
the bearing and the shoulder on the final drive
sleeve. However this is ommited from later
gearboxes. See that both of the dished pen-steel
washers have their raised portions facing
towards the clutch and final drive sprockets.
6. Change-Gear Mechanism
If the two nuts securing the change-gear
ratchet mechanism are slackened the adjuster
plate can be set in the correct position. In this
position the movement of the gear lever
necessary to engage the ratchet teeth will be
approximately the same in each direction.
If the plate is incorrectly adjusted, it may be
found that, after moving from top to third or
from bottom to second gear, the outer ratchets
do not engage the teeth on the inner ratchets
correctly.
If, when fitting new parts, it is found that the
gears do not engage properly, ascertain whether
a little more movement is required or whether
there is too much movement so that the gear
slips right through second or third gear into
neutral. If more movement is required, this can
be obtained by filing the adjuster plate very
slightly at the points of contact with the pegs on
the ratchet ring.
If too much movement is already present, a
new adjuster plate giving less movement must
be fitted.
7. Reassembling the Gearbox
The procedure is the reverse of that given in
Subsection 4, but the following points should be
noted :
If the mainshaft top gear pinion and dog have
been removed, make sure that the dog is
replaced the right way round or third and top
gears can be engaged simultaneously.
Make sure that the trunnions on the operator
fork engage with the slots in the inside operator.
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Fig. 3A -Neutral. None of the dogs is engaged so that the mainshaft
B and pinions E, F, H, J are rotating but the mainshaft sleeve C and the
final drive sprocket are stationary.
Fig. 3B-Bottom Gear. The sliding pinions K, L, M, N have moved
over so that the dogs on K engage with the dogs on the pinion J. This
causes the double pinion KL, the mainshaft sleeve C and the sprocket D
to rotate with the pinion J which is being driven from the mainshaft
through the layshaft G. The dogs P and Q are not engaged.
Fig. 3C-Second Gear. The sliding pinions have moved so that the
dogs on J are disengaged but the dogs P on the layshaft engage with the
pinion M. The drive from the mainshaft and layshaft then passes
through pinions M and K to the splines on the mainshaft sleeve and the
pinion J is free on the sleeve.
Fig. 3D-Third Gear. The sliding pinions have moved further over so
that the dogs Q on the layshaft engage with the pinion N which drives
the pinion L and thus the mainshaft sleeve, the pinion M being free on
the layshaft.
Fig. 3E-Top Gear. The sliding pinions have now moved right over so
that both sets of dogs P and Q on the layshaft have disengaged but the
dogs on the double pinion KL have engaged with those on the pinion E
and the mainshaft and sleeve rotate together giving a one to one drive
through the gearbox from the clutch sprocket to the output sprocket, the
pinions M, N, J being free to rotate.
OPERATION OF GEARS
Fig. 3
Section E7 Page 3
The joint between the gearbox and the inner
cover should be made with gold size, shellac or
a similar jointing compound.
Make sure that all parts are clean before
commencing assembly. In normal climates the
recesses in the gearbox should be packed with
soft grease and the box should be filled up to the
correct level with engine oil. (See Subsection
11.) On no account must heavy yellow grease
be used.
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See that the mainshaft is pushed right home.
It may tighten in the felt washer inside the final
drive shaft nut.
The layshaft top gear and kickstarter pinion
should be assembled on the layshaft and the
kickstarter shaft and ratchet assembled on to it
before fitting the end cover. Do not forget the
washer on the layshaft between the kickstarter
pinion and the kickstarter shaft.
CUTAWAY SECTION OF GEARBOX
Fig. 4
Section E7 Page 4
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Section E7 Page 5
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8. Dismantling and Reassembling the Clutch
The method of removing the clutch is
described in Section C.
When reassembling the clutch, the following
sequence must be adhered to, after first securing
the clutch sprocket with the large circlip.
Fit the cush rubbers, retaining plates and
three distance tubes, and follow with the
pressure plate assembly as follows:
Plain dished plate (dish projecting outwards).
Friction plate.
Plain flat plate.
Friction plate.
Plain dished plate (dish projecting inwards).
Friction plate.
When reassembling the pressure and outer
plates, see that the three distance tubes are fitted
over the pins securing the outer plate to the
clutch centre and that the six springs are
correctly positioned between the two plates.
Tighten the three pressure plate pins as far as
they will go.
If the clutch lifts unevenly it is probably that
one of the springs has taken a set, in which case
new springs should be fitted.
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9. Adjustment of Clutch
As with any other type of friction clutch,
correct adjustment of the control is essential if
the clutch is to transmit torque without slip and
to free correctly when lifted. Two points of
adjustment are provided-one in the clutch
operating mechanism itself and the other in the
clutch control cable. The adjustment in the clutch
control mechanism must be adjusted so that the
end of the operating lever has about 1/32 in. free
movement. To do this first make sure that there
is plenty of slack in the control cable (or
disconnect it from the handlebar lever) then
loosen the central locknut and rotate the pressure
plate withdrawing pin by means of a screwdriver
slot in its end. Turning this pin clockwise will
increase the clearance in the operating
mechanism; turning it anti-clockwise will take
up the clearance. Lock up the locknut and check
that there is still clearance in the operating
mechanism. This can conveniently be done by
means of a screwdriver in the slot in the end of
the pressure plate withdrawing pin.
Surplus slack in the control cable can now be
taken up by means of a mid cable adjuster which
should be adjusted so that there is about 1/16 in.
free movement on the cable and securely locked
in this position.
(1) If the adjustment in the clutch
operating mechanism is incorrectly adjusted
so that there is no free movement of the
pressure plate withdrawing pin, the clutch
will slip even if plenty of clearance is given to
the control cable.
(2) If excessive clearance is given either in
the operating mechanism or in the control cable
the clutch will drag when lifted.
(3) If excessive clearance is given in the
operating mechanism and this is taken up by
adjusting the control cable, it will be found that
the top of the clutch operating lever knuckle will
bear against the underside of the cable stop
formed on the torque arm before the handlebar
lever comes against the rubber grip. This will
limit the movement of the clutch, which will
drag when lifted.
Access to the adjustment on the clutch
operating mechanism is obtained by removing
the screwed plug from the centre of the primary
chaincase cover.
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10. Adjustment of the Neutral Finder
The neutral finder is adjusted by means of an
eccentric stop secured to the front of the gearbox
cover by a bolt which limits the travel of the
operating pedal. Slacken the bolt and turn the
eccentric stop until the correct movement of the
pedal is obtained.
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11. Gearbox Oil Level
The gearbox is filled with oil by removing a
plug in the top and the correct level can be
checked by removing a second plug lower down
on the left-hand side looking at the cover.
Section E7 Page 6
SECTION F3
Amal 10TT9 Carburetter
If you look up into the bottom of the mixing
chamber when the jet holder has been removed,
the jet choke tube will be seen. This is slotted to
facilitate its removal, which should not be
necessary, however, neither should it be
necessary to remove the choke adaptor, but if it
is removed, take note of the washer beneath it.
Take note, also, of the two washers, one above
and the other below the float chamber
connection to the mixing chamber.
To dismantle the float chamber (it is
assumed that the petrol feed connection has
been broken), remove the float chamber banjo
nut and the banjo, taking care of the washers on
either side of the banjo. Unscrew the two
hexagon headed screws which secure the float
chamber top and remove the latter. This will
release the float needle and give access to the
float in the float chamber. The float guide may
be removed by unscrewing it from below
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1. General Description
This carburetter comprises two main parts,
the mixing chamber and the float chamber. They
are held together by the jet holder, which houses
the main jet and the needle jet. Above these, and
inside the mixing chamber, is the choke adaptor
into which, from below, is screwed the jet choke
tube. Sliding in the mixing chamber and
surrounding the choke adaptor is the throttle
valve (No. 5) and into this is clipped the jet
needle by means of a sliding clip which will fit
into any one of seven grooves. A tapered spring
fits between the throttle valve and the mixing
chamber top, which is secured by a screwed ring
or cap.
At the side of the mixing chamber is a
projecting boss having a narrow slot towards its
lower end. Into the top of this boss a narrow
slide is fitted, spring controlled and connected,
through a cable, to the air lever on the
handlebar.
Screwed into the mixing chamber body just
below the inlet to the engine is the pilot jet
which is spring loaded and controls the slow
running idling speed.
The mixing chamber is mounted on the
cylinder head by a two-bolt flange and the air
intake tube is screwed to the outer face of the
mixing chamber. A spring clip embracing this
tube is used to lock the top cap in position.
Screwed into the base of the float chamber is
a base plug embodying a guide for the float. The
float operates a needle valve seating in the float
chamber top, which is secured to the float
chamber by two screws. A float tickler is
provided and a single banjo, connecting to the
petrol feed, is secured by a large banjo nut.
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2. Dismantling the Carburetter
By unscrewing the top cap from the mixing
chamber, the top, spring, throttle slide and
needle may be withdrawn. To remove the needle
from the slide, pull the copper clip sideways
from the needle groove.
To gain access to the main jet, remove the
hexagon plug from beneath the float chamber
connection; the hexagon bodied main jet may
then be unscrewed. It fits into the jet holder,
which is screwed into the mixing chamber.
Unscrewing the jet holder releases the float
chamber and also gives access to the needle jet,
which is screwed into the top of the jet holder.
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3. Carburation
The “choke” or effective bore of the carburetter
is of great importance for maximum speed. The
design in this carburetter is such that the
maximum volume of air may flow through to
charge the cylinder, also causing the maximum
depression or suction on the jet to supply the
fuel and atomise it.
Needle Control to the Jet. Perfect carburation
throughout the range of the opening of the
throttle means acceleration clean and snappy.
This is where the needle control plays its part;
you have a large main jet for power and for
cooling the engine, and unless it is controlled it
may give you a woolly rich mixture at small
throttle openings -bad for acceleration and plugs.
The needle reduces the flow of petrol above the
main jet, and being taper, it reduces it most at
small throttle openings, and as the throttle is
opened, so the taper allows a bigger flow until
the throttle is about three-quarters open, when
the needle ceases to have any effect, and the
main jet is fully in play.
The needle is attached to the throttle by a
clip, the clip embracing one of seven grooves.
This enables you to tune on the needle once you
have set the main jet for power, by lowering the
needle to get less petrol and vice versa, in its
relation to the throttle opening. The needle is
controlling the fuel flow in a needle jet, which
has an accurately made bore, and this screws
into the bolt that holds the float chamber to the
Section F3 Page 1
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Section F3 Page 2
mixture as it passes through the primary choke
can be handlebar regulated by the air control at
the side of the carburetter, less air being
admitted to enrich the mixture for starting or
atmosphere conditions demanding more liquid
fuel to give the correct mixture strength. As the
engine speed increases at a given throttle
opening so the mixture would tend to get rich,
but as the air flow through the primary choke
above the main jet also increases, there is a
damping effect on the flow of liquid and a
compensated mixture is obtained.
Needle-Jet. Before tuning the carburetter,
confirm that the correct size needle jet is fitted.
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mixing chamber. The standard needle jet bore is
numbered.
The Throttle Valve surrounds the choke
block in the carburetter, and when it is open
leaves a perfectly shaped passage. Apart from
controlling the main jet outlet, it is also used to
control the supply of air to the main jet supply at
low throttle openings-this actual control is by
means of the cut-away on the lower edge of the
intake side of the throttle valve - a smaller
cut-away increasing the mixture strength at
smaller throttle openings and a larger cut-away a
weakening effect.
Throttles with different cut-aways can be
supplied, the number of the cut-away being the
height of the cutaway from the bottom edge
measured in sixteenths of an inch.
Jets. The pilot jet, for starting off with, is
unlike the standard Amal touring pilot jet
because the adjustment regulates the fuel flow
and not the air. This adjustment gives a wider
range for any fuel which is mixed with air
coming through a small hole under the
Carburetter-this mixture for idling and "starting
off" passes through into the carburetter outlet
just behind the throttle, and is again mixed with
air coming under the throttle through the main
bore.
The main jet can be got at easily without
disturbing the float chamber by removing the
hexagon cap under the bolt that holds the float
chamber to the mixing chamber. Main jets are
numbered, the higher the number the larger the
flow; various numbered main jets are available
to suit requirements.
Float Chamber. The float chamber fitted to
the current Model T.T. Carburetter is of a
modified top-feed design incorporating a
large-headed needle and seating, which ensures
that the float chamber is capable of passing 10
gallons an hour, which is more than enough
even when pure alcohol fuel is used.
Consequently, the introduction of this float
chamber has removed the necessity for a double
float chamber as fitted previously.
Locking Devices. Vibration causes parts to
come undone, so we have devised simple and
quick locking devices that are sure, viz. a leaf
spring which is anchored on to the air funnel
and engages the knurled mixing chamber cap,
and a drilled boss for wiring up to hold the float
chamber holding screw to prevent it from
vibrating loose. For the petrol pipe union we
leave you to make your own device.
Compensation and Air Control. The main jet
does not spray directly into the choke bore of the
mixing chamber. It first passes through the
needle jet and is there partially atomised by a
blast of primary air, which can be seen at the
base of the main choke. The richness of the
4. Tuning Instructions
To get carburation for any stated fuel when
the choke bore is correct for the peak revs. of
the engine and the correct needle jet for the fuel
to be used, the procedure is simple. Start off
with an assumed setting, and then tune as
follows. There are four phases
(i) Main jet for power at full throttle.
(ii) Pilot jet for idling.
(iii) Throttle cut-away for "take-off" from
the pilot jet.
(iv) Needle position for "snappy" mixture at
quarter to three-quarter throttle; then
final idling adjustment of the pilot
jet.
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Standard Carburetter Settings
Carburetter Type : Amal 10TT9.
Main Jet : 480.
Needle Jet : - 109.
Choke Bore : 13/16 in.
Throttle Valve : 5.
Needle Position : No. 3 Groove.
Float Chamber : 302/10 Single Banjo.
Always tune in this order, then any
alteration will not upset a correct phase.
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Sequence of tuning. (i) Main jet size. (ii)
Pilot jet adjustment. (iii) Throttle valve
cut-away. (iv) Needle attachment.
(i) Main Jet Size. This should be determined
first: the smallest numbered jet which gives the
greatest maximum speed should be selected,
keeping in mind the safety factor for cooling.
(The air lever should be fully open during these
tests.)
(ii) Pilot Jet Adjustment. Before attempting
to set the pilot adjuster the engine should be at
its normal running temperature, otherwise a
faulty adjustment is possible, which will upset
the correct selection of the throttle valve. The
pilot adjuster, which controls the amount of fuel
passed, is rotated clockwise, to weaken the
Section F3 Page 3
With more cut-away on the air intake side (or
vice versa if weak).
(iv) Jet Needle Position.Tuning sequence
(ii) and (iii) will affect carburation up to somewhere over one-quarter throttle, after which the
needle (which is suspended from the throttle
valve comes into action and when the throttle is
opened, further and tests are again made for rich
or weak spots (as previously outlined) the
needle can be raised to enrich or lowered to
weaken the mixture whichever may be found
necessary. With these adjustments correctly
made, and the main jet size settled, a perfectly
progressive mixture will be obtainable from
tick-over to full throttle.
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mixture, and anti-clockwise to enrich it. Adjust
this very gradually until a satisfactory tick-over
is obtained, but take care that the achievement of
too slow a tick-over - that is, slower than is
actually necessary-does not lead to a "spot"
which may cause stalling when the throttle is
very slightly open.
(iii) Throttle Cut-away. Having set the pilot
adjuster, open up the throttle progressively and
note positions where, if at all, the exhaust note
becomes irregular. If this is noticed, leave the
throttle open at this position and close the air
lever slightly; this will indicate whether the spot
is rich or weak. If it is a rich spot, fit a throttle
valve
Section F3 Page 4
Amal Monobloc Carburetter
The supply of air to the engine is controlled by a
throttle slide which carries a taper needle operating
in the needle jet. The needle is secured to the
throttle slide by a spring clip fitting in one of five
grooves and the mixture strength throughout a large
proportion of the throttle range is controlled by the
position of this needle in the slide and by the size of
the jet in which it works. There is, however, a
restricting or main jet at the bottom of the needle jet
and the size of this controls the mixture strength at
the largest throttle openings. At very small throttle
openings petrol and air are fed to the engine
through a separate pilot system, which has an outlet
at the engine side of the throttle. The air supply to
this pilot system is controlled by the pilot air screw
and the slow running of the engine can be adjusted
by means of this screw and a stop which holds the
throttle open a very small amount. The throttle slide
is cut away at the back and the shape of this
cut-away controls the mixture at throttle openings
slightly wider than that required for slow running.
There is a compensating system to prevent undue
enriching of the mixture with increasing engine
speed, this system consisting of a primary choke
surrounding the upper end of the needle jet through
which air is drawn in increasing quantities as the
depression in the main choke increases. This air
supply and the supply to the pilot system are taken
from two separate ducts in the main air intake to the
carburetter so that all the air passing to the engine
can be filtered by fitting an air cleaner to the main
carburetter air intake.
Two small cross holes in the needle jet, at a level
just below the static level in the float chamber,
permit petrol to flow into the primary choke when
the engine is not running or when it is running at
very low speeds, thus forming a well of petrol
which will be drawn into the engine on starting or
accelerating from low speeds. At moderately high
engine speeds the level of petrol in the float
chamber falls slightly and in consequence no more
fuel flows through the cross holes in the needle jet
so that the petrol well remains empty until the
engine slows down or stops.
A handlebar controlled air slide is provided to
enrich the mixture temporarily when required.
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1. General Description
The Amal Monobloc Carburetter has been
introduced as an improvement on the earlier
standard needle type. In general it gives better
petrol consumption, combined with improved
starting and acceleration from low speeds and a
small increase in maximum speed.
The float chamber is integral with the mixing
chamber and contains a pivoted barrel-shaped
float operating on a nylon fuel needle. There is a
considerable leverage ratio between the float and
the needle and, in consequence, flooding is rare
unless there is dirt on the needle seating.
2. Tuning the Carburetter(s)
The throttle opening at which each tuning point
is most effective is shown in Fig. 2. It should be
remembered, however, that a change of setting at
Section F4 Page 1
then undesirably fast it can be slowed down by
unscrewing the throttle stop a fraction of a turn.
It will be noted that of the four points at which
adjustments are normally made, i.e., pilot air
screw, throttle cut-away, needle position and main
jet size, the first and third do not require changing
of any parts of the carburetter. Assuming that the
carburetter has the standard setting to suit the
particular type of engine any small adjustments
occasioned by atmospheric conditions, changes in
quality of fuel, etc., can usually be covered by
adjustment of the pilot air screw and raising or
lowering the taper needle one notch. If, however,
the machine is used at very high altitudes or with a
very restricted air cleaner a smaller main jet will be
necessary. The following table gives the reduction
in main jet size required at different altitudes:
Altitude, ft.
Reduction, %
3,000
5
6,000
9
9,000
13
12,000
17
In the case of carburetters for engine running
on alcohol fuel considerably larger jets are
needed. In most cases a No. 113 needle jet will be
required and the main jet size will require to be
increased by an amount varying from 50% to
150% according to the grade of fuel used.
If the engine is run on fuel containing a small
proportion of alcohol added to the petrol, a rough
and ready guide is that the main jet should be
increased by 1 % for every 1 % of alcohol in the
fuel. In most cases alcohol blends available from
petrol pumps do not contain sufficient alcohol to
require any alteration to the carburetter setting.
The range of adjustment of the taper needle
and the pilot air screw are determined by the size
of the needle jet and of the pilot outlet
respectively. Standard needle jets have a bore at
the smallest point of .1065 in. and are marked
106. Alternative needle jets .1055 in., .1075 in.,
.109 in. and .113 in. bore are available and are
marked 105, 107, 109 and 113 respectively.
The standard pilot outlet bore is .025 in. but in
some cases larger size pilot outlets are used. Since
the pilot outlet is actually drilled in the body of
the carburetter it is necessary to have a
carburetter with the correct size pilot outlet if the
best results are to be obtained.
The accompanying table shows the standard
settings for Amal Monobloc Carburetters used on
Royal Enfield motor cycles.
Both instruments used for the twin carburetter
models are identical in all respects but for the float
chamber arrangement, which is as follows:
The carburetter which supplies the left-hand
cylinder has an integral float chamber which
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Section F4 Page 2
s.
Third-the throttle valve should be selected with
the largest amount of cut-away which will prevent
spitting or misfiring when opening the throttle
slowly from the idling position.
Fourth-The lowest position of the taper needle
should be found consistent with good acceleration
with the air slide wide open.
Fifth-The pilot air screw should be checked to
improve the idling if possible. When setting the
adjustment of the pilot air screw this should be
done in conjunction with the throttle stop. Note
that the correct setting of the air screw is the one
which gives the fastest idling speed for a given
position of the throttle stop. If the idling speed is
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any point will have some effect on the setting
required at other points; for instance, a change of
main jet will have some effect on the mixture
strength at half throttle which, however, is mainly
controlled by the needle position. Similarly an
alteration to the throttle cut-away may affect both
the needle position required and the adjustment of
the pilot air screw. For this reason it is necessary to
tune the carburetter in a definite sequence, which
is as follows:
First-Main Jet. The size should be chosen
which gives maximum speed at full throttle with
the air control wide open. If two different sizes of
jet give the same speed the larger should be
chosen for safety as it is dangerous to run with too
weak a mixture at full throttle.
Second-The pilot air screw should be set to give
good idling. Note that the pilot jet is detachable
and two sizes are available, 25 c.c. and 30 c.c. If
the pilot air adjusting screw requires to be screwed
out less than half a turn the larger size pilot jet
should be used; if the air screw requires to be
screwed out more than 2-3 turns fit the smaller
size of pilot jet.
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Section F4 Page 3
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also controls the fuel supply via a connecting pipe
to the right-hand instrument which does not have
a float chamber in unit with it.
It is important that the pilot air screws of both
carburetters are in identical positions, relative to
one another, the same applying to the throttle
valves when seated on their stops. This is essential
for an even smooth tickover and low-speed
running. The speed of the tickover is regulated by
these four adjuster screws. For an instant pick-up,
both throttle valves must commence to rise from
their stops simultaneously, when the twist grip is
rotated. This is obtained by adjusting the twin
control cables. Each main jet needle must be in
the third groove.
Both air slides, operated from a single
handlebar lever, must open and close identically,
as failure to do this may result in one slide not
opening fully, with a resultant loss of power.
It is most important that all of these
adjustments are carried out in a thorough and
careful manner if the maximum power and
smoothness is to be obtained.
The "ears" to be found on the leading edges of
the battery and toolbox lids are to shield the
carburetter air intakes and so prevent misfiring at
maximum revs.
4. Causes of High Petrol Consumption
If the petrol consumption is excessive first
look for leaks either from the carburetter, petrol
pipe, petrol tap(s) or tank. If coloured petrol is in
use this will readily indicate the presence of any
small leaks which otherwise might pass unnoticed.
If the petrol system is free from leaks, carefully set
the pilot adjusting screw as described in
Subsection 2 to give the correct mixture when
idling. Running with the pilot adjusting screw too
far in is a common cause of excessive petrol
consumption. If the consumption is still heavy try
the effect of lowering the taper needle in the
throttle slide by one notch. Do not fit a smaller
main jet as this will not affect consumption except
when driving on nearly full throttle and may make
the mixture too weak at large throttle openings,
thus causing overheating. Remember that faults in
other parts of the machine can have a marked
effect on petrol consumption. Examples of this
are binding brakes, chains too tight or out of line
and, in particular, under-inflated tyres.
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3. Dismantling Carburetter
The construction of the carburetter is clearly
shown in Fig. 3.
If the float chamber floods, first make sure
that there is no dirt on the fuel needle seating.
Owing to the use of a nylon needle and the
leverage ratio between float and needle, flooding
is very unlikely with this type of carburetter unless
dirt is present or, of course, the float is punctured.
If it is necessary to remove the jet block note
that this is withdrawn from the upper end of the
mixing chamber after unscrewing the jet holder.
Be careful not to damage the jet block when removing or refitting it. Note that the large
diameter of the jet block pulls down on to a thin
washer.
A single strand of an inner control cable is
useful for clearing the small passages in the jet
block and care must be taken not to enlarge these
by forcing the wire through them. Compressed air
from a pipe line or a tyre pump is preferable. A
choked main jet should be cleared only by
blowing through it.
Section F4 Page 4
Setting of Amal Monobloc carburetters on Royal Enfield Motorcycles
Choke
Bore
inches
Main Jet
Needle
Jet
Needle
Position
Throttle
Valve
Pilot Jet
250 Clipper
1955 (late) 1958 (early)
375/10
25/32
120
105
3
4
25
250 Crusader
1957 - 1962
250 Clipper
late 1958 on
375/16
7/8.
120
105
3
3.1/2
25
376/216
15/16
150
106
3
3.1/2
25
1.1/16
180
106
4
3.1/2
25
270
106
3
3.1/2
25
3
3.1/2
25
4
30
3.1/2
25
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Machine
Carburetter
Type
Number
Super 5
1962 on and
Continental (all)
376/283
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389/217
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Continental GT
1965 on
350 Bullet
1955 (late) 1958 350 Clipper
1958 - 1962
Works Replica
1958 - 1961
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Crusader Sports
1959 onwards
and 250 Trials
1962 on
1
180
106
350 Bullet
1959 - 1962
376/215
1.1/16
190
350 Bullet
1963 on
376/297
1.1/16
180
106
500 Bullet
1956 - 1958
389/9
1.1/8
200
106
106
3
3.1/2
30
or
376/29
106
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3.1/2
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500 Bullet
1959 - 1961
389/34
1.3/16
(250 if no
air filter)
Meteor Minor
1958 - 1963
376/92
1.1/16
250
106
2
3.1/2
30
Super Meteor
1956 - 1962
Constellation
1963
376/41
1.1/16
240
106
3
3.1/2
30
Constellation
1960 - 1962
LH 376/242
RH 376/243
1.1/16
320
106
3
4
25
Section F4 Page 5
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SECTION G1D
Lucas Rotating Magnet Magneto Model SR2
Used on 1956-59 Super Meter
(i) After every 150 running hours (say 5,000
miles) remove the moulded cover and add a
FEW drops of thin machine oil to the visible
end of the contact breaker pivot post.
(ii) After 1,000 running hours (say 30,000
miles) remove the moulded cover and withdraw
the rotating electrode. Slacken the fixed-contact
plate securing screws and pivot the assembly to
the fullest extent of the adjusting slots. Slacken
the nut securing the end of the contact breaker
spring and lift off the moving-contact assembly.
Smear the pivot pin with a small quantity of
Mobilgrease No. 2 or its equivalent. Replace the
components in the reverse order of dismantling.
(iii) The magneto rotor is mounted on ball
bearings. These bearings are packed with high
melting point grease before leaving the factory
and require no attention for a considerable time.
About every two years, or when the engine is
undergoing a general overhaul; the magneto
should be dismantled by a Lucas Service Depot
or Agent and the bearings repacked with high
melting point GREASE
(b) Cleaning
(i) Occasionally remove the moulded cover
and wipe the inside of the cover with a soft dry
cloth.
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1. General
The magneto rotor comprises a permanent
magnet fitted with two laminated pole shoes.
The stator consists of laminated pole pieces
bridged by a laminated coil core. The coil has
concentrically wound primary and secondary
windings.
The rotor is driven by the engine through an
automatic advance coupling and induces an
alternating magnetic field in the laminated iron
core of the coil. This field in turn induces
alternating voltages in the primary and
secondary windings of the coil. Magnetic flux
due to current flowing in the primary winding
tends to oppose any change in direction of the
magnetic field in the laminated iron core. In this
way, field reversals due to the rotating magnet
are delayed until the contact breaker opens. This
removes the restraining influence of the primary
winding and the consequent rapid reversal of the
magnetic flux linked with the coil causes a high
voltage to be induced in the secondary winding.
The body of the magneto is formed of a
single casting enclosed at the contact breaker
end by a moulded cover. The cover is designed
with the high tension cable outlets in a
downward direction, thus preventing the
retention of moisture at the terminal
connections. The coil and capacitor are robustly
constructed and specially treated to withstand
very arduous conditions.
The automatic timing control is a
centrifugally operated mechanism enabling an
angular movement of the magneto rotor to occur
relative to the drive. The mechanism consists of
two members flexibly coupled by pivoted
spring-loaded governor weights and toggles. At
low engine speeds and during starting, the
weights are closed and a delayed spark is
produced. As the engine speed increases, the
governor weights swing out and advance the
rotor (and thus the cam and the spark) relative
to the drive.
2. Routine Maintenance
(a) Lubrication
TAKE GREAT CARE TO PREVENT
OIL OR GREASE GETTING ON OR NEAR
THE CONTACTS.
Section G1d Page 1
MAGNETO MODEL SR2 WITH COVER REMOVED
Fig. 2
(i) Remove the sparking plugs from the
engine. Hold the end of each high tension cable
about 1/8 in. from the cylinder block and operate
the kickstarter. If strong and regular sparking is
produced the sparking plugs should be cleaned
and adjusted.
(ii) If no sparking is produced, examine the
high tension cable and if necessary renew it as
described in Sub-section 2(d).
(iii) Disconnect the cable to the cut-out
switch at the magneto and re-test. If the magneto
now functions normally the defect is in either
the cable or the cut-out switch. Correct by
replacement.
NOTE.-In no circumstances must the contact
breaker cam be removed from or turned on the
spindle. The cam is correctly positioned when
the magneto is built and the performance of the
instrument depends on this position being
maintained.
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Section G1d Page 2
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3. Servicing
To locate cause of misfiring or failure of
ignition, check as follows:-
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Clean the electrodes, the spaces between the
electrodes and see that the carbon brush is clean
and moves freely in its holder. Clean the outside
of the cover before replacing it.
(ii) Examine the contact breaker. If the
contacts are burnt or dirty, clean them by
polishing with a very fine carborundum stone or
fine emery cloth. The contacts may be cleaned
more easily if the moving contact assembly is
removed, as Sub-section 2 (a) (ii).
(c) Adjusting Contact Breaker
After cleaning check the gap between the
contacts. Turn the engine until the contacts show
the maximum opening which should measure
0.010 in. to 0.012 in. If the setting is incorrect,
slacken the two screws securing the
fixed-contact plate and move the plate until the
correct gap is obtained. Tighten the securing
screws and measure the gap again. Check the
gap for the other position of the engine giving
maximum opening of the contacts. Refit the
distributor gear so that the marked teeth of the
gear and of the drive engage, retighten the gear
retaining screw.
During the first 20 hours running of a new
magneto or replacement contact set, most of the
bedding down of the contact breaker heel occurs.
The contact breaker gap should, therefore, be
checked and, if necessary, reset as described
above.
(d) Replacement of High Tension Cables
Use 7 mm. P.V.C. or neoprene-covered
rubber insulated ignition cable for the high
tension leads. When connecting a new cable to
the magneto do not bare the cable but cut it off
flush to the required length. Remove the
moulded cover, slacken the cable retaining screw
and pull out the old cable. Push the new cable
fully home and secure by tightening the screw.
The pointed end of this will pierce the insulation,
make contact with the cable core and lock the
cable in place. After fitting a high tension cable a
continuity test should be made between the
cover electrode and plug end of the cable.
4. Automatic Advance Mechanism
This is automatically lubricated and requires
no attention beyond making sure that it operates
freely and the springs are securely fastened. For
timing instructions see Section C4, Subsection
4.
HOW TO LOCATE AND REMEDY TROUBLE
Condition
ENGINE WILL NOT
START.
Possible Causes
Controls not set correctly for starting.
Contact breaker inoperative.
Contacts need cleaning and adjusting.
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Plugs not sparking.
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Defect in cut-out circuit.
Incorrect timing.
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ENGINE MISFIRES.
Defective fuel supply.
Sparking plugs need cleaning and
adjusting.
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Contacts need cleaning and adjusting.
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Defective high tension supply.
Method of Detection and Remedy
See that the ignition is switched on, petrol turned
on and everything is in order for starting.
Crank the engine and check that the contact
breaker opens and closes correctly.
Clean and adjust the contact breaker as described
above.
Detach the high tension cables from the plugs.
Hold the cables 1/8” (3.17 mm.) from the engine
and see if a spark jumps the gap when the engine
is cranked.
(i) If a spark is produced, check the plugs by
substitution.
(ii) If no spark is produced, check the cables by
substitution. Clean and check inside of cable
cover.
Disconnect the remote cut-out switch and crank
the engine. If the engine now starts, renew the
connecting cable or switch.
Check the magneto-to-engine timing. (See Section C4).
Inspect the carburetter, petrol supply, etc.
Remove plugs from engine. Clean off soot or
carbon and check plug "points" for correct gap
width (.018 in.).
Clean and adjust the contact breaker.
Check high tension cables by substitution.
Clean and check inside of cable cover.
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If, after making the above checks, a fault in the magneto is suspected but cannot be located, the nearest Lucas
Service Depot or Agent should be consulted. When communicating with a Service Depot, it is necessary, in
addition to describing the trouble, and the type and year of engine, to state the Model, Type and Service Number
of the magneto.
Section G1d Page 3
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SECTION G1f
Lucas Twin-Cylinder Magneto
Models K2F (42369) and K2F (42369B)
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1. General
This magneto incorporates a wound rotating
armature and a high-energy permanent magnet
field system, this latter being cast integral with
the body. The unit is designed for 3-point flange
fixing.
Small breathing holes are provided in the
body of the magneto. These holes should not be
allowed to become blocked.
Provision is made for altering the ignition
timing by the manual control method, in which
the cam ring is moved relatively to the armature.
The lever controlling this movement is mounted
conveniently on the handlebars and is connected
by a control cable to the magneto.
2. Routine Maintenance
2 (a). Lubrication
To be carried out every 3,000 miles.
(i) Wipe out the outside of the magneto to
remove dirt or grease, and then take off the
contact
breaker
cover.
Unscrew
the
hexagon-headed screw in the centre of the
contact breaker and withdraw the contact
breaker from its housing. Push aside the contact
breaker arm retaining spring of the K2F (42369)
type unit, and in the case of the later K2F
(42369B) model, prise off the special locking
plate from the contact breaker arm pivot pin,
taking care not to lose the insulating washer
beneath it.
Slacken the screw which retains the contact
breaker arm spring. The contact breaker arm
may then be lifted from its pivot.
Wipe away any dirt or grease from the
contact with a petrol-moistened cloth. If
necessary, use a very fine carborundum stone to
polish the contact, re-cleaning afterwards with a
petrol-moistened cloth. Smear the pivot pin with
a little Mobilgrease No. 2 before refitting the
contact breaker arm.
Remove the cam ring, which is a sliding fit in
its housing, and lightly smear inside and outside
surfaces with Mobilgrease No. 2. Both removal
and refitting of the cam can be made easier if the
handlebar control lever is half retarded, thus
taking the cam away from its stop pin. Apply
one or two drops of thin machine oil to the felt
cam lubricator in the housing. Refit the cam,
taking care that the stop peg in the housing and
the plunger of the manual timing control engage
with their respective slots.
Refit the contact breaker. This can be made
easier if the contact breaker heel is away from
the cam lobe; turn the engine until this is so. The
key on the projecting part of the contact breaker
base must engage with the keyway in the
armature shaft. Refit the hexagon-headed screw
and tighten with care. It must not be slack, nor
must undue force be used.
(ii) Bearings. The main bearings of the
magneto are packed with grease during
manufacture and need no attention until a
general overhaul is undertaken.
Section G1f Page 1
To do this, slip back the rubber shroud and,
by means of the hexagon at the base, unscrew
the control barrel. If the cable and the plunger to
which it is attached are now pulled upwards, the
cable nipple can be disengaged from the plunger
slot.
Soften the solder and remove the nipple.
Thread the new length of cable through the
rubber shroud, cable adjuster, control barrel,
sealing washer and restoring spring. Solder the
nipple to the end of the cable. Engage the nipple
with the slot in the plunger and screw the
control barrel into the body, ensuring that the
sealing washer is correctly fitted between the
barrel and the body. Take up any slackness in
the cable by means of the adjuster before
refitting the rubber shroud in position.
2 (f). Contact Breaker Springs
Correct contact breaker spring pressure
measured at the contacts is 18-24 oz.
3. Servicing
3 (a). Testing Magneto in Position on Engine
To locate cause of misfiring or failure of
ignition, check as follows
(i) Remove the sparking plugs from the
engine. Hold the end of the H.T. cable about 1/8
in. from the cylinder block and crank the engine.
If strong and regular sparking is produced the
fault lies with the sparking plug or plugs which
must be cleaned and adjusted or renewed.
(ii) If no sparking is produced, examine the
H.T. cable and, if necessary, renew it as
described above in Subsection 2 (d).
(iii) Very occasionally, the fault may be due
to a cracked or punctured pick-up moulding.
This type of fault is not easily detected by
inspection, and a check should therefore be
made-by substitution.
(iv) If the ignition cut out switch is
suspected, disconnect the cable at the magneto
and retest. If the magneto now functions
normally, the fault is in either the cable or the
cut out switch. Correct by replacement.
(v) If the magneto has recently been replaced
or removed, it may be incorrectly timed. Refer
to the engine makers' instructions, and check.
(vi) Check the contact breaker for cleanliness
and correct contact setting as described under
Maintenance.
If the cause of faulty operation cannot be
traced from the foregoing checks, the cause may
be an internal defect in the magneto. The
magneto should therefore be removed from the
engine for dismantling.
Further ignition particulars are given in a
booklet issued by the makers, a copy of which
we shall be pleased to forward upon request.
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Section G1f Page 2
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2 (b). Adjustments
Check every 3,000 miles.
(i) Setting contact breaker gap. The contact
breaker gap must be set to 0.012-0.015 in. when
the contacts are fully separated.
To adjust the gap, turn the engine until the
contacts are fully opened. On K2F (42369) type
magnetos the locking nut of the adjustable
contact must first be slackened. Turn the contact
by its hexagon head until a feeler gauge of
appropriate thickness is a sliding fit in the gap.
Tighten the locknut and recheck the gap. On
K2F (42369B) type magnetos the cheese-headed
screw which locates the spring anchor plate is
slackened; the plate on which the contact is
mounted may then be moved away from or
towards the contact breaker arm, to give the
required clearance.
(ii) Adjusting the Timing Control Cable.
Slackness in the manual control timing can be
taken up by sliding the waterproofing rubber
shroud up the cable and turning the
hexagon-headed cable adjuster. After adjusting,
return the rubber shroud to its original position
over the adjuster and control barrel.
2 (c). Cleaning
To be carried out every 6,000 miles.
Check the contact breaker contacts and, if
necessary, clean them as described in Subsection
2(a). Wipe the outside of the magneto to remove
dirt or grease. Check the cable adjuster and
control barrel for signs of water ingress.
Remove the high tension pick-ups and polish
with a soft dry cloth. Each carbon brush must
move freely in its holder and, if necessary, clean
it with a petrol-moistened cloth. Should a brush
be worn to within 1/8 in. of the shoulder it must
be renewed.
Whilst the pick-up moulding is removed,
clean the slip ring track and flanges by holding a
soft dry cloth against them with a suitably
shaped piece of wood while the engine is slowly
turned.
The high tension cables must be kept clean
and dry.
2 (d). Renewing High Tension Cables
If, on inspection, the high tension cable
shows signs of deterioration, it must be
replaced, using 7mm. rubber, P.V.C. or
neoprene covered ignition cable. To fit a new
high tension cable, bare the end for about 3/8 in.,
thread the knurled moulded nut over the cable,
and thread the bared cable through the washer
removed from the old cable.
Bend back the strands radially, and screw the
nut into the pick-up moulding.
2 (e). Renewing Timing Control Cable
The timing control cable should be renewed
if it becomes frayed, otherwise moisture may
enter the contact breaker housing.
SECTION G2h
Generator/Rectifier Charging Set
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to see that the connections are clean and tight.
The nuts that clamp the rectifier plates together
must never under any circumstances be
slackened, as the clamping pressure has been
carefully adjusted during manufacture to obtain
the correct performance characteristics. A
separate nut is used for securing the unit to the
machine and this nut should be checked
occasionally to see that it is tight.
RECTIFIER
Fig. 2
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1. General
(a) Constructional Notes
The alternator consists of a spigot mounted
6-coil laminated iron stator with a rotor carried
on and driven by an extension of the crankshaft.
The rotor has a hexagonal steel core, each face
of which carries a high energy permanent
magnet keyed to a laminated pole tip. The pole
tips are riveted circumferentially to brass side
plates, the assembly being cast in aluminium and
machined to give a smooth external finish.
As shown in Figure 1, there are no rotating
windings, commutator, brushgear, bearings or
oil seals and consequently the alternator requires
no maintenance apart from an occasional check
of the three-way connector in the three output
cables to see that this is clean and tight.
If removal of the rotor becomes necessary
for any purpose, there will be no necessity to fit
keepers to the rotor poles. When the rotor is
removed, wipe off any metal swarf that may
have been attracted to the pole tips and put the
rotor in a clean place.
STATOR AND ROTOR OF ALTERNATOR RM15
Fig. 1
(b) Rectifier
A bridge-connected rectifier is fitted to
convert the alternator output to a uni-directional
battery charging current. The rectifier requires
no maintenance apart from an occasional check
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(c) Operation
The alternator stator is wound with three
pairs of series-connected coils, one pair being
permanently connected across the rectifier. The
purpose of this latter pair is to provide a small
trickle charging current for the battery whenever
the engine is running.
Connections to the remaining coils vary
according to the demand on the battery and, as
shown schematically in Figure 3, depend on the
positions of the lighting switch. When no lights
are in use, the coils are short-circuited and the
alternator output is regulated to its minimum
value by interaction of the rotor flux with the
flux set up by the current flowing in the shorted
coils. In the "Pilot" or parking lights position,
the shorting link is disconnected and, the
regulating fluxes being consequently reduced,
the alternator output increases and compensates
Section G2h Page 1
for the parking lights load. In the "Head"
position of the lighting switch, the output is
further increased by all three pairs of coils
being connected in parallel.
Fig. 3
WIRING DIAGRAM
Fig. 4
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CIRCUIT DIAGRAMS FOR POSITIONS OF
LIGHTING SWITCH
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© LIGHTING SWITCH AT “HEAD”
INTERNAL CONNECTIONS OF ALTERNATOR
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2. Maintenance
(a) Check wiring occasionally to see that
all connections are clean and tight.
(b) Check tightness of rectifier securing
nut.
Section G2h Page 2
SECTION G2j
Lucas A.C. Lighting-Ignition System
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permanent magnet keyed to a laminated pole tip.
The pole tips are riveted circumferentially to
brass side plates, the assembly being cast in
aluminium and machined to give a smooth
external finish. The stator and rotor can be
separated without the need to fit magnetic
keepers to the rotor poles.
As the rotor turns, rapid and repeated
reversals of flux take place in the coil cores.
These lines cut through the turns of the coil and
induce alternating voltages in that coil. External
connections are taken to these coils from a
bridge connected rectifier (see Fig. 2).
3. Circuit Detail
The alternator stator carries three pairs of
series connected coils, one pair being
permanently connected across the rectifier bridge
network. The purpose of this latter pair is to
provide some degree of charging current for the
battery whenever the engine is running.
2. Alternator Models RM14 and RM15
Early models are fitted with type RM14
alternator, which has an outside diameter of 5.7/8
in. Later models are fitted with type RM15 (see
Fig. 1) with an outside diameter of 5 in. They
give a high output at low r.p.m. The alternator
comprises two main components, a stator and a
rotor. The stator is built up from iron laminations
and carries three pairs of series-connected coils
insulated from the laminations. The rotor has a
hexagonal steel core, each face of which carries a
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STATOR AND ROTOR OF ALTERNATOR RM15
Fig. 1
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1. General
The Lucas A.C. Lighting-Ignition System
comprises seven main components
(1) Alternator with magnet rotor.
(2) Bridge-connected rectifier.
(3) Ignition coil.
(4) Distributor with automatic timing control.
(5) Lighting switch.
(6) Ignition switch.
(7) 6-volt battery (see Section G4a).
Under normal running conditions, electrical
energy in the form of rectified A.C. passes
through the battery from the alternator, the rate
of charge depending on the position of the
lighting switch. When no lights are in use, the
alternator output is sufficient only to trickle
charge the battery. When the lighting switch is
turned to the "Pilot" or "Head" positions the
current increases proportionately.
GENERAL VIEW OF RECTIFIER
Fig. 2
Connections to the remaining coils vary
according to the position of the lighting and
ignition switch controls, as shown schematically
in Fig. 3.
When no lights are in use the alternator
output is regulated to its minimum value by
interaction of the rotor flux and the flux set up
by current flowing in the short-circuited coils.
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To ensure easy starting in the "EMG" position
of the switch, the stator and rotor poles of the
A.C. generator must be correctly positioned. This
is ensured by: (a) fitting the rotor sleeve so that
the keyway is at the top when the engine is at
T.D.C.; (b) seeing that the key is correctly fitted;
(c) fitting the stator so that the leads enter it at
the top, at the back of the stator, and (d) timing
the contact breaker correctly, i.e., so that the
points are just about open when the pistons are
1/32 in. before T.D.C.
After starting on the "EMG" position, the
switch should be returned to the "IGN" position.
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CIRCUIT DIAGRAMS FOR POSITIONS OF
LIGHTING SWITCH
Fig. 3
EMERGENCY STARTING CIRCUIT
Fig. 4
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6. Routine Maintenance
The alternator and rectifier require no
maintenance apart from ensuring that all
connections are clean and tight.
If the rotor, stator, engine crankshaft or rear
half of the chaincase have been disturbed, the air
gap between the rotor and stator should be
checked. If a feeler gauge of at least .008 in.
thick cannot be passed between the rotor and
each of the stator poles the alignment should be
checked.
The nuts which clamp together the rectifier
plate assembly must not under any
circumstances be slackened. They have been
carefully set during manufacture to give correct
rectifier performance. A separate nut is used to
secure the rectifier to the frame of the
motorcycle.
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4. Emergency Starting
An emergency starting position is provided
on the ignition switch. This is for use if the
battery has become discharged and a normal start
cannot be made. In the switch position "EMG"
four coils of the alternator are connected through
one arm of the rectifier to the primary winding of
the ignition coil, with the contact breaker in
series.
This system, which on a single cylinder
machine could cause trouble through unwanted
sparks on the compression stroke of the engine,
does not do so on the twin, owing to the fact that
the distributor permits the passage of a spark
only when the engine is near the firing position.
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In the "Pilot" position these coils are
disconnected and the regulating fluxes are
consequently reduced. The alternator output
therefore increases and compensates for the
additional parking light load.
In the “Head” position the alternator output is
further increased by connecting all three pairs of
coils in parallel.
5. Direct Operation
Short journeys without the battery can be
made with the switch in the "EMG" position. To
do this, the cable normally connected to the
battery negative terminal must be connected to
an earthed point on the machine. If lights are
required when the battery is disconnected, use
only the headlights and keep the engine speed
low to prevent excessive voltage rise.
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DISTRIBUTOR MODEL DKX2A (early models)
Fig. 5
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7. Ignition Coil Model Q6 or MA6
The ignition coil should be kept clean and the
terminals kept tight.
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8. Distributor
Early Models: Type DKX2A.
Later Models: Type Lucas 18D2.
Lubrication every 3,000 miles. No grease or
oil must be allowed to get on or near the
contacts when carrying out the following
procedure.
Smear the surface of the cam very lightly
with Ragosine Molybdenised non-creep oil or
clean engine oil.
Place a spot of Ragosine oil or clean engine
oil on the contact breaker pivot.
Automatic Timing Control. To obtain
access to this lift off the rotor arm and unscrew
the two screws securing the contact breaker base
plate to the distributor. Lubricate the automatic
timing control, thus exposed, with Ragosine
Molybdenised non-creep oil, or clean engine oil,
paying particular attention to the pivots. Refit the
base plate and rotor arm.
Cleaning every 6,000 miles. Remove and
clean the cover paying particular attention to the
spaces between the metal electrodes and check
that the small carbon brush moves freely in its
holder.
Examine the contact breaker, the contacts
must be free from grease or oil. If they are burnt
or blackened, clean with fine carborundum stone
or very fine emery cloth, afterwards wiping
away any trace of dirt or metal dust with a clean
petrol-moistened cloth. Cleaning of the contacts
is made easier if the lever carrying the moving
contact is removed.
Contact Breaker Setting. The contact
breaker setting should be checked after the first
500 miles running and subsequently every 6,000
miles. To check the gap, turn the engine over
slowly until the contacts are seen to be fully
open and insert a 0.014-0.016 in. feeler gauge
between the contacts.
If the gap width is correct the gauge will be a
sliding fit. To adjust the setting, set the engine in
the position giving maximum contact opening
and slacken the two screws securing the fixed
contact plate. Adjust the position of the plate
until the gap is the thickness of the gauge and
tighten the two screws.
9. Renewing High Tension Cables
If any of the high tension cables show signs
of perishing or cracking they must be replaced,
using 7mm. Neoprene covered rubber ignition
cable. To connect the cable to the distributor or
to ignition coil model Q6, remove the metal
washer
and moulded terminal nut from the defective
cable. Thread the new cable through the moulded
terminal nut and cut back the insulation for about
¼ in. Pass the exposed strands through the metal
washer and bend them back radially. Screw the
terminal into the pick-up moulding.
To connect the cable to ignition coil model
MA6, pass the cable through the rubber
grommet, push the metal clip into the end of the
cable (which should be cut off square), insert the
cable and clip into the socket in the end of the
coil, and slide the grommet into place to exclude
water.
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Battery Model PUZ7E
Heat is produced by the mixture of acid and
water, the electrolyte should be allowed to cool
before pouring it into the battery.
The specific gravity of the electrolyte varies
with the temperature. For convenience in
comparing specific gravities, they are always
corrected to 60° F., which is adopted as a
reference temperature.
The method of correction is as follows :
For every 5°F. below 60°F., deduct .002 from
the observed reading to obtain the true specific
gravity at 60°F. For every 5°F. above 60°F. add
.002 to the observed reading to obtain the true
specific gravity at 60°F.
The temperature must be that indicated by a
thermometer having its bulb actually immersed in
the electrolyte and not the ambient temperature.
Fill the cells to the tops of the separators, in one
operation. The battery filled in this way is 90%
charged. When time permits, a short freshening
charge for no more than four hours at the normal
recharge rate of 1.5 amp. should be made.
2. Preparation for Service
The electrolyte is prepared by mixing together
distilled water and concentrated sulphuric acid,
using lead-lined tanks or suitable glass or
earthenware vessels. Slowly add the acid to the
water, stirring with a glass rod. Never add water to
the acid, as this causes dangerous spurting of the
concentrated acid. The specific gravity of the
filling electrolyte depends on the climate in which
the battery is to be used.
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1. General
The model PUZ7E (see Fig. 1) is a
"drycharged" battery and is supplied without
electrolyte but with its plates in a charged
condition. When the battery is required for service
it is only necessary to fill each cell with sulphuric
acid of the correct specific gravity. No initial
charging is required, but the battery must be left to
stand at least one hour after filling before putting
the machine into service and then adjusting the
acid level if necessary.
3. Routine Maintenance
Fortnightly (or more frequently in hot
climates) examine the level of electrolyte in the
cells and if necessary add distilled water to bring
the level up to the tops of the separators. The use
of a Lucas Battery Filler will be found helpful, as
it ensures that the correct electrolyte level is
automatically maintained and also prevents
distilled water from being spilled on the top of the
battery (see Fig. 2).
Occasionally examine the terminals, clean and
coat them with petroleum jelly. Wipe away all
Section G4a Page 1
The following table shows the state of charge
at different values of specific gravities
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dirt and moisture from the top of the battery and
ensure that the connections are clean and tight.
4. Servicing
If the battery is subjected to long periods of
night parking with the lights on, without suitable
opportunities for recharging, a low state of charge
is to be expected.
Measure the specific gravity of the acid of each
cell in turn with a hydrometer (see Fig. 3).
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If the battery is discharged, it must be
recharged, either on the motor cycle by a period
of daytime running or from an external D.C.
supply at the normal recharge rate of 1.5 amp.
Section G4a Page 2
SECTION G5d
Head and Tail Lamps
3. Replacing the Light Unit and Bulb
Slacken the securing screw at the top of the
headlamp rim. Remove the front rim and Light
Unit assembly.
Withdraw the adaptor from the Light Unit by
twisting it in an anti-clockwise direction and
pulling it off. Remove the bulb from its locating
sleeve at the rear of the reflector.
Disengage the Light Unit securing springs
from the rim and lift out the Light Unit.
Position the new unit in the rim so that the
word "TOP" on the lens is correctly located when
the assembly is mounted on the headlamp. Refit
the securing springs ensuring that they are equally
spaced around the rim.
Replace the bulb and adaptor. The bulb must
be the Lucas "prefocus" type-6 v. 30/24 watt
Lucas No. 312.
Locate the bottom of the Light Unit and front
rim assembly in the headlamp shell or in the fixing
rim attached to the Casquette fork head. Press the
front on and tighten the securing screw at the top
of the headlamp.
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1. Headlamp
In all models the headlamp incorporates the
Lucas Light Unit MCF 700 built into the
Casquette fork head which also contains twin
parking lamps as well as the ammeter and
headlight switch.
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2. Lucas Light Unit
The unit incorporates a combined reflector
and front lens assembly (see Fig. 1). This
construction ensures that the reflector and lenses
are permanently protected, thus the unit keeps its
high efficiency over a long period. A
"prefocus"bulb is used, the filaments of which
are accurately positioned with respect to the
reflector, thus no focusing device is necessary.
The bulb has a large cap and a flange, which
has been accurately positioned with relation to
the bulb filaments during manufacture. A slot in
the flange engages with a projection on the inside
of the bulb holder positioned at the back of the
reflector.
A bayonet-fitting adaptor with spring-loaded
contacts secures the bulb firmly in position and
carries the supply to the bulb contacts.
The outer surface of the lens is smooth to
facilitate cleaning. The inner surface is formed
of a series of lenses which determine the spread
and pattern of the light beams.
In the event of damage to either the lens or
the reflector a replacement light unit must be
fitted.
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4. Parking Lights
Access to the parking bulbs is obtained by
removing the parking lamp rim (see Fig. 2). This is
forced over the edge of the rubber lamp body and
is additionally secured by means of a small fixing
Section G5d Page 1
screw. After removal of the lamp rim the parking
lamp lens can be pulled out of the rubber body,
after which the bulb will be accessible.
from excessive heat affecting the plastic cover. At
the same time, the 6 watt filament, if used as a
stop-tail light, will be ineffective in bright sunlight
or at night when the tail light filament is
illuminated.
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5. Tail Light
The Lucas lamp, Type 564 (Fig. 3) is a
combined stop and tail light and also incorporates
a reflector.
Access to the bulb is obtained by removing the
two screws which secure the plastic cover.
The correct bulb is Lucas No. 352, 6 volt, 3/18
watt for machines up to 250 c.c., or Lucas No.
384, 6 volt, 6/18 watt for larger capacity machines.
The 3 or 6 watt filament provides the normal tail
light, while the 18 watt filament is illuminated on
movement of the brake pedal.
Care must be taken that the leads to the stop
tail lamp are correctly connected, as the use of the
18 watt filament on the normal tail light will not
only discharge the battery but could cause trouble
Section G5d Page 2
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Section H5 Page 1
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compress these by hand. Heavier springs
having a rate of 130 lb. per inch are available
which may require the use of a spring
compressor, as shown in Fig. 2.
5. Removal of Swinging Arm Chain Stays
First remove one of the pivot pin nuts and
pull the pivot pin out from the other end. To
release the pivot bearing it is necessary to spread
the rear portion of the frame, using the frame
expander E.5431, which will spread the frame
sufficiently to enable the spigots on the thrust
washers to clear the recesses in the pivot lugs
forming part of the frame.
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4. Servicing Rear Suspension Units
The proprietary units fitted are sealed and
servicing of the internal mechanism can be
carried out only by the manufacturers.
The rubber bushes in the top and bottom
eyes can easily be renewed and the spring can
be removed by pushing down on the top spring
cover so as to release the split collar above it.
After removal of the split collar the top cover
and spring can be lifted off. When
reassembling, the spring should be greased to
prevent rust and squeaking if it should come
into contact with either of the covers.
The standard solo springs have a rate of
100 - 105 lb. per inch and it is not difficult to
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1. Description of Frame
The frame is built throughout of cold
drawn weldless steel tubing with brazed or
welded joints, liners being fitted where
necessary for extra strength. All the main
frame
members
are
made
of
chromemolybdenum alloy steel tubing which
retains its strength and resistance to fatigue
after brazing or welding.
The swinging arm unit which forms the
chain stays is fitted with large diameter
phosphor bronze bushes and pivots on a stout
steel tube which is secured to the main frame
by a long bolt passing through the pivot lugs.
Hardened steel thrust washers are provided to
deal with side thrust. The torsional rigidity of
the swinging arm unit helps to maintain the
rear wheel upright in the frame and thus
relieves the wheel spindle of bending stresses
to which it is subject with other types of rear
suspension.
2. Steering Head Races
The steering head races, 34085, are the
same at the top and bottom of the head lug and
are the same for all models. They are easily
removed by knocking them out with a hammer
and drift and new races can be fitted either
under a press or by means of a hammer and a
wooden drift.
3. Removal of Rear Suspension unit
On the "Constellation" and "Super Meteor"
from 1961 onwards, the valances on either side
of the frame must be removed to gain access to
the top pivot pin. See Section C, paragraph 8.)
The procedure for all models is then as
follows: Remove the top pivot pin nut, drive
out the pivot pin, then hinge the suspension
unit back on the lower pivot pin. After
removing the lower nut, the unit may be
pushed off the pivot pin welded to the fork
end.
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DUAL SEAT – MUDGUARD ASSEMBLY 1961 ONWARDS
Fig. 3
Section H5 Page 3
If it is necessary to remove the bronze bushes
these can be driven out by means of a hammer
and a suitable drift and new bushes can be fitted
under a press without difficulty. After fitting the
bushes they must be reamed to .844/.843 in.
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6. Centre Stand
To remove the centre stand unscrew the nut
from one end of the stand spindle, knock out the
latter and withdraw the stand complete with its
bearing sleeve after disconnecting one end of the
stand spring.
9. Dismantling the Rear Mudguard-dual Seat
Assembly, 1961 onwards
Having removed the assembly front the
frame as described in Section C, paragraph 8,
dismantling for repair or replacement is a simple
matter.
First remove the single, 3/16 in. bolt securing
the number plate, and disconnect the rear light
wire at the junctions. The lifting handles are next
pulled out, after undoing the two 5/16 in. nuts on
each handle. The grommets may be left in
position in the mudguard.
Take out the two 3/16 in. bolts in the nose of
the muduard. These screw into tapped holes in
the dual seat. When replacing, the shakeproof
washer must be next to the head of the bolt and
the large plain washer must be against the
underside of the mudguard.
Remove the single 3/16 in. nut and bolt attaching the rear of the mudguard to the carrier. Note
the large plain washer, this must be under the bolt
head, and bear against the top of the mudguard on
assembly. Also the shakeproof washer and metal
plate on the underside.
Lastly, the two 1/4 in. bolts attaching the
front of the carrier to the mudguard, and the two
5/16 in. bolts in the carrier bridge piece, can be
undone. They fit into tapped holes in the dual
seat
Note that shakeproof washers are fitted to all
bolts and studs. Plain washers must be placed as
described above and shown in Fig. 3.
On some early 1961 "Constellation" models,
this mudguard is made from glass-fibre and in
the event of damage small repair kits, consisting
of a quantity of resin, catalyst and glass fibre,
are available from our Service Department.
Instructions for carrying out minor repairs are
issued with this kit. All other models have the
mudguard of pressed steel.
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Section H5 Page 4
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8. Lubrication
The steering head races, swinging arm pivot
bearing and stand pivot bearing should be well
greased on assembly. The swinging arm pivot
and stand pivot are provided with grease nipples
but no nipples are provided for the steering head
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7. Wheel Alignment
Note that it is not possible to guarantee that
the wheels are correctly aligned when the same
notch position is used on both adjuster cams. It is
therefore not sufficient to count the notches and
use the same position on both sides of the
machine. The only way to guarantee that the
wheels are in line is to check the alignment from
front wheel to back using either a straight edge
or a piece of taut string. The alignment should be
checked on both sides of the machine and if the
front and rear tyres are of different section
allowance must be made for this.
It is usual to check the alignment of the
wheels at a point about six inches above the
ground but, if the alignment is checked also
towards the top of the wheels, it will be possible
to ascertain whether or not the frame is twisted
so as to cause one wheel to be leaning while the
other is vertical. To do this it is always necessary
to remove the mudguards and, unless a straight
edge cut away in its centre portion is available, it
will be necessary also to remove the cylinder,
toolboxes, battery, etc., in order to allow an
unbroken straight edge or a piece of taut string to
contact the front and rear tyres.
as experience has shown that the provision of
nipples at this point causes trouble through
chafing and cutting of control and lighting cables.
If the steering head bearings are well packed they
will last for several years or many thousands of
miles.
Recommended greases are Castrolease
(Heavy), Mobilgrease (No. 4), Esso Grease
Energrease C. I or Shell Retinax A.
SECTION J1
Front Fork
With Casquette and Aluminium Alloy Bottom Tubes
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2. Operation of the Fork
The fork provides a range of movement of 6
in. from the fully extended to the fully
compressed position. The movement is
controlled by the compression spring and by the
hydraulic damping system. The hydraulic
damping is light on the bump stroke and heavier
on the rebound stroke, thus damping out any
tendency to pitching or oscillation without
interfering unduly with the free movement of
the fork when the wheel encounters an obstacle.
The fork is filled with S.A.E. 20 to a point
above the lower end of the fork spring so that
the damper chamber "B" is always kept
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1. Description
The telescopic fork consists of two legs each
of which comprises a main tube of chrome
molybdenum alloy steel tubing which is
screwed into the Casquette fork head at the
upper end and securely clamped to the fork
crown. Fitted over the lower end of the main
tube is the bottom tube made of high strength
aluminium alloy with an integral lug which
carries the wheel spindle. Fitted on the lower
end of the main tube is a steel bush which is a
close fit in the bore of the bottom tube. The
upper end of the bottom tube carries a bronze
bush which is a close fit over the outside
diameter of the main tube. The bush is secured
to the bottom tube by means of a threaded
housing which contains an oil seal. A stud
known as the "spring stud" is fitted in the lower
end of the bottom tube and a valve port is
secured to the lower end of the main tube. As
the fork operates oil is forced between the
spring stud and the bore of the valve port
forming a hydraulic damping system. A
compression spring is fitted inside the main tube
between the upper end of the spring stud and the
upper end of the main tube. The lower end of
the main tube and upper end of the bottom tube
are protected by a cover secured to the fork
crown.
A special fork is available for sidecar
machines. This has bottom tubes with extended
wheel lugs giving less trail and is fitted with
stronger springs and a steering damper.
Section J1 Page 1
3. Dismantling the Fork to Replace Spring,
Oil Seal or Bearing Bushes
Place the machine on the centre stand,
disconnect the front brake control and remove the
front wheel and mudguard complete with stays.
Unscrew the bottom spring stud nut (38080)
which will allow oil to run out of the fork down
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full of oil. Upward movement of the wheel
spindle forces oil from the lower chamber "A"
through the annular space between the spring
stud (38067) and the bore of the main tube valve
port (38138) into the damper chamber "B."
During this stroke the pressure on the underside
of the valve plate (38073) causes this to lift so
that oil can also pass from "A" to "B" through
the eight holes in the valve body. Since,
however, the diameter of chamber "B" is less
than that of chamber "A" there is not room in
"B" to receive all the oil which must be displaced
from "A" as the fork operates. The surplus oil
passes through the cross hole in the spring stud
and up the centre hole in the stud, spilling out
through the nut (38076) which secures the upper
end of the spring stud to the bronze guide at the
lower end of the fork spring.
On the rebound stroke the oil in the damper
chamber "B" is forced through the annular space
between the spring stud and the bore of the main
tube valve port. During this stroke pressure in
chamber "B" closes the two disc valves at the
upper and lower ends of the chamber so that the
only path through which the oil can escape is the
annular space between the spring stud and the
port. Damping on the rebound stroke is therefore
heavier than on the bump stroke. At the extreme
end of either bump or rebound stroke a small
taper portion on the spring stud enters the bore
of the valve port, thus restricting the annular
space and increasing the amount of damping. At
the extreme end of the bump stroke the larger
diameter taper on the oil control collar (38075)
enters the main counterbore of the valve port
thus forming a hydraulic cushion to prevent
metal to metal contact.
Section J1 Page 2
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to the level of the cross-hole in the spring stud.
Now knock the spring stud upward into the fork
with a soft mallet, thus allowing the remainder
of the oil to escape. Pull the fork bottom tube
down as far as possible, thus exposing the oil
seal housing (38157). Unscrew this housing
either by means of a spanner on the flats with
which it is provided or by using the gland nut
handgrips (E.5417). The bottom tube can now
be withdrawn completely from the main tube,
leaving the bottom tube bush, oil seal housing
and oil seal in position on the main tube.
Now unscrew the main tube valve port using
"C" spanner (E5418). The spring stud and
spring can now be withdrawn from the lower
end of the main tube.
The steel main tube bush (38156) can now
be tapped off the lower end of the tube, if
necessary using the bottom tube bush for this
purpose. Before doing this, however, it is
advisable to mark the position of the bush with
a pencil line so as to ensure reassembling it in
the same position on the main tube. The reason
for this is that these steel bushes are finish
ground to size after fitting on to the tubes so as
to ensure concentricity to the main tube. After
removal of the main tube bush the bottom tube
bush, oil seal housing and oil seal can be
removed.In case of difficulty in removing the main
tube bush it is possible to withdraw the oil seal
housingafter loosening the crown clip bolt 39038,
removing the plug screw 38968 and unscrewing
the main tube from the fork-head by means of a
hexagon bar .500 in. across flats (Unbrako wrench
W. 11) or the special tool shown in Fig. 2.
up sharply against the spring until two or three
threads on the stud project beneath the end of
the bottom tube. Now fit the nut and washer and
pull the stud into position by tightening the nut.
If necessary fit the nut first without the washer
until sufficient thread is projecting to enable the
washer to be fitted.
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4. Spring
Solo and Sidecar springs are available. The free
length of each is 20.1/2 ins. The spring should be
replaced if it has closed by more than 1 inch.
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5. Reassembly of Parts
When refitting the oil seal, or fitting a new one,
great care must be exercised not to damage the
synthetic rubber lip which forms the actual seal. If
the seal has been removed from the upper end of
the main tube and is refitted from this end a
special nose piece (Fig. 3) must be fitted over the
end of the tube to prevent the thread from
damaging the oil seal.
The spring stud is a tight fit in the hole at the
lower end of the bottom tube. Once the stud has
been entered in the hole push the bottom tube
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6. Steering Head Races
The steering head bearing consists of two
deep groove thrust races each containing
nineteen 1/4 in. diameter balls. The bearing is
adjusted by tightening the steering stem locknut
after loosening the ball head clip screw and both
the fork crown clamp bolts. The head should be
adjusted so that, when the front wheel is lifted
clear of the ground, a light tap on the handlebars
will cause the steering to swing to full lock in
either direction, while at the same time there
should be only the slightest trace of play in the
bearings. When testing for freedom of
movement the steering damper, if fitted, should
be disconnected by unscrewing the anchor plate
pin. Do not forget to tighten the ball head clip
screw and fork crown clamp bolts. Before
tightening the latter make sure that the cover
tubes are located centrally round the main tubes
so that the bottom tube does not rub inside the
cover tube. A pair of split bushes (Fig. 5) is
useful to ensure centralisation of the cover tubes.
SHOWING THE POSITIONS OF THE CLAMP BOLTS
SECURING THE STEERING STEM AND FORK TUBES
Fig. 4
7. Removal of Complete Fork
The fork complete with front wheel and
mudguard can be removed from the machine if
necessary by adopting the following procedure.
Section J1 Page 3
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The leads to the lighting switch and ammeter
should be disconnected from the battery,
regulator, tail lamp, etc. at their lower ends or by
means of the plug and socket connectors when
these are provided. The switch and ammeter are
push fits into the rubber bushes (LU/365408) in
the fork head.
Disconnect the speedometer drive from the
speedometer head and unscrew the steering
damper knob and rod (if fitted) after removal of
the split pin through the lower end of the rod.
Undo the steering damper anchor plate pin so as
to disconnect the damper from the frame of the
machine.
Remove the two plug screws (38968) and
loosen the steering head clip bolt and the two
fork crown clamp bolts.
Now unscrew the fork main tubes from the
fork head and the steering stem locknut from the
top of the steering stem, turning each tube and the
nut a turn or two at a time. When the nut has been
removed from the steering stem and the main
tubes have been completely unscrewed from the
fork head the complete fork and wheel with
steering stem can be lifted out of the head lug of
the frame.
9. Air Vents
The earlier forks of this type were provided
with holes at the upper end of each main tube
communicating with small vent holes in the
Casquette head. Experience has shown that on
rough roads oil may escape through these air vents
which in consequence are now omitted. Escape of
oil from the earlier forks can be largely eliminated
by fitting specially long plug screws, which are
available. The Part Number is 40118. If these are
fitted and the final vent hole is stopped up with a
wooden plug leakage at this point is impossible.
Fitting the special plug screws alone is sufficient in
most instances.
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8. Lubrication
The lubrication of the fork bearings is effected
by the oil which forms the hydraulic damping
medium. All that is necessary is to keep sufficient
oil in the fork to ensure that the top end of the
bottom spring stud is never uncovered even in the
full rebound position. The level of oil in the fork
can be gauged by removing the top plug screw
and inserting a long rod about 3/8 in. diameter. If
slightly tilted this will ledge against the nut at the
upper end of the bottom spring stud and indicate
the level of oil above the stud. If the fork is empty
to start with the quantity required is
approximately 7.1/2 fluid ounces in each leg.
Recommended grades of oil are Castrolite,
Mobiloil Arctic, Essolube 20, B.P. Energol S.A.E.
20 and Shell X-100 20/20W.
Section J1 Page 4
SECTION K6
Front Wheel
With Dual 6in. Brake
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and unscrew the cover plate nuts 31347. The
right and left hand cover plate assemblies can
then be withdrawn from the respective brake
drums.
3. Removal of Brake Shoes and Springs
This is best done by unscrewing the pivot pin
locknuts, 28715, and the operating lever nuts,
10314, after which the assembly of brake shoes,
return springs, pivot pin and operating cam can
be removed from the cover plate by light blows
with a hammer and drift on the ends of the pivot
pin and the operating cam, see Fig. 2. The return
springs, 29236, can then be unhooked from the
spring posts in the brake shoes thus allowing the
whole assembly to fall apart.
4. Replacing Brake Linings
Brake linings are supplied either in pairs
ready drilled complete with rivets or ready
fitted to service replacement brake shoes.
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1. Removal from Fork
To remove the front wheel from the fork
place the machine on the centre stand and front
stand, if fitted, or alternatively with sufficient
packing (about 2 in.) beneath each side of the
stand to lift the wheel clear of the ground when
tilted back on to the rear wheel. Slacken brake
cable adjustments and disconnect cables from
handlebar lever and from operating cam levers
on hub. Unscrew the four nuts securing the fork
bottom tube lug caps (Part No. 38593) and allow
the wheel to drop forwards out of the front fork.
Make sure that the machine stands securely on
the rear wheel and centre stand-if necessary
place a weight on the saddle or a strut beneath
the fork to ensure this.
2. Removal of Brake Cover Plate Assemblies
Lock the brake "on" by pressure on the
operating lever, 38905 (R.H.) or 38906 (L.H.),
Section K6 Page 1
When riveting linings to shoes secure the two
centre rivets first so as to ensure that the lining
lies flat against the shoe. Standard linings are
Ferodo MR41, which are drilled to receive
cheese headed rivets.
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the inner edge of the outer race of the bearing
and the back of the recess in either end of the
hub barrel. To prevent any possibility of
sideways movement of the hub barrel on the
bearings it is, therefore, necessary for the
bearings to be a tight fit in the barrel but this fit
must not be so tight as to close down the outer
race of the bearing and thus overload the balls.
The following are the manufacturing tolerances
which control the fit of the bearings. The figures
for the bearings themselves are for SKF bearings
but other manufacturers' tolerances are similar.
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Bearing o/d
Housing bore
Bearing bore
Shaft diameter
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REMOVAL OF BRAKE SHOE ASSEMBLY
Fig. 2
8. Refitting Ball Bearings
To refit the bearings in the hub two hollow
drifts are required, as shown in Fig. 3. One
bearing is first fitted to one end of the spindle by
means of the hollow drift; the spindle and
bearing are then entered into one end of the hub
barrel which is then supported on one of the
hollow drifts. The other bearing is then threaded
over the upper end of the spindle and driven
home by means of the second hollow drift either
under a press or by means of a hammer which
will thus drive both bearings into position
simultaneously. In order to make quite sure that
there is clearance between the inner faces of the
outer bearing races and the bottom of the
recesses, fit the distance washer 30538, and the
cover plate nuts, 31347, with either the cover
plates themselves or additional packing washers
behind the nuts. Tightening the nut should not
have any effect on the ease with which the
spindle can be turned. If tightening the nuts
makes the spindle hard to turn this may be taken
as proof that the bearings are bottoming in the
recesses in the hub barrel before they are solid
against the shoulders on the spindle. In this cage
the bearing should be removed and a thin
packing shim fitted between the inner race and
the shoulder on the spindle.
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Section K6 Page 2
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5. Removal of Hub Spindle and Bearings
To remove the hub spindle and bearings
having already removed the brake cover plate
assemblies, lift out the felt washers, Part No.
21466, and distance washers, Part No. 30538.
Now hit one end of the wheel spindle with a
copper hammer or mallet, thus driving it out of
the hub bringing one bearing with it and leaving
the other in position in the hub. Drive the
bearing off the spindle and insert the latter once
more in the hub at the end from which it was
removed. Now drive the spindle through the hub
the other way, when it will bring out the
remaining bearing.
6. Hub Bearings
These are deep groove single row journal ball
bearings 5/8in. i/d by 1.9/16in. o/d by 7/16in.
wide. The Skefko Part No. is RLS5. Equivalent
bearings of other makes are Hoffmann LS7,
Ransome and Marles LJ5/8in., Fischer LS7.
7. Fitting Limits for Bearings
The fit of the bearings in the hub barrel is
important. The bearings are locked on the
spindle between shoulders and the distance
pieces, 30538, which in turn are held up by the
cover plate nuts 31347. In order to prevent
endways pre-loading of the bearings it is
essential that there is a small clearance between
1.5622/1.5617 in.
1.5620/1.5616 in.
0.6252/0.6247 in.
0.6252/0.6248 in.
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9. Reassembly of Brake Shoes to Cover Plates
Assemble each pair of shoes with their return
springs on to the pivot pin and operating cam,
putting a smear of grease in the grooves of the
pivot pin and on the operating faces of the cam.
Now fit the assembly into the cover plate,
putting a smear of grease on to the cylindrical
bearing surface of the operating cam and secure
with the pivot pin locknut, 28715, and washer,
17551. Fit the operating lever, 38905 or 38906,
on its splines in a position to suit the extent of
wear on the linings and secure with the nut,
10314, and washer, 14613. Note that the
position of the operating levers may have to be
corrected when adjusting the brake after refitting
the wheel. The range of adjustment can be
extended by moving these levers on to different
splines. Limit of wear is reached when the cam
is turned through nearly 90° with the brake hard
on so that there is a danger that the operating
springs cannot return the brake to the off
position.
brakes are
to take any
two linings
brake shoe
11. Refitting Brake Cover Plates
After assembling the brake shoe pivot pins
and operating cams into the cover plates repack
the hub bearings with grease. The recommended
greases are Castrolease (Heavy), Mobilgrease
(No. 4), Esso Grease, Energrease C3 or Shell
Retinax A. These are all medium heavy lime
soap or aluminium soap greases. The use of
H.M.P. greases which have a soda soap base is
not recommended as these tend to be slightly
corrosive if any damp finds its way into the
hubs.
Before fitting the distance washers and felt
washers make sure that the inside of the brake
drums are quite clean and free from oil or
grease, damp, etc., and replace the brake cover
plate assemblies. Securely tighten the cover
plate nuts, 31347.
12. Wheel Rim
The rim is Type WM2-19 in. plunged and
pierced with forty holes for spoke nipples. The
spoke holes are symmetrical, i.e., the rim can be
assembled to the hub either way round. Rim
diameter after building is 19.062 in., tolerances
on the circumference of the rim shoulders where
the tyre fits being 59.930/59.870 in. The
standard steel measuring tape for checking rims
is 5/16in. wide, .011 in. thick and its length is
59.964/ 59.904 in.
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10. Floating Cam Housings
Note that the cam housings, Part No. 26836,
are intended to be left free to float. The bolt
holes in the cam housings are slotted and the
securing pins, Part No. 252, are provided with
double coil spring washers beneath their heads
to enable them to be tightened sufficiently to
prevent the cam housings moving under the
influence of road shocks, while at the same time
they can be, and should be, left free enough to
be capable of being moved by hand in the
direction of the slots. The pins, 252, are secured
by locknuts, 7916, which are centre punched as
an additional precaution.
The leading shoes (i.e., those towards the rear
of the machine) have a servo action which
renders them more effective than the trailing
shoes. This servo action causes the linings on the
leading shoes to wear more quickly than those on
the trailing shoes and at the same time tends to
lift the leading shoes off the cams and press the
trailing shoes harder on to the cams. With a fixed
cam housing the result is that the majority of the
cam pressure is applied to the less efficient
trailing shoe. By leaving the housing free to float
the cam can follow up the leading shoe thus
maintaining equal pressure between the cam and
the two shoes and so making full use of the more
efficient leading shoe. Owing to the servo action
the wear on the leading shoe with a floating cam
housing is greater than that of the trailing shoe
and in time the limit of float of the cam housing
will be reached, after which the brake will
continue to function as a fixed cam brake with
some loss of efficiency. This can be restored by
removing the shoes and fitting them in the
opposite positions. Floating cam
self-centering and there is no need
special precautions to see that the
are of equal thickness or that the
assembly is centred in the drum.
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13. Spokes
The spokes are of the single butted type 8-10
gauge with 90° countersunk heads, angle of
bend 95°-100°, length 65/8 in., thread diameter
.144 in., 40 threads per inch, thread form British
Standard Cycle.
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14. Wheel Building and Truing
The spokes are laced one over two and the
wheel rim must be built central in relation to the
nuts which secure the brake cover plates. The
rim should be trued as accurately as possible, the
maximum permissible run-out both sideways
and radially being plus or minus 1/32in.
15. Tyre
The standard tyre is Dunlop 3.25-19in.
Ribbed tread.
When removing the tyre always start close to
the valve and see that the edge of the cover at
the other side of the wheel is pushed down into
the well in the rim.
Section K6 Page 3
17. Lubrication
No grease nipple is provided on later hubs.
due to the tendency to over-grease, resulting in
grease finding its way past the felt seal; on to the
brake linings.
The correct method of lubrication is to pack
the bearings with grease after dismantling the
hub, as described above.
Note that the brake cams are drilled for
grease passages but the ends of these are
stopped up with countersunk screws instead of
being fitted with grease nipples. This is done to
prevent excessive greasing by over-enthusiastic
owners. If the cams are smeared with grease on
assembly they should require no further
attention but in case of necessity it is possible to
remove the screws, fit grease nipples in their
place and grease the cams by this means.
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When replacing the tyre fit the part by the
valve last, also with the edge of the cover at the
other side of the wheel pushed down into the
well.
If the correct method of fitting and removal of
the tyre is adopted it will be found that the
covers can be manipulated quite easily with the
small levers supplied in the toolkit. The use of
long levers and/or excessive force is liable to
damage the walls of the tyre. After inflation
make sure that the tyre is fitting evenly all the
way round the rim. A line moulded on the wall
of the tyre indicates whether or not the tyre is
correctly fitted. If the tyre has a white mark,
indicating a balance point, this should be fitted
near the valve.
16. Tyre Pressure
The recommended pressure for the front tyre
is 18lb. per square inch for wheel loads up to
240lb.
Section K6 Page 4
SECTION L9
Rear Wheel
EXPLODED VIEW OF QUICKLY DETACHABLE REAR HUB
Fig. 1
1. Description
This wheel is of the "detachable" type, which
enables the main portion of the wheel to be
removed from the machine without disturbing
the chain or brake. The wheel incorporates the
well-known Enfield cush drive and also a 7in.
internal expanding brake.
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(Quickly Detachable Type with 7 in. diameter
Brake and Full-Width Hub)
2. Removal and Replacement of Main
Portion of Wheel for Tyre Repairs, etc.
Place the machine on the centre stand, if
necessary putting packing pieces beneath the
legs of the stand to lift the wheel clear of the
ground. Unscrew the loose section of the spindle
and withdraw this, together with the chain
Section L9 Page 1
Make sure also that the speedometer drive
gearbox is correctly positioned so that there is
no sudden bend in the driving cable. When
replacing the connecting link in the driving
chain, make sure that the closed end of the
spring link points in the direction of travel of the
chain. Replace the chain adjuster cams in their
original positions or, if necessary, turn each of
them the same number of notches to tension the
chain and maintain correct wheel alignment. If
the chain is adjusted, it will be necessary to
reposition the front part of the chaincase. This is
easily done by slackening the two screws
fastening it to the swinging arm chainstay before
re-assembling the chaincase to the brake cover
plate, then re-tightening the screws. Do not
forget to refit the brake rod and adjust the brake
so that the wheel turns freely when the brake is
off, while at the same time only a small travel of
the brake pedal is necessary to put the brake on.
4. Removal of Brake Shoes for Replacement.
Remove the complete wheel as described
above, then remove the spindle nut, chain
adjuster and the distance collar, thus permitting
the complete brake cover plate assembly, with
operating cam, pivot pin, shoes and return
springs, to be lifted off the hub spindle. The
brake shoes can then be removed after detaching
the return springs. Brake linings for alloy shoes,
are supplied either in pairs ready drilled
complete with rivets (Part No. 4246913X) or
ready fitted to service replacement brake shoes
(Part No. 41342SR). When riveting linings to
shoes, secure the two centre rivets first so as to
ensure that the lining lies flat against the shoe.
Standard linings are Ferodo MS3, which are
drilled to receive cheese headed rivets.
5. Removal of Brake Operating Cam
To remove the operating cam unscrew the nut
which secures the operating lever to the splines
on the cam. A sharp tap on the end of the cam
spindle will now free the lever, after which the
cam can be withdrawn from its housing.
Do not try to remove the brake shoe pivot pin
and nut, as these are brazed to the cover plate.
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Section L9 Page 2
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* Note that the wheel is not necessarily correctly lined
up when the same notch position is used on both adjuster
cams. Once the position of the cams which gives correct
alignment has been found this alignment will, however, be
maintained if both cams are moved the same number of
notches.
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3. Removal and Replacement of Complete
Wheel for Access to Brake
Place the machine on the centre stand and
remove the rear mudguard unit. Disconnect the
rear driving chain at the spring link and loop the
top end of the chain over the tag provided at the
top of the fixed portion of the chaincase. Pull on
the other end of the chain and allow it to hang.
Unscrew the rear brake rod adjusting nut
completely and depress the brake pedal so as to
disengage the rod from the trunnion in the brake
operating lever. Unscrew the brake cover plate
anchor nut and remove this together with the
washer behind it. Unscrew the loose section of
the spindle two or three turns and the spindle nut
by a similar amount. Mark the chain adjuster
cams to ensure replacing in the same position.*
Disconnect the speedometer driving cable and
slide the wheel out of the fork ends, tilting it so
as to disengage the end of the brake shoe pivot
pin from the slot in the fork end.
When replacing the wheel make sure that the
dogs on the gear in the speedometer drive
gearbox are engaged with the slots in the end of
the hub barrel.
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adjuster cam, preferably marking it to ensure
that it is replaced in the same position. Now
slide the distance collar out of the fork end and
lift away the speedometer drive gearbox, which
can be left attached to the driving cable. The
spacing collar and the felt washer behind it may
now be removed to prevent risk of them falling
out when manipulating the tyre. If, however,
these are too tight a fit in the hub to come out
easily they may be left in place. The main body
of the wheel can now be pulled across to the
right-hand side of the machine, thus disengaging
the six driving pins from the cush drive shell and
enabling the wheel to be removed from the
machine.
When replacing the main portion of the
wheel, reverse the foregoing procedure. The
cush drive shell can be prevented from rotating
when turning the wheel to engage the six driving
pins, if the machine is placed in gear or the rear
brake is operated, taking care, when replacing
the speedometer drive gearbox, that the driving
dogs inside the gearbox engage with the slots in
the end of the hub barrel. Before tightening the
centre spindle make sure that the speedometer
drive gearbox is correctly positioned so that
there is no sharp bend in the driving cable.
6. Cush Drive
The sprocket brake drum is free to rotate on
the hub barrel. Three radial vanes are formed on
the back of the brake drum and three similar
vanes are formed on the cush drive shell. Six
rubber blocks are fitted between the vanes on the
brake drum and those on the cush drive shell,
thus permitting only a small amount of angular
movement of the sprocket/brake drum relative
liberally with grease where it fits over the hub
barrel.
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RE-ASSEMBLY OF CUSH DRIVE
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to the hub barrel and transmitting both driving
and braking torques and smoothing out
harshness and irregularity in the former.
If the cush drive rubbers become worn so that
the amount of free movement measured at the
tyre exceeds ½ in. to 1 in., the rubbers should be
replaced. To obtain access to them remove the
complete wheel as described above; then unscrew
the loose section of the spindle completely. The
main portion of the wheel can then be lifted away
from the assembly consisting of the fixed portion
of the spindle, sprocket/brake drum complete
with brake and the cush drive shell. Now remove
the brake cover plate complete with brake shoes
as described above, and unscrew the three nuts at
the back of the cush drive shell after bending
back the locking washers. The three studs are
brazed to the lockring and should be driven out
of the cush drive shell, each a little at a time to
avoid distorting the lockring or bending the studs.
The sprocket/brake drum can now be separated
from the cush drive shell, and the six cush drive
rubbers lifted out.
When reassembling the cush drive the entry
of the vanes between the rubbers will be
facilitated if the latter are fitted into the driving
shell first and then tilted. The rubbers should be
liberally smeared with soapsuds to facilitate
entry of the vanes. Grease the inner face of the
lockring before assembling and tighten the three
nuts down solid as there is a shoulder on the stud
which prevents tightening of the nuts from
locking the operation of the cush drive. Do not
forget to bend up the tabs of the three locking
washers.
When reassembling the cush drive, coat the
inside of the bore of the sprocket/brake drum
7. Removal of Ball Bearings
To remove the ball bearings take the
complete wheel out of the machine and separate
the main portion of the wheel from the
sprocket/brake drum, cush drive shell assembly,
as described above. To remove the bearing from
the sprocket/brake drum, first remove the brake
cover plate complete with brake shoe assembly;
then remove the distance collar and unscrew the
bearing retaining ring with peg spanner. Now
screw the loose section of the spindle into the
fixed section and drive out the bearing by hitting
the hexagon headed end of the loose section of
the spindle.
To remove the bearings from the loose half of
the hub barrel, first lift away the distance collar,
speedometer drive gearbox, the spacing collar
and the felt washer. Remove the bearing
retaining circlip from the driving sprocket end of
the barrel. Between the two bearings is a spacer,
slotted at one end to enable a drift to be used on
the bearing at that end. Remove this bearing
first, then enter the loose section of the spindle
into the spacer and drive out the remaining
bearing by means of a hammer and drift applied
to the hexagon headed end of the spindle.
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8. Hub Bearings
These are deep-groove Single-row journal
ball bearings. The sprocket/brake drum bearing
is a Skefko RLS7, 7/8 in. i/d, by 2 in. o/d, by
9/16 in. wide. Equivalent bearings of other
makes are Hoffmann LS9, Ransome & Marles
LJ 7/8 in., and Fischer LS9. The two bearings in
the hub barrel are Skefko RLS5, 5/8 in. i/d, by
1.9/16 in. o/d, by 7/16 in. wide. Equivalent
bearings of other makes are Hoffmann LS7,
Ransome & Marles LJ 5/8 in., and Fischer LS7.
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9. Removal of Hub Driving Pins
To remove the six driving pins from the
aluminium full width hub, first remove the hub
cap after unscrewing the three screws attaching it
to the hub. Unscrew the six Simmonds nuts and
drive out the pins.
10. Refitting Ball Bearings
To refit the sprocket/brake drum bearing, use
a hollow drift as shown in Fig. 3. The bearing is
first fitted to the fixed section of the spindle; the
spindle and bearing are then entered into the
sprocket/brake drum and driven home,
preferably under a press or using light hammer
blows.
The two bearings in the hub barrel are
pressed in, using the drift part of E.4823. First
Section L9 Page 3
assemble the bearing into the circlip grooved end
of the barrel and fit the circlip. Replace the
bearing spacer, the slot in the spacer can be at
either end of the hubs, and assemble the second
bearing, supporting the hub on the inner race of
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DRIFT FOR RE-FITTING BEARING
Fig. 3
13. Final Reassembly of Hub Before
Replacing Wheel
Before replacing the felt washers which form
the grease seals, pack all bearings with grease.
Recommended greases are Castrolease (Heavy).
Mobilgrease (No. 4), Esso Grease, Energrease
C3 or Shell Retinax A. These are all medium
heavy lime soap or aluminium soap greases. The
use of H.M.P. greases which have a soda soap
base is not recommended as these tend to be
slightly corrosive if any damp finds its way into
the hubs.
Make sure that the inside of the brake drum is
quite free from oil or grease, damp, etc. Replace
the felt washers, distance collars, the brake cover
plate assembly, speedometer drive gearbox,
distance collars, chain adjuster cams, the loose
section of the spindle and the spindle nut. The
wheel is then ready for reassembly into the
machine.
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the other bearing. If the drift part of E.4823 is
not available it is essential that the last bearing is
assembled by applying pressure to both inner
and outer races simultaneously to avoid
pre-loading the two hub barrel bearings.
the trailing or leading shoe first makes contact
with the drum. With the brake assembly
correctly centred and the screws securing the
cam housing correctly tightened wear on both
linings should be approximately equal.
14. Wheel Rim
The wheel rim is type WM2-19 in. plunged
and pierced with forty holes for spoke nipples.
The spoke holes are symmetrical, i.e., the rim
can be assembled to the hub either way round.
The rim diameter after building is 19.062 in.,
the tolerances on the circumference of the rim
shoulders where the tyre fits being
59.930/59.870 in. The standard steel measuring
tape for checking rims is 5/16 in. wide, .011 in.
thick, and its length is 59.964 59.904 in.
15. Spoke
The spokes are of the single butted type, 810 gauge, with 90o countersunk heads, thread
diameter .144 in., 40 threads per inch, thread
form British Standard Cycle. The inner spokes
are 6.5/8 in. long with an angle of bend 100o,
and the outer spokes 6.3/4 in. long with an angle
of bend 80o. One security bolt is fitted. There is
also a balance weight clipped to a spoke by
means of a small screw.
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Section L9 Page 4
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12. Centering Cam Housing
Note that the bolt holes in the cam housing
are slotted, thus enabling the brake shoe
assembly to be centred in the drum. It is not
intended that on rear brakes the cam housing
should be left free to float but the shoes should
be centred by leaving the screws just short of
dead tight. The brake cover plate assembly with
the shoes should then be fitted over the spindle
into the brake drum and the brake applied as
hard as possible by means of the operating lever.
This will centre the shoes in the drum. The
screws should then be tightened dead tight and
secured with the locknuts. If the shoes are not
correctly centred the brake will be either
ineffective or too fierce, depending on whether
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11. Reassembly of Brake Shoes and
Operating Cam into Cover Plate
No difficulty should be experienced in
carrying out these operations. Put a smear of
grease in the grooves of the pivot pin and on the
operating face of the cam; also on to the
cylindrical bearing surface of the operating cam
if this has been removed. Fit the operating lever
and trunnion on its splines in a position to suit
the extent of wear on the linings and secure with
the nut. The range of adjustment can be extended
by moving the lever on to a different spline.
16. Wheel Building and Truing
The spokes are laced one over two and the
wheel rim must be built central in relation to the
outer faces of the distance collars. The rim
should be trued as accurately as possible, the
maximum permissible run-out both sideways and
radially being plus or minus 1/32 in.
indicating a balance point, this should be fitted
near the valve.
18. Tyre Pressures
The recommended pressures for the rear tyre
are 20 lb. per sq. in. for a solo rider and 32 lb.
per sq. in when a pillion passenger is carried.
19. Lubrication
Grease the bearings by packing them with
grease after dismantling the hub as described
above.
Note that the brake cam is drilled for a grease
passage but the end of this is stopped up with a
countersunk screw instead of being fitted with a
grease nipple. This is done to prevent excessive
greasing by over-enthusiastic owners. If the cam
is smeared with grease on assembly it should
require no further attention but in case of
necessity it is possible to remove the screw, fit a
grease nipple in its place and grease the cam by
this means.
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17. Tyre
The standard tyre is Dunlop 3.50-19 in.
studded tread.
When removing the tyre always start close to
the valve and see that the edge of the cover at
the other side of the wheel is pushed down into
the well in the rim.
When replacing the tyre fit the part by the
valve last, also with the edge of the cover at the
other side of the wheel pushed down into the
well.
If the correct method of fitting and removal
of the tyre is adopted it will be found that the
covers can be manipulated quite easily with the
small levers supplied in the tool-kit. The use of
long levers and/or excessive force is liable to
damage the walls of the tyre. After inflation
make sure that the tyre is fitting evenly all the
way round the rim. A line moulded on the wall
of the tyre indicates whether or not the tyre is
correctly fitted. If the tyre has a white mark
Section L9 Page 5
SECTION M6
Special Tools
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Section M6 Page 1
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Section M6 Page 2
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Section M6 Page 3
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Section M6 Page 4
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Section M6 Page 5
SECTION Pl
"Airflow" Fairing
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1. Description of the Fairing
The "Airflow" fairing and front mudguard
are fibre glass units and therefore very light,
rigid and tough. The fairing, with the
windscreen, provides full weather protection. It
has two cubby holes and incorporates the
headlamp, speedometer, ammeter and lighting
switch.
On the rare occasions that it may be
necessary to remove the mudguard and fairing
from the machine, it will be found to present no
difficulty if the following sequence is adopted:
5. Removal of the Front Wheel and Fork Legs
To remove the front wheel from the fork,
place the machine on the centre stand with
sufficient packing (about 2 in.) beneath each side
of the stand to lift the wheel clear off the ground
when tilted back on to the rear wheel. Slacken
the brake cable adjustment and disconnect the
cable from the handlebar lever and from the
operating cam lever on the hub. Unscrew the
four nuts securing the fork leg caps and allow the
wheel to drop forward out of the front fork.
Make sure that the machine stands securely on
the rear wheel and centre stand-if necessary
place a weight on the saddle or a strut beneath
the fork to ensure this.
Unscrew the plug screws in the fork head,
when the sliding fork legs, complete with springs
and spring distance tubes, can be withdrawn
from the lower ends of the main tubes.
6. Removal of the Front Mudguard
From the top of the fairing the two clamp
bolts holding the mudguard to the fork crown
can be reached. Unscrew the nuts and push out
the bolts.
On early models it is necessary to remove the
centre pin securing the guard to the bottom of
the steering stem. The mudguard may now be
withdrawn.
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4. Removal of the Headlamp Switch,
Speedometer and Ammeter
Undo the switch knob screw and remove the
knob. Unscrew the switch plate nut and remove
the switch plate. The switch body may now be
pulled out from beneath the fairing. Do not lose
the plain washer situated beneath the switch
knob.
Disconnect the speedometer drive, and, after
removing two nuts, the spring washers and the
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3. Removal of the Headlamp
Take out the small screw from the underside
of the headlamp rim. Raise the rim to clear its
spigot plate from the slot in the lamp body shell
and remove. Next take off the rubber ring from
the light unit. By slackening the three light unit
adjuster screws and rotating the light unit in an
anti-clockwise direction, the unit may then be
withdrawn sufficiently to disconnect the four
leads.
Should it be necessary to remove the lamp
body shell this may be done by unscrewing the
four screws spaced round its flange. This also
releases the rubber washer. Care should be taken
not to lose the four screw locking plates inside
the fairing.
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2. Removal of the windscreen
Remove the two screws which attach the
number plate to the fairing. Removal of the
number plate will expose a screw in the centre
of the fairing which may now be taken out,
together with the screws at each corner of the
screen. The screen and metal back plate may
now be lifted clear, taking care not to lose the
five female screws with their plain steel and
rubber washers.
bridge piece from the bottom of the speedometer,
it may be removed.
To remove the ammeter it is only necessary to
take off the rubber band from the body of the
ammeter, after disconnecting the leads, and press
down the small metal tabs which will be found
turned outwards. The ammeter will then pull out
from the top of the fairing.
7. Removal of the Fairing
First take off the exhaust pipe. This is held to
one of the front engine bearer bolts and to the
pillion footrest stud at the rear.
Slacken the hose clips and remove the
attachment caps from the ends of the attachment
stud to which the lower part of the fairing is
anchored.
Unscrew the nuts and push out the stud which
secures the upper part of the fairing to the tube
extending forward from the steering head.
If required the two bottom attachment studs
may be removed.
Section P1 Page 1
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Section P1 Page 2
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Section P1 Page 3
8. Repairs
In the event of damage to the fairing, small
repair kits consisting of a quantity of resin,
catalyst and glass fibre are available from our
Service Department. Instructions for carrying
out minor repairs are issued with this kit.
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9. Reassembly of the
Fairing
If these have been removed replace the two
bottom fairing attachment studs, also fit the
rubber sleeve to the down tube. Next raise the
fairing over the fork cover tubes, locating the
bottom attachment plates on each leg shield
over the attachment studs.
Incline the fairing outwards and thread the
light and switch leads through the strut tube
aperture, and the speedometer cable through the
smaller hole below it. The fairing can then be
pushed towards the forks until the strut tube,
complete with buffer assembly, has entered the
aperture and is positioned between the strut tube
attachment plates. Fit the stud through the buffer
assembly and attachment plates and secure
washers and nuts to either end.
Complete the fairing assembly to the
machine by fixing the attachment cap over the
attachment stud rubber. Compress these parts
together and secure with the attachment clip.
The exhaust system may now be fitted.
lamp wire, through the hole in the lamp body
shell. Fit the body shell rubber washer between
the fairing and the lamp body shell rim, and line
up the holes in the shell rim, the washer and the
fairing aperture rim. Secure with the four screws
and locking plates, keeping the threaded plate at
the bottom.
Connect the blue and red and the blue and
white wires to the main bulb wires in the back of
the light unit. Push the green and brown lead
into the pilot lamp socket and the single red
earth wire from the main harness into the socket
on the main bulb fitting.
The light unit may now be pushed over the
three adjusters, after first slackening them. Turn
the light unit in a clockwise direction to secure.
Afterwards tighten all the adjusters as far as
possible.
Place the rubber ring over the light unit, with
the face marked "BACK" facing the light unit
rim. Locate the spigot plate, situated on the top
underside of the rim, with the slot in the lamp
body shell. Press the rim downwards and screw
in the pin at the bottom of the rim.
Finally, adjust the aim of the light beam by
turning the adjuster screws in a clockwise
direction from the rear as neccessary. Do not
turn them further than required, not more than
two screws will need adjusting.
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Section P1 Page 4
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11. Reassembly of Headlamp
Thread the red earth wire, the blue and red,
and the blue and white main bulb wires from the
dipper switch, and one green and brown pilot
12. Reassemble of Ammeter, Headlamp
Switch and Speedometer
Insert the ammeter into the off-side hole in
the fairing, turn up under the fairing the small
tabs on the ammeter, and fit the rubber ring,
pushing it up as far as possible. Connect up the
two wires with the tab washer type connections
to the ammeter terminals.
Push the switch up from the underside of the
fairing, place in position the switch plate and
secure with the nut. Finally, put on the small
washer and the switch knob, and secure with the
screw.
Push the speedometer into the fairing from
above, and secure the bracket with the nuts and
washers from below. Fit the speedometer drive
and lamp.
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10. Reassembly of Mudguard, Fork Legs
and Wheel
Fit the two sealing washers to the fork cover
tubes, not forgetting the small sealing washer for
the fork crown extension tube on Early Models.
Raise the mudguard, and thread the cover tubes
(and the fork crown extension when fitted)
through their respective holes. Line up the
mudguard bracket holes with the fork crown clip
bolt holes and fit the bolts, washers and nuts
finger tight. (On Early Models fit the fork crown
extension stud and washer.)
Slide the fork legs up into the fork head.
Centralise the fork leg top with the cover tube,
and push up to the full extent. Fit and tighten the
plug screws in the fork head.
The fork crown clip bolts may now be
tightened.
Replace the wheel and connect up the brake
cable at both ends. Do not forget to readjust
the brake.
13. Reassembly of Windscreen
Put the female screws, with their plain steel
and rubber washers, into the back plate and
windscreen, and line up with the holes in the
fairing. Be sure to use the shortest male screw
for the centre countersunk hole, and the two
longest for attaching the number plate.
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SPARES for ROYAL ENFIELD & AMAL
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HITCHCOCK’S MOTORCYCLES
ROSEMARY COURT
OLDWICH LANE WEST
CHADWICK END
SOLIHULL
B93 0EY
ENGLAND
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TELEPHONE: 01564 783 192
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FAX: 01564 783 313
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E-MAIL: [email protected]
WEB: hitchcocksmotorcycles.com
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