Betamotor | EVO 4t | 2007 Evo (4 stroke) engine

2007 Evo (4 stroke) engine
WORKSHOP MANUAL
WORKSHOP MANUAL
INDEX
INTRODUCTION ...................................................................................................... 1
CHAPTER 1
LUBRICATION CIRCUIT
1 LUBRICATION CIRCUIT ..........................................................................
1.1 ENGINE OIL ......................................................................................................
1.2 CHECKING THE ENGINE OIL LEVEL ...............................
1.3 CHANGING THE ENGINE OIL ..................................................
6
6
7
7
CHAPTER 2
ENGINE REMOVAL AND REFITTING
2 ENGINE REMOVAL AND REFITTING ................................. 10
2.1 ENGINE REMOVAL ............................................................................... 10
2.2 REFITTING THE ENGINE .............................................................. 17
CHAPTER 3
DISMANTLING
3 DISMANTLING ................................................................................................. 18
3.1 DRAINING THE OIL ............................................................................ 18
3.2 IGNITION ........................................................................................................... 19
3.3 CYLINDER HEAD .................................................................................... 19
3.4 CYLINDER ....................................................................................................... 22
3.5 FLYWHEEL ....................................................................................................... 22
3.6 OIL PUMP (LEFT-HAND CRANKCASE) ................... 23
3.7 CLUTCH .............................................................................................................. 24
3.8 PRIMARY TRANSMISSION ....................................................... 26
3.9 KICKSTART ...................................................................................................... 27
3.10 SHIFTING MECHANISM ........................................................... 27
3.11 OIL PUMP (RIGHT-HAND CRANKCASE) .......... 28
3.12 TIMING SPROCKET ........................................................................ 29
3.13 SPLITTING THE CRANKCASE ............................................ 29
3.14 GEARBOX AND SHIFTING MECHANISM .......... 30
3.15 CRANKSHAFT ......................................................................................... 31
CHAPTER 4
ASSEMBLY
4.1 RIGHT-HAND CRANKCASE .....................................................
4.2 LEFT-HAND CRANKCASE ...........................................................
4.3 CLUTCH CASING ....................................................................................
4.4 GEARBOX AND SHIFTING MECHANISM ..............
4.4.1 Mainshaft ............................................................................................
4.4.2 Layshaft .................................................................................................
32
34
35
37
37
38
4.5 CRANK ASSEMBLY .............................................................................. 40
4.6 CLOSING THE CRANKCASE ..................................................... 41
4.7 SHIFTING MECHANISM ............................................................... 42
4.8 TIMING SPROCKET ............................................................................ 44
4.9 OIL PUMPS ................................................................................................... 45
4.10 KICKSTART .................................................................................................. 48
4.10.1 Preassembly of kickstart shaft .......................... 48
4.10.2 Assembling the kickstart ........................................... 49
4.11 PRIMARY TRANSMISSION GEAR ................................ 49
4.12 CLUTCH .......................................................................................................... 50
4.13 FLYWHEEL ................................................................................................... 53
4.14 PISTON AND CYLINDER .......................................................... 54
4.14.1 Measurements and checks ................................... 54
4.14.1.1 Cylinder ........................................................................................ 54
4.14.1.2 Piston .............................................................................................. 54
4.14.2 Fitting .................................................................................................... 56
4.14.2.1 Studs ................................................................................................ 56
4.14.2.2 Piston .............................................................................................. 56
4.14.2.3 Cylinder ......................................................................................... 57
4.15 CYLINDER HEAD COVER ........................................................ 58
4.16 CYLINDER HEAD ............................................................................... 59
4.16.1 Checks ................................................................................................. 59
4.16.2 Fitting ..................................................................................................... 61
4.17 VALVEGEAR ................................................................................................ 62
4.17.1 Pre-assembly of camshaft ....................................... 62
4.17.2 Fitting the valvegear ........................................................ 63
4.18 CLUTCH CASING ................................................................................ 66
4.19 IGNITION ...................................................................................................... 68
4.20 FINAL DETAILS ...................................................................................... 69
III
betamotor.com
INTRODUCTION
FOREWORD
This publication is addressed to the user of the motorcycle and to technical assistance staff.
It has been written with the objective of making known, and comprehensible, the operations involved in the inspection, maintenance and repair of the motorcycle it deals with.
N.B. Read this manual carefully and from start to finish before carrying out any work on the
engine. A good knowledge of all the components that make up the engine, and of all the procedures to be followed during the various inspection and maintenance jobs, will help to prolong
the life of the engine.
The manual has been made as comprehensive as possible through the addition of diagrammatic illustrations that help clarify the subject at hand.
Note for information
Betamotor S.p.A. is committed to a policy of continuous improvement of its products.
For this reason it is possible that you will encounter slight differences between what is
stated in this manual and the vehicle on which you are about to carry out repair and/or
maintenance. Betamotor models are exported to numerous countries, where different
rules apply with respect to highway law and homologation procedures. Trusting that you
will understand, Betamotor S.p.A. therefore believes that it must reserve the right to
make alterations to its products and technical documentation at any time and without
prior notice.
We respect and defend the environment.
Everything we do has repercussions for the the entire planet and its resources. In the
interests of the community, Betamotor wants its customers and technical assistance staff
to be aware of the need to adopt procedures for the use of the vehicle and for disposal
of its parts which fully comply with the applicable regulations in terms of environmental
pollution and the disposal and recycling of waste.
SAFETY
Carbon monoxide
• Exhaust gases contain carbon monoxide (CO), which is a poisonous gas. Carbon monoxide can cause loss of consciousness and lead to death.
• If the engine has to be started, make sure that the area is well ventilated. Never start the
engine in an enclosed space.
• Starting the engine in an enclosed space is permissible only if appropriate devices are
used for extracting the exhaust gases.
betamotor.com
INTRODUCTION
Petrol
• Petrol is highly flammable and in certain conditions can cause explosions.
• Keep heat sources, sparks and flames well away from the work area.
• Always work in a well-ventilated area.
• Never use petrol as a cleaning solvent. In general, avoid handling it if not strictly necessary.
• Do not use petrol for cleaning components by means of compressed air.
• Keep it well out of the reach of children.
Engine oil
• Engine oil can cause skin diseases if it repeatedly comes into contact with the skin for
prolonged periods.
• If you come into contact with engine oil, wash the affected parts as soon as possible
with soap and water.
• If it comes into contact with the eyes, rinse with plenty of water and consult a doctor.
• If ingested, do not provoke vomiting, in order to avoid inhalation of the product. Consult
a doctor immediately. If it is thought that inhalation of the product has taken place, take
the person concerned urgently to hospital.
• Waste oil contains dangerous substances which are harmful to the environment. When
changing the oil, it is necessary to be equipped for disposing of the waste oil in accordance with the relevant law.
• Do not dispose of waste oil into the environment.
• Keep it well out of the reach of children.
Coolant
• In certain circumstances the ethylene glycol in coolant is flammable, and its flame is
invisible. If ethylene glycol catches fire, the flame, although invisible, can cause serious
burns.
• Avoid bringing coolant into contact with hot components. Such components could be
sufficiently hot to cause it to ignite.
• Coolant (ethylene glycol) can cause skin irritation and is poisonous if ingested.
• If coolant comes into contact with the skin, remove any contaminated clothing or footwear immediately and wash promptly with soap and water. If it comes into contact with
the eyes, rinse with plenty of clean water and consult a doctor immediately. If ingested,
do not provoke vomiting, in order to avoid inhalation of the product. Give the affected
person clean water to drink, take them to hospital urgently and show the product to the
medical staff.
betamotor.com
INTRODUCTION
• In case of exposure to high concentrations of fumes, take the affected person into an
unpolluted environment and if necessary call a doctor.
• Do not remove the radiator filler cap when the engine is still hot. The coolant, being
under pressure, can spurt out violently and cause burns.
• Coolant contains dangerous substances which are harmful to the environment. When
changing the coolant, it is necessary to be equipped for disposing of waste oil/coolant
in accordance with the applicable law.
• Do not dispose of coolant into the environment.
• Keep it well out of the reach of children.
Hot parts
• The engine and exhaust system become very hot and retain heat for a considerable
time, even after the engine has been switched off. Wait for them to cool down before
handling these parts or working in areas adjacent to them. In addition, use insulating
gloves.
WARNINGS
The information in this paragraph is important in order for the operations carried out on
the motorcycle to be performed without damaging the motorcycle itself.
• Before dismantling, clean the vehicle thoroughly.
• During dismantling, clean all parts and put them away in containers, following exactly
the order of dismantling.
• Always use special tools where necessary and whenever their use is specified.
• Always use adhesives, sealants and lubricants where specified. Follow the recommendations regarding their technical characteristics.
• Always replace parts such as gaskets, O-rings and safety washers with brand new
parts.
• When loosening or tightening nuts or bolts, always start with the largest or from the
centre. Always follow the recommended torque settings.
• Use only original Betamotor spare parts.
betamotor.com
INTRODUCTION
Assembly
Valvegear group
Valve adjuster covers
Camshaft sprocket
Water pump cover
Carburettor flange
Exhaust flange
Bush, movable guide
Camchain tensioner
Water circuit bleed screw
Water circuit drain screw
Rocker spindle plug
Valve adjuster locknut
Cylinder head cover
Head – Cylinder
Crankshaft group
Crankshaft half, clutch side
Crankshaft half, flywheel side
TDC locking bolt
Crankcase group
RH crankcase – LH crankcase
RH crankcase – Clutch casing
Selector drum bearing retaining bolt
Flywheel cover
Clutch cover
Head – Cylinder – Crankcase
Oil drainplug
Oil filler plug
Oil level plug
Retaining plate Corteco
Oil circuit jet
Ignition/Starting group
Pickup retaining bolt
Stator retaining screw
Ramp
Kickstart pivot retaining bolt
Sparkplug
Gearchange group
Detent cam
Oil pump group
Cover, oil pump LH
Cover, oil pump RH
betamotor.com
Component
Qty
Thread lock
Torque (Nm)
Bolt M6x16
Screw M6x10
Screw M6x20
Bolt M6x16
Screw M6x15
Screw M6x25
Bolt M6x16
Screw M6x12
Screw M6x12
M16x1
Nut M6x0.75
Bolt M6x35
Bolt M6x25
Bolt M6x55
Bolt M6x25
4
2
3
2
4
1
2
1
1
2
4
4
2
4
1
10
10
10
10
10
10
8
8
8
10
11
10
10
10
10
Nut M18x1.5
1
150
Nut M14x1.5
Special bolt M8
1
1
120
25
Bolt M6x45
Bolt M6x60
Bolt M6x25
Bolt M6x40
Bolt M6x30
Bolt M6x10
Bolt M6x30
Bolt M6x35
Screw M6x20
Stud M10x1.25
Nut M10x1.25
M16x1.25
M16x1.25
M16x1.5
Special screw M4x8
M5x0.75
2
9
8
1
1
2
5
2
4
4
4
1
1
1
2
2
10
10
10
10
10
10
10
10
10
30
30
20
10
10
3
6
Bolt M6x12
Screw M5x25
Bolt M6x20
Bolt M8x20
M10x1
2
3
2
1
1
Bolt M6x35
1
Screw M6x14
Screw M6x20
Screw M6x15
2
1
1
X
X
X
X
8
6
8
25
10-12
X
10
X
10
10
10
INTRODUCTION
Assembly
Component
Qty
Thread lock
Torque (Nm)
Pivot, oil pump idler gear
Intake filter cover, output oil pump
Screw, shallow, M6x25
M20x1.5
1
1
X
10
15
Intake filter cover, scavenge oil pump
Filter cover, output oil pump
M20x1.5
Screw M6x20
1
3
15
10
Oil pressure relief valve
Clutch group
Special bolt M12x1.25
1
20
Pressure plate
Clutch centre
Bolt M6x16
Special nut M14x1.25
6
1
10
90
Clutch actuator body.
Frame – Engine
Bolt M6x16
3
10
Swing-arm bolt
Stay RH
Nut M16
Bolt M8
1
2
90
25
Stay LH
Engine mounting bolt, front
Bolt M8
Bolt M10
2
1
25
25
Engine mounting bolt, lower
Mounting bolt, cylinder head
Nut M10
Nut M8
1
1
25
30
01.00040.000
Flywheel extractor
01.00041.000
Key for water pump shaft
01.00042.000
Crankcase splitter
01.00043.000
Valve spring fitting tool
01.00044.000
Inner clutch hub locking tool
01.00045.000
Carburettor adjusting
spanner
betamotor.com
LUBRICATION CIRCUIT
1 LUBRICATION CIRCUIT
9
8
12
5
7
3
6
2
1
The output oil pump (1) draws in oil from the area
at the base of the gearbox through its own mesh oil
filter (2) and then sends it to the paper oil filter (3).
From here the oil, starting from the bypass valve (4),
is directed in three different directions: by means of
a jet (5) it lubricates the piston pin and takes heat
from the crown of the piston; and it passes through
two pipes, one of which (6) takes it to the crankshaft to lubricate the roller bearing on the crankpin;
the other (7), whose flow is regulated by a jet (8),
feeds the valvegear (9). The oil then returns to the
base of the crank chamber from the piston, the conrod assembly and the cylinder walls, and is drawn
in by the scavenge pump (10) through the mesh
filter (11). It is pumped through special jets (12)
and lubricates the transmission gears. The oil in the
cylinder head, however, returns to the base of the
gearbox passing through the timing case and the
inner clutch casing.
8
12
1.1 ENGINE OIL
11
4
10
betamotor.com
Use only fully synthetic oils of a reputable brand
(BARDAHL XTC60 15W50).
LUBRICATION CIRCUIT
1.2 CHECKING THE ENGINE OIL LEVEL
The engine oil level must be checked when the engine is warm. Run the engine for several minutes
and then switch it off. Place the bike on a flat surface in such a way that it is perfectly vertical.
MAX
MIN
Wait a few minutes and then check the oil level in
the sightglass located in the clutch casing (righthand side of the engine). The level must be between the limits indicated in the picture.
If necessary, remove the oil filler plug and top up
the level.
N.B. Running the engine with too little oil causes excessive wear to the engine components.
1.3 CHANGING THE ENGINE OIL
N.B. At each oil change, the mesh filters must be
cleaned and the paper filter replaced.
N.B. The oil change must be carried out when the
engine is at working temperature. Be careful not to
scald yourself with the hot oil.
After the engine has reached operating temperature, switch the bike off and stand it upright.
Unscrew the oil drainplug and let all the oil flow out
into a drain pan. Thoroughly clean the magnet on
the drainplug to get rid of the metallic impurities
that it has collected.
betamotor.com
LUBRICATION CIRCUIT
Unscrew the plug in the left-hand casing and use
pliers to extract the filter. Clean it carefully and blow
it through with compressed air. Check for damage
to the O-rings, and replace them if necessary. Refit
all the parts and tighten the plug to 15 Nm.
Carry out the same procedure for the output mesh
filter, for which the access is via the right-hand engine casing.
betamotor.com
LUBRICATION CIRCUIT
Position a container under the bike, near the cover
for the paper filter, and unscrew the bolts on the
filter cover.
Then extract the paper filter using pliers. Check the
condition of the O-ring too, and replace it if necessary.
Change the filter and refit the cover, tightening the
three M6x20 bolts to 10 Nm.
Refit the oil drainplug, tightening it to 20 Nm, and
refill with 0.81 of engine oil (BARDHAL XTC60
15W50).
N.B. If the engine has been opened up for an internal
inspection, the quantity of oil to put in is 0.9 litres.
A
Finally, tighten the oil filler plug (A) to 10 Nm.
betamotor.com
ENGINE REMOVAL AND REFITTING
2 ENGINE REMOVAL AND REFITTING
2.1 ENGINE REMOVAL
Thoroughly clean the entire motorcycle and put it
on a stable stand.
Remove the rear mudguard.
Unhook the tension spring (A) on the side of the
exhaust system and the two springs in front of the
cylinder head (B).
Next, remove the exhaust manifold(C) by pulling it
forwards.
A
Remove the plate under the engine.
B
B
C
10
betamotor.com
ENGINE REMOVAL AND REFITTING
Disconnect all the electrical cables located between
the headstock and the fuel tank under the plastic
tank cover:
1A connector, control unit to generator cable group
1B control unit connector
2A connector, regulator to wiring harness (regulated
voltage)
2B regulator connector (regulated voltage)
3A connector, regulator to flywheel (alternating current)
3B regulator connector (alternating current)
4A connector, killswitch cable to generator
4B connector, killswitch cable to vehicle wiring harness
2A
4A
3B
4B
1B
2B
1A
5A connector, electric fan to vehicle wiring harness
5B electric fan connector
6A thermoswitch connector
6B connector, thermoswitch to vehicle wiring harness
3A
5A
6B
5B
6A
Disconnect the hot start cylinder (A) from the carburettor flange (B) by loosening the clamp (C) and
pulling off the pipe (D) which connects it to the carburettor flange.
B
C
D
A
11
betamotor.com
ENGINE REMOVAL AND REFITTING
Close the tap on the fuel tank by screwing in the
relevant knob.
Disconnect the pipes and the electrical connector
from the electric tap (A), after making sure that the
supplementary/reserve tap (B) is closed (pull the
knob downwards).
B
A
Disconnect the oil vapour breather pipe.
12
betamotor.com
ENGINE REMOVAL AND REFITTING
Loosen the clamp which secures the carburettor to
the rubber carburettor flange.
Loosen the clamp (A) which secures the rubber
sleeve to the filter box and pull the carburettor
backwards (see the arrow in the illustration) until
the carburettor is completely disconnected from the
rubber flange.
A
Remove the sprocket cover casing by unscrewing
the two retaining bolts (A).
Slip the chain off the sprocket after slacking off the
rear wheel spindle.
Remove the clutch actuator by unscrewing the three
retaining bolts (B).
B
B
B
A
A
13
betamotor.com
ENGINE REMOVAL AND REFITTING
Position a drain pan under the engine and unscrew
the drain bolt for the cooling system (A). Then open
the radiator cap (B) to allow all the liquid in the
system to flow out.
A
Loosen the clamps that secure the cooling system
pipes respectively to the cylinder (A) and the water
pump (B).
B
Pull off the sparkplug cap and unscrew the upper
bolt (A) securing the coil support.
A
14
betamotor.com
ENGINE REMOVAL AND REFITTING
B
Loosen the clamps that secure the cooling system
pipes respectively to the cylinder (A) and the water
pump (B).
A
Unscrew the bolts that secure the stay to the frame
(A) and take out the front engine mounting bolt (B)
after unscrewing it.
A
A
B
15
betamotor.com
ENGINE REMOVAL AND REFITTING
Unscrew the bolt securing the radiator and then
remove the entire radiator/stay assembly after disconnecting the connectors for the electric fan and
the radiator sensor.
Take out the bolt securing the cylinder head to the
frame.
Slack off the nut securing the lower engine/frame
mounting bolt.
16
betamotor.com
ENGINE REMOVAL AND REFITTING
Remove the swing-arm bolt (A) and pull the swingarm backwards.
Take out the lower engine mounting bolt (B) and
then lift the engine from the frame.
A
B
2.2 REFITTING THE ENGINE
To refit the engine, follow the engine removal steps
in reverse. For tightening torques, consult the relevant table.
Once refitting is complete, refill the system with
coolant through the radiator until the liquid comes
out of the bleed hole on the left-hand side of the
cylinder head.
Tighten the bleed screw and continue pouring the
liquid into the radiator until it reaches the flared section in proximity to the filler cap. The total quantity
of liquid to put in is 0.6 litres.
Caution
Do not run the engine with the voltage regulator connected to the electrical generator without also connecting the vehicle wiring harness (central system).
Doing so could cause damage to the regulator itself.
17
betamotor.com
DISMANTLING
Before you start to dismantle the engine it is essential that you also read the next chapter, which deals
with assembly, because it discusses all the checks
that need to be carried out on individual components.
3.1 DRAINING THE OIL
Remove the oil drainplug and let the oil flow out
into a drain pan.
Take out the oil filters from the left-hand (1) and
right-hand (2) crankcase halves after first removing
the filter covers.
1
2
18
betamotor.com
DISMANTLING
3.2 IGNITION
Undo the 7 bolts retaining the flywheel cover and
remove it, together with the stator and pickup that
are mounted on it.
3.3 CYLINDER HEAD
Remove the washer from the TDC bolt and look
for TDC between the compression and combustion
strokes. At this point, all the valves are fully closed
and the complete timing system is therefore unloaded.
To find TDC, set up a dial gauge with suitable support in the sparkplug hole, and rotate the flywheel
by hand until the dial gauge indicates that the piston has reached its highest point.
Then tighten the crankshaft locking bolt without the
washer and check that the crank is locked by trying
to rotate the flywheel.
Remove the sprocket from the output end of the
layshaft after first removing the retaining circlip, and
then remove the further circlip located behind the
sprocket.
19
betamotor.com
DISMANTLING
Remove the valve covers and then take out all the
bolts securing the cylinder head cover: 2 M6x25
bolts (A), 4 M6x55 bolts (B) and 4 M6x35 bolts (C).
B
A
C
Remove the head cover and then the camshaft end
plug. If this operation is difficult, it should be carried
out with the aid of a rubber hammer by tapping on
the fins on the left-hand side of the engine to help
in detaching the cover from the head. If you need
to inspect the rockers, unscrew the rocker spindle
housing plugs and extract the spindles using an M4
bolt screwed into the spindles from the timing case
side. Do this while the cover is still fitted to the head
and secured by the bolts. This is because the spindles are restrained from rotating, which helps when
screwing in the extracting bolt.
Before you undertake the removal of the camshaft,
attend to the water pump. This is because the camchain tends to lock the water pump gear, which
helps when removing the water pump shaft.
After you have removed the water pump cover and
its retaining bolts, remove the circlip which retains
the impeller, and then the impeller itself. Then use
the special tool (A) to unscrew the water pump
shaft from the gear which takes its drive from the
camchain.
A
20
betamotor.com
DISMANTLING
Remove the camchain tensioner by unscrewing the
two retaining bolts.
Remove the camshaft and its bearings from the
head, taking care not to let the camchain fall into
the timing case. For camshaft inspection and dismantling, refer to what is said in the chapter on assembly.
Remove the water pump shaft, taking care that the
gear does not fall into the crankcase. Remove the
fixed camchain guide.
Unscrew the cylinder head retaining nuts, which are
screwed onto the studs, and the bolt on the water
pump side. Then remove the head and the head
gasket, taking care also to remove the dowels.
If the water pump shaft bearings are to be replaced,
extract the one on the outer side by pressing it with
a padded drift towards the inside of the timing case
until it comes completely free.
For the inner bearing, use a slide hammer with a
suitable internal extractor.
21
betamotor.com
DISMANTLING
3.4 CYLINDER
Slide the cylinder up until the piston pin is visible.
Then remove the retaining circlip and extract the
piston pin as far as is necessary to release the connecting rod.
In this way, you can take off the cylinder and piston together without having to split them. You only
need to split them when performing operations or
measurements on the two components individually
(see the section devoted to this subject in the chapter on assembly).
3.5 FLYWHEEL
Unscrew the flywheel retaining nut (A) and extract
the flywheel using the special extractor (B). Screw
the extractor into the threads in the flywheel and
extract it by tightening the central bolt which bears
on the crankshaft.
A
22
betamotor.com
DISMANTLING
B
3.6 OIL PUMP (LEFT-HAND CRANKCASE)
1
Remove the left-hand oil pump cover (2) after first
_unscrewing the retaining screws (1). Next, extract
the pump outer rotor (4) using a pair of circlip pliers, after you have removed the pin (3). Then remove the inner rotor (5) and the O-ring (6) which
seals the cover.
2
1
4
6
5
3
23
betamotor.com
DISMANTLING
3
1
3.7 CLUTCH
3
3
1
3
2
2
3
1
3
3
3
3
1
Unscrew the bolts retaining the clutch cover (1) and
the oil filter cover (2) and remove the two covers
and their O-rings. Then unscrew the bolts holding
the clutch casing (3) after you have removed the
kickstart lever.
2
3
Unscrew the bolts (1) retaining the clutch springs
(3) in diagonal sequence to prevent the friction
plates (8) from jamming when the springs are released.
24
betamotor.com
DISMANTLING
2
1
4
Then extract, in sequence, the special washers (2),
the springs (3) and the clutch pressure plate (4).
Next, remove the friction plates (8) and then the
pressure plate lifter (7), the needle roller bearing
(6) and the corresponding washer (5).
7
Using a screwdriver, release the tabs on the
tabwasher (10).
25
betamotor.com
DISMANTLING
Which locks the retaining nut (9) for the clutch hub
(11) and unscrew the nut, using the special tool for
locking the clutch centre.
Extract the clutch centre (11), the thrust washer
(12), the clutch basket (13), the bush (14) and the
thrust washer (15).
3.8 PRIMARY TRANSMISSION
Unscrew the crankshaft nut (1) and extract the primary transmission gear (2).
Also remove the washer located between these two
components.
1
2
26
betamotor.com
DISMANTLING
3.9 KICKSTART
Extract the kickstart shaft complete (1) together
with the thrust washer (2), ensuring that the assembly does not come apart accidentally.
N.B. Take care when extracting the kickstart return
spring from its housing. Because it is under preload,
it can cause injury as a result of rapidly springing
back to its rest position.
Remove the kickstart idler gear (5) after you have
first removed the retaining circlip (3). At the same
time, remove the two thrust washers (4, 6) located
either side of it on the idler shaft.
Remove the kickstart ramp (8) after you have released it by taking out the retaining bolts (7).
N.B. To facilitate removal of the ramp, heat it to soften the thread lock on the two retaining bolts..
3.10 SHIFTING MECHANISM
27
betamotor.com
DISMANTLING
Take out the gearchange shaft (1), pushing back the
movable pawl with a screwdriver to prevent it from
interfering with the gearchange detent cam.
Pull off the idler gear (5) together with its thrust
washer (4), after you have first removed the retaining circlip (3).
Unscrew the bolt (6) securing the detent cam (7)
and remove the cam, moving the detent lever
aside.
Unscrew the retaining bolt (8) and extract first the
idler pivot pin (9) and then the detent lever (10).
3.11 OIL PUMP (RIGHT-HAND CRANKCASE)
Extract the oil pump gear (2), after you have first
removed the retaining circlip (1).
3
28
betamotor.com
Remove the pin (3) which carries the drive from
the gear (2) to the oil pump shaft (8), and then the
thrust washer (4). Remove the oil pump cover (7)
after first unscrewing the retaining screws (5, 6).
Extract the oil pump shaft (8) together with the
pin (9), and then remove the oil pump rotors (10),
adopting the same procedure as was used for the
oil pump in the left-hand crankcase half.
DISMANTLING
3.12 TIMING SPROCKET
Once you have removed the camchain, take out the
movable guide (3) and the bush (2) by unscrewing
the retaining bolt (1).
Use an engineering chisel to remove the woodruff
key (4) from its housing in the clutch side crankshaft end, and then extract the timing gear (5).
4
3.13 SPLITTING THE CRANKCASE
Remove the ball and the clutch pushrod.
Unscrew all 11 bolts that hold the crankcase
together.
29
betamotor.com
DISMANTLING
Once you have removed the gasket from the cylinder
base, use the special tool for splitting the crankcase,
securing it to the left-hand crankcase half using the
threads for the flywheel cover retaining bolts. Turn
the engine so that the right-hand crankcase half is
facing downwards.
Then screw in the bolt at the end of the special tool
until the two crankcase halves are separated, and
manually take off the left-hand crankcase half.
3.14 GEARBOX AND SHIFTING MECHANISM
Extract the selector fork spindles (1) and the gearbox selector drum (2).
1
2
30
betamotor.com
1
DISMANTLING
Remove the selector forks (3) and then extract the
mainshaft and layshaft as a unit, complete with all
the gears.
3
3
3
3.15 CRANKSHAFT
Attach the pad (A) (supplied with the crankcase
splitter) to the crankshaft end on the clutch side,
so that the crankshaft extractor (which is the same
tool as the crankcase splitter) has a flat surface to
push against.
A
Fit the splitting tool to the right-hand crankcase half,
using the threads for the clutch casing bolts to retain it. Then screw in the bolt at the end of the special tool until the crankshaft is extracted.
If the bearings need to be replaced, heat the crankcase to 150°C. The bearings will be easy to extract
at this temperature.
31
betamotor.com
ASSEMBLY
4.1 RIGHT-HAND CRANKCASE
2
8
7
3
1
5
4
Heat the crankcase in an oven to 150c°. Fit the ball
bearings into their housings (main bearing 1, mainshaft bearing 2, layshaft bearing 3, gear selector
drum bearing 4), and drive them home with a press
and suitable mandrels, taking care that the crankcase is resting on a flat surface throughout. The
housing for the needle roller bearing (gearchange
shaft 5), does not have a stop: it can be located
flush with either surface of the crankcase half.
If after the crankcase has cooled down, the outer
race of one of the bearings tends to spin in its housing, the crankcase itself must be replaced.
N.B. Before refitting the bearings, check the state of
wear of the revolving parts and make sure that the
balls run correctly in their tracks in the bearing.
6
8
While the crankcase is still hot, use a press to fit
the shaft (6) for the kickstart idler gear on the righthand side.
Fit the breather nozzle (7), applying mediumstrength thread lock to the threads.
Fit the oil jets (8) and secure the selector drum
bearing (4) with its retaining bolts (9), applying
medium-strength thread lock tightening these to 10
Nm.
9
9
32
betamotor.com
ASSEMBLY
Fit the oil expansion plug (10), driving it home with
a suitable pin punch, after having checked that the
oilways are not blocked by blowing them through
with compressed air.
Threadlocker Blue
Make sure that the oil pump housing is free from
scoring and signs of seizure.
Fit the oil pressure relief valve (11).
N.B. Make sure that the number and thickness of
washers (12x18x1, 12x18x1.5) for the oil pressure
relief valve are the same as in the factory setup.
Fit the crankshaft oilseal (12), lubricating its outer
surface with grease to make it easier to insert it into
its housing. Press it in until it is flush, with the open
side facing inwards.
N.B. Remember to always grease the outer surface of
oilseals to help seat them properly in their housings.
33
betamotor.com
ASSEMBLY
4.2 LEFT-HAND CRANKCASE
2
Fit the bearings (main bearing 1, mainshaft bearing
2, layshaft bearing 3, gearchange shaft needle roller
bearing 4), following the same procedure as for the
right-hand crankcase.
1
3
N.B. When fitting the main bearing, use a pad on
the opposite side to avoid putting excessive stress on
the flat surface of the housing under the load from
the press.
4
Fit the oilseals for the crankshaft (5), layshaft (6)
and gearchange shaft (7), all with the open side facing inwards. Remember to grease the outer surface
to facilitate seating.
6
5
7
Fit the oilway expansion plug, driving it home with
a suitable pin punch.
34
betamotor.com
ASSEMBLY
Make sure that the oil pump housing is free from
scoring and signs of seizure.
Blow compressed air through all the oilways to clean
them, and check that there are no obstructions.
N.B. Before refitting the bearings, check the state of
wear of the revolving parts and make sure that the
balls run correctly in their tracks in the bearing.
4.3 CLUTCH CASING
Fit the kickstart oilseal (1) in its housing with the
open side facing inwards, making sure that it goes
fully home.
Threadlocker Blue
1
35
betamotor.com
ASSEMBLY
Fit the crankshaft oilseal (2) in its housing, with
the open side facing inwards. Remember to grease
the outer surface to facilitate seating. Then secure
the oilseal with its retaining plate and tighten the
screws to a torque of 3 Nm, after applying mediumstrength thread lock.
Fit the oil filter spigot (3) with its O-ring.
3
N.B. The spigot is an interference fit in its housing.
2
4
4
36
betamotor.com
Close the oilways with the special oilway expansion
plugs (4), using a pin punch.
Make sure that the oilway is clear by blowing it
through with compressed air.
Fit the oil level plug (5), tightening it to 10 Nm.
ASSEMBLY
4.4 GEARBOX AND SHIFTING MECHANISM
Before proceeding to the reassembly of the gearbox mainshaft and layshaft, carry out the following
inspections:
- Check the wear on the sliding surfaces of the
mainshaft and layshaft.
- Check that the teeth of the gears do not show
signs of pitting or particular wear (A).
- Check that the dogs on the gears are not rounded
off (B).
- Check for wear on the grooves for the selector
forks (C).
- Check that all the parts slide correctly.
N.B. During the process of reassembly, clean and oil
all the parts with suitable engine oil.
N.B. It is good practice to fit new circlips each time
the gearbox is assembled.
4.4.1 Mainshaft
Position the shaft (1) with the splined end facing
downwards and fit the following parts onto it from
above, in the following order:
- 5th idler gear (2), with the dogs facing upwards,
followed by the relative splined washer (3). Secure with the circlip (4). The latter must be fitted
such that the side which does not have the corner radius faces upwards.
- Double sliding 2nd/3rd gear (5) with the larger gear facing downwards, and thrust washer
17x20.5x1 (6).
- 4th idler gear (7) with housings for the dogs facing downwards, spacer (8) and 15x25x1 thrust
washer (9).
N.B. Check that the gears slide correctly.
N.B. Apply molycote grease between shaft and
gears.
37
betamotor.com
ASSEMBLY
A
B
4.4.2 layshaft
Position the shaft (1) with the splined end facing
downwards after fitting the 20x27x1 washer (2)
and the spacer (3), securing them so that they cannot fall off while the other parts are being fitted.
Then fit the parts from above in the following order:
- Sliding 4th gear (4), with the dogs facing upwards,
and 22.2x29x1 thrust washer (5).
- Bush (6), 2nd idler gear (7) with the flat side
facing downwards, splined washer (8) and stop
washer (9) with the tangs facing downwards.
- Splined bush (10), 3rd idler gear (11) with the flat
side facing upwards, splined washer (8), circlip
(12).
- Sliding 5th gear (13), with the groove for the selector fork facing downwards, 17x24x0.5 thrust
washer (14).
- Bush (15), 1st idler gear (16), with the more concave side facing downwards.
N.B. Check that the gears slide correctly.
N.B. Apply molycote grease between shaft and
gears.
Fit mainshaft (A) and layshaft (B) as a pair into their
respective bearings in the right-hand crankcase.
Check the state of wear of the contact areas between the selector forks and the grooves in which
they run in the gears (A), and between the pegs and
the grooves in the selector drum (B).
Fit the pegs (2) to the selector forks (1), using
grease.
38
betamotor.com
ASSEMBLY
Fit the complete selector forks into the gearbox, positioning them in their guides in the gears.
Check the wear on the guides in the selector drum.
Locate the drum in its bearing and locate the pegs
in the guides. Push the two pins through the forks,
taking care to use the longer one for the forks on
the secondary shaft.
N.B. Before fitting the fork spindles, make sure that
the forks slide freely on them and check the spindles
for wear.
N.B. Always remember to oil the various parts in contact with each other (pegs/selector drum grooves,
selector forks/gears, etc.).
N.B. Turn the two gearshafts over by hand to make
sure that everything moves correctly.
39
betamotor.com
ASSEMBLY
4.5 CRANK ASSEMBLY
A
If the crankshaft has been dismantled for the purpose of replacing the connecting rod or inspecting
the state of wear of the roller cage and the crankpin,
be careful during subsequent reassembly that the
oilway holes in the crankpin (A) and in the clutch
side crankshaft half (B) are properly lined up. Faulty
assembly could lead to lack of proper lubrication
in the area of the conrod big-end, with consequent
damage to the roller bearing.
B
1
1
Check for misalignment of the shafts in the crankshaft halves by setting up the crankshaft between
centres, or in a similar instrument, and using a pair
of dial gauges (1) positioned on the contact surfaces
for the main bearings (2) to measure the maximum
variation during a complete revolution of the crank.
The limit value is 0.08mm.
If a variable difference is found between the point
measurements of the two crankshaft halves, this
may be due a twist in the crankshaft itself.
The limit value for this difference is 0.03mm.
2
2
You also need to check the side-float at the conrod
big-end, whose value must be within the following
range:
Recommended clearance: 0.15-0.35mm
Maximum clearance: 0.50mm
40
betamotor.com
ASSEMBLY
4.6 CLOSING THE CRANKCASE
Heat the main bearing in the right-hand crankcase
half so as to facilitate insertion of the crankshaft.
Fit the spacer (1) onto the crankshaft and the dowels into their housings (2).
1
2
2
Grease the area of the crankshaft which needs to
slide into the oilseal in the left-hand crankcase (1),
and fit the crankcase centre gasket, cutting it in the
cylinder area (2) to avoid interference with the connecting rod during assembly.
N.B. Put a little grease on the gasket face of the righthand crankcase in order to help the gasket to adhere.
N.B. It is good practice to change the gaskets each
time the crankcase is opened.
2
1
After heating the left-hand main bearing, place the
left crankcase half over the right half, and use a plastic hammer to close up the two halves until they are
positioned correctly.
41
betamotor.com
ASSEMBLY
Rotate the mainshaft and the layshaft by hand to
verify that the gearbox moves correctly and that all
the gearbox components slide freely.
N.B. Check that the gearbox layshaft oilseal is correctly positioned after the crankcase is closed up.
Insert the bolts in the positions shown in the drawing and tighten them to 10 Nm.
Accurately cut the protruding part of the cylinder
base gasket, taking care not to damage the surface
on which the cylinder will rest.
Tap the two ends of the crankshaft several times in
an axial direction with a rubber hammer in order
to release it from residual stresses induced in the
crankcase by heating it.
4.7 SHIFTING MECHANISM
To assemble the shifting shaft, follow these steps:
- Clamp the shaft (1) with the serrated end facing
upwards.
- Fit the movable pawl (2) with the pin facing
downwards, and insert the pin into the corresponding slot in the fixed pawl.
- Position the spring (3) with one end in the housing in the shaft (A) and the other on the tang (B)
on the movable pawl.
- Fit the spring guide (4) and the return spring (5),
hooking it onto the pin on the fixed pawl (D) by
means of its two ends (C).
42
betamotor.com
ASSEMBLY
After you have fitted the gearchange shaft, check
the axial play between the two pawls, which must
be between 0.50mm and 0.70mm. If this clearance
is exceeded, replace the movable pawl.
Position the spring (1) and the detent lever (2)
in their housing and hold them in place with the
idler pivot pin (3). Secure with the M6x25 bolt (4)
tightened to 10 Nm after applying medium-strength
thread lock.
Threadlocker Blue
Move the detent lever out of the way and fit the
detent cam (5). Secure with the M6x35 bolt (6)
tightened to 10 Nm after applying medium-strength
thread lock.
5
2
43
betamotor.com
ASSEMBLY
Fit the shifting shaft into its roller bearings after
oiling it well, and push back the movable pawl so
that it can take up its correct position against the
detent cam, and so that the gearchange shaft goes
fully home. Before assembling these parts, fit the
14x30x1 thrust washer onto the shaft. Locate the
shaft in such a way that the ends of the spring (A)
sit either side of the lug (B) on the crankcase.
Fit the shifting lever and test the gearbox operation
by rotating the mainshaft by hand and changing
from one gear to another.
4.8 TIMING SPROCKET
Threadlocker Blue
3
5
4
44
betamotor.com
1
Fit the timing sprocket (1) after you have applied
a sufficient amount of grease to the outer surface
that comes into contact with the oilseal. Lock the
sprocket with the Woodruff key (2), tapping it several times if necessary with a rubber hammer to help
it to seat properly.
Fit the movable camchain guide (3) with its bush
(4) and secure with the M6x25 screw (5), after applying medium-strength thread lock. Tighten to 10
Nm.
Fit the camchain, running it round the sprocket and
passing it through the slot in the timing case.
ASSEMBLY
4.9 OIL PUMPS
N.B. The pumps have reference marks both on the
outer rotor (A) and on the inner rotor (B). During assembly these two marks must remain on the same
side of the pump and must always face towards the
inside of the pump housing.
Position the engine bottom end with
the outer side of the right-hand crankcase half facing upwards. Locate the
pump (1) in its housing in the right
half of the crankcase, after oiling it
well, with the reference marks facing
towards the inside, so that they are
not visible once the pump is fitted.
Insert the shaft (2) with the part with
the two holes facing upwards, fitting
the pin (3) into the second hole from
the top.
Use a feeler gauge to check the clearance between
inner rotor and outer rotor. If you find that there
is play beyond the permitted limits, replace the
pump.
Maximum clearance 0.20mm.
45
betamotor.com
ASSEMBLY
Measure the clearance between the outer rotor and
the pump housing, using a feeler gauge for this
too.
Standard clearance 0.09-0.23mm.
Measure the axial clearance, defined as the difference between the depth of the pump housing in
the crankcase and the thickness of the outer rotor.
Standard clearance 0.05-0.10mm.
Refit the cover (4), after you have blocked the hole
with the oilway expansion plug (5), and tighten
the M6x20 screws (6) and M6x15 screws (7) to 10
Nm.
After you have fitted the washer (8) and the pin
(9) into the top hole in the shaft (2), secure the
drive gear (10) with the circlip (11). Ensure that the
gear is positioned correctly: the side with the larger
raised part must face downwards.
Rotate the gear (10) by hand and check that the
pump moves without being forced.
Position the engine bottom end with the left half
of the crankcase facing upwards, and fit the pump
(12) after oiling it well.
Insert the pin (13) and perform a clearance check
as for the pump in the left-hand half.
Fit the O-ring (14) into its seat and refit the cover
(15) to the pump.
Tighten the M6x14 screws (16) to 10 Nm.
Rotate the gear (10) by hand and check again that
it moves properly.
14
46
betamotor.com
ASSEMBLY
Insert the two filters (17) into their holes, after first
lubricating them with oil and fitting the O-rings
(18).
17
N.B. The two filters have a tapering internal cavity.
Use a pin punch with a taper point to facilitate fitting.
Refit the filter covers (20), tightened to a torque of
10 Nm, after fitting the O-rings (19). Also close the
oil drain hole with the drainplug (21) and 16x22.5x1
gasket, tightening it to 20 Nm.
21
20
47
betamotor.com
ASSEMBLY
Threadlocker Blue
4.10 KICKSTART
4.10.1 Preassembly of kickstart shaft
Clamp the kickstart shaft (2) with the serrated end
facing downwards and fit the kickstart sleeve (3)
from above, applying molycote grease to the splined
section.
Fit the spring (4) and the 20x30x0.5 thrust washer
(5), securing them with the circlip (6).
N.B. Take care that the sleeve is fitted in such a way
that the relative position of the hole (A) for securing
the return spring (11) is as shown in the drawing.
A
Position the kickstart shaft (2) with the serrated end
facing upwards, and fit the thrust washer 16x25x0.5
(7), the caged roller bearing (8), the gear (9) with
the side ratchet side facing downwards, and the
16x25x0.5 thrust washer (10).
Fit the return spring (11), securing the end in the
hole provided (A), and fit the spacer with the recess
for the spring facing downwards.
Fit the ramp (14) with two M6x20 bolts. Tighten the
bolts to 8 Nm after first applying thread lock to the
threads.
48
betamotor.com
CAP 4_OK ENG.indd 48
9-02-2007 17:06:56
ASSEMBLY
4.10.2 assembling the kickstart
Insert the kickstart shaft (1) into its housing after
first oiling it well and fitting the 16x25x0.5 thrust
washer (13) onto it, taking care that the spring is
secured in the hole provided for it (B).
B
N.B. Apply some molycote grease to the contact surfaces between the ramp and the kickstart sleeve.
Fit the kickstart lever to check that the parts move
freely.
Fit the kickstart idler gear (17) on its shaft, together
with the two 18x27x0.5 thrust washers (16, 18),
after you have lubricated the parts in contact with
each other, and secure it with the circlip (19). Ensure that the convex side of the gear is facing towards the crankcase.
Check that the parts move correctly with respect to
each other.
N.B. Before you assemble the various parts, check
the wear on the gear teeth and on the contact surfaces between the ramp (14) and the kickstart sleeve
(3). In the event of excessive wear, replace the damaged components.
4.11 PRIMARY TRANSMISSION GEAR
49
betamotor.com
ASSEMBLY
Fit the idler gear (1) on its pivot pin with the concave side facing outwards, fit the special 11x17x0.5
washer (2), and secure with the circlip (3).
Fit the primary transmission gear (4) with the convex
side facing inwards, taking care to align the keyway
with the woodruff key itself. Position the 18x30x3
washer (5).
Lock the crankshaft at TDC using the appropriate
bolt (7), then tighten the nut (6) to 150 Nm.
1
N.B. Check the wear on the gear teeth before carrying on with assembly, and oil well all the parts that
are in contact with each other.
4
4.12 CLUTCH
Fit the 20x32x2 washer (1) and the bush
(2) onto the gearbox mainshaft after first
oiling the two components and the shaft
itself. Check the bush for signs of seizure
or excessive wear. If these are found, replace the bush. Also measure the clearance between the steel bush (2) and the
bush in the clutch basket (3).
Standard clearance 0.010-0.112mm
Before you fit the clutch basket, check the wear on
the teeth of the primary transmission gear (A) and
on the gear (B) which carries the drive to the oil
pumps. Check too the condition of the teeth (C) on
the clutch basket which engage with the drive plates
(8). Manually check that there is not excessive tangential play in the relative rotational movement between the clutch basket and the primary gear which
is fitted to it via the silent-block. Unscrew the TDC
locking bolt to facilitate assembly of the clutch.
Fit the 18.3x35x1.5 washer (4) after first oiling its
housing in the clutch basket assembly (3).
50
betamotor.com
ASSEMBLY
Check the wear on the teeth (A) of the clutch centre
which engage with the driven plates.
Fit the clutch hub (5) and secure it with the nut (7)
after you have fitted the tabwasher (6).
Lock the clutch hub with the special tool and tighten the nut to 90 Nm.
Lock the nut (7) by pulling up the tabs on the
tabwasher (A).
Check the thickness of the clutch drive plates (8)
which must be not less than 2.8mm (thickness
when new: 3mm). Also check both the drive plates
(8) and the driven plates (9) for flatness: the discs
must not undulate excessively, as this could lead to
low friction when the two are in engagement.
Fit a drive plate first into the clutch basket, and then
the others, taking care that no two plates of the
same type are in contact with each other.
N.B. Remember to oil the plates during the assembly process. Recommended procedure is to keep the
drive plates in an oil-bath for 10-12 hours before assembly.
A
51
betamotor.com
ASSEMBLY
After you have fitted all the friction plates, fit the
pressure plate lifter (10) in the central hole in the
clutch basket, together with the lifter needle roller
bearing (11) and the corresponding washer (12).
Check the wear on the needle roller bearing and
the contact surfaces. Replace the components if
they show excess wear.
Check the length of the springs (14):
Minimum value 33.3mm (33.8mm when new).
Fit the clutch pressure plate (13), the clutch springs
(14), the special washers (15) and the M6x16 bolts
(16). Tighten the bolts (16) in diagonal sequence to
10 Nm. Tighten the TDC locking bolt once more.
52
betamotor.com
ASSEMBLY
4.13 FLYWHEEL
Carefully degrease the taper on the crankshaft before proceeding to fit the flywheel.
Insert the drive key (1) in the keyway machined for
it in the left-hand crankshaft journal, using a rubber
hammer if necessary.
Fit the flywheel (2) and secure it with the flanged
nut (3), tightening to a torque of 120 Nm.
53
betamotor.com
ASSEMBLY
4.14 PISTON AND CYLINDER
4.14.1 measurements and checks
4.14.1.1 Cylinder
Check whether the lower and upper surfaces of the
cylinder show deformation. Use a surface plate and
a dial gauge to measure for flatness.
The limit value for deformation is 0.05mm.
Recondition the cylinder in the event of out-of-limits values.
Check whether the inner surface of the cylinder
shows signs of seizure or excessive wear. If it does,
recondition the surface.
Measure the internal diameter of the cylinder on
two axes at right angles to each other, X (parallel to
the crankshaft) and Y (perpendicular to the crankshaft) and at three different levels. Use the largest
value measured for subsequently determining the
maximum piston-cylinder clearance.
N.B. The front side of the cylinder (exhaust side) is
marked with the letter for the selection grade. This is
needed for correct matching with the piston, as both
must be of the same grade (the piston is marked on
the crown with its diameter measurement).
selection grade
A
76,960±0,005mm
B
76,970±0,005mm
C
76,980±0,005mm
4.14.1.2 Piston
Check the sliding surfaces for wear and scoring,
and look for dark areas below the oil scraper ring
groove. Replace the piston if these are found.
Use a micrometer to measure the diameter of the
piston in a direction perpendicular to the piston pin,
at a distance of 7mm from the base of the skirt.
Once the measurement of the diameters of the cylinder and piston has been carried out, the clearance
between the two can be determined:
Limit of play 0.1mm
7mm
Measure the thickness of the two compression
rings.
Minimum thickness of upper ring: 0.87 mm
Minimum thickness of lower ring: 0,77 mm
Change the compression rings if their thicknesses
are lower than these limits.
54
betamotor.com
ASSEMBLY
Fit the piston ring into the cylinder and use a feeler
gauge to measure the gap between the two ends of
the ring. When inserting the ring into the bore, use
the top of the piston to ensure that the ring is sitting
parallel to its working plane, and position it approximately 10mm from the top surface of the cylinder.
Maximum gap, compression rings: 0.8mm
Maximum gap, oil scraper ring: 1.0mm
Replace the rings if the values for the gaps exceed
those listed.
If the gap exceeds the limit value even when using a
new piston ring, the cylinder must be replaced.
Clean the grooves for the compression rings and for
the oil scraper ring of carbon residues from combustion.
Use a feeler gauge to measure the play between
the compression rings and the ring grooves in the
piston. If these values exceed the maximum, with
piston ring thicknesses within the prescribed limits,
the piston must be replaced.
Maximum play: 0.12mm
Measure the diameter of the piston pin and, if this
value is below the limit, replace the piston pin.
Piston pin minimum diameter: 15.995mm
Replace the piston pin also if you detect excessive
scoring or discolouration of the surface in contact
with the connecting rod small end bush.
Measure the diameter of the hole in the piston for
housing the piston pin. If the play between the piston pin and its housing exceeds the limit, with the
piston pin diameter within the prescribed limits,
change the piston.
Limit of play 0.04mm
55
betamotor.com
ASSEMBLY
Measure the internal diameter of the conrod small
end and then determine the play with the piston
pin. If this value exceeds the limit, with the diameter
of the piston pin within limits, replace the connecting rod.
Limit of play 0.07mm
3
1
2
4.14.2 fitting
4.14.2.1 Studs
Insert the two dowel pins (1) into the right-hand
crankcase, using a hammer to ensure that they go
fully home in their housings.
Insert the studs into their housings by the longer
threaded section, after you have first applied a
thread lock. Use a nut and locknut (2) for screwing
in the studs. Tighten to 30 Nm.
Fit the cylinder base gasket, taking care that it does
not obstruct the oilway (3).
4.14.2.2 Piston
Fit the oil scraper ring (3) in the lower ring groove
in the piston, inserting the spring (1) first, followed
by the two flat sections (2) with their gaps facing in
opposite directions.
Fit the two compression rings (4, 5) into their
grooves with the letter marking facing upwards and
with the ring gaps facing in opposite directions.
Check after fitting that the rings can rotate in their
grooves without excessive impediment.
N.B. When fitted, the piston must be have the arrow
(6) facing towards the front of the engine (exhaust
side).
56
betamotor.com
ASSEMBLY
4.14.2.3 Cylinder
Fit the oil jet (1) and the M6x12 bolt (2) for draining the cooling water with the appropriate washer.
Tighten the bolt to 8 Nm.
1
2
Insert the piston into the cylinder from below, positioning it in the correct direction (with the arrow
pointing in the bike’s direction of travel). Lubricate
the contact surfaces well, and take care not to damage the piston rings. Next, insert the circlip for retaining the piston pin, on one side only. Make sure
that the open part of the circlip is facing either upwards or downwards.
Slide the cylinder down between the studs until the
small end of the conrod is aligned with the piston
pin housing. Then insert the piston pin from the side
which is still open, and lock it with its circlip, having
previously lubricated the surfaces of the piston pin
itself and of its housing.
N.B. Ensure that the cylinder base gasket is in position before fitting the cylinder.
N.B. Ensure that both circlips are fitted with the opening facing either upwards or downwards.
Bring the cylinder down until it makes contact with
the crankcase, if necessary with the help of a rubber hammer to settle it in position. Ensure that the
57
betamotor.com
ASSEMBLY
camchain passes freely through the timing case on
the right-hand side of the engine.
2
1
3
Insert the two dowels (1) and the movable camchain guide (2). Fit the cylinder head gasket, taking
care that it does not obstruct the oilway (3).
1
4.15 CYLINDER HEAD COVER
Before proceeding to fit the head cover, carry out
the following checks:
- Check the condition of the surfaces of the rocker
spindles (8). Replace them if you detect excessive
wear or scoring. Measure their external diameter
and, if this is below the limit, replace the rocker
spindle.
Limit value 11.93mm
- Check that the rollers (4) in the rocker arms run
freely. If you detect excessive radial clearance, replace the rocker arms.
- Check the adjuster nuts (6) to ensure that the surfaces that bear on the rocker arms are flat.
- Measure the diameter of the spindle hole in the
rocker arm. If the play of the spindle in the hole is
outside the limit value, replace the rocker arm.
Limit of play 0.10mm
Insert the oil plug (1) in its housing using a pin
punch.
Fit the adjuster screws (5) and the adjuster nuts on
both rockers.
58
betamotor.com
ASSEMBLY
Fit the inlet rocker (2) and the exhaust rocker (3)
as indicated in the photo, inserting the 12x17x0.5
thrust washers (7) between the rockers and the
head cover, after you have lubricated them well
with engine oil.
Insert the rocker spindles (8) with the cutouts (A)
adjacent to the straight-through holes (B) for the
cylinder-head hold-down bolts, and with the end
containing a threaded hole facing outwards. This
hole is used for locating the rocker spindles in the
correct position using an M4 bolt.
B
A
7
7
B
3
B
7
7
2
B
4.16 CYLINDER HEAD
4.16.1 checks
Check the valve guides with a ø5H7 go/no-go gauge.
If the gauge is easily introduced into the guide, then
the guide must be replaced.
Check whether the valve stems show signs of wear,
scoring or damage. Then measure their diameter
and, if this value is below the limit, replace the
valve.
Minimum diameter 4.978mm
Check the valve stem/valve guide play. To do this,
locate the valve in its guide with the top surface of
the valve stem flush with the guide, and measure
the maximum radial oscillation of the valve head.
Play when new 0.08mm
Limit of play 0.25mm
If the play exceeds this limit and the diameter of the
valve stem is within the prescribed limits, replace
the guide. Otherwise, replace both parts, unless the
diameter of the guide is in tolerance, in which case
only the valve is to be replaced.
Check the wear and the sealing surface of the valve
seats. To do this, apply a thin layer of engineer’s
Prussian blue to the contact area of the valve with
59
betamotor.com
ASSEMBLY
the seat. Then insert the valve into the guide until it
is pressing against the seat, and rotate it on its axis.
When the valve is removed, the dye will be missing
on the contact area. The width of this contact area
must fall within certain limits:
Standard 1.15-1.40mm
Service limit 1.80mm
If the sealing area is outside the service limit, the
seat must be recut.
Recut the seat also if excessive roughness is visible,
or if there is damage due to impact.
Check the free length L0 of the inner and outer
valve springs. Change the springs if their free length
is below the minimum value:
Minimum L0 outer spring 38.6mm
(39mm when new)
Minimum L0 inner spring 31.5mm
(31.8mm when new)
Measure the compression strength of the valve
springs with a pressure dynamometer at length L1:
Outer spring: F=200±9N at L1=30mm
Inner spring: F=110±6N at L1=26.5mm
Using a suitable tester, check how well the valves
seal once the head is assembled.
60
betamotor.com
ASSEMBLY
4.16.2 fitting
Insert the oil plug (1) using a pin punch.
Fit the lower spring caps (2) and then the valve
guide oilseals (3). Take care not to confuse the lower spring caps with the upper ones. The upper caps
differ from the lower ones in that they have a more
marked bevel on the opposite side to the spring.
N.B. Change the valve guide oilseals each time an
inspection of the head is carried out and the valves
are removed.
Fit the outer springs (4) and the inner springs (5),
and then the spring caps.
N.B springs have a coloured paintmark. Fit them with
this mark facing upwards.
After you have greased the valves and fitted them
into their guides (inlet 7, exhaust 8), secure them
with the split collets (9) using the special tool (A).
The operation must be carried out individually for
each valve.
N.B. Used valves must always be refitted in the same
guide as they were in before dismantling.
A
9
61
betamotor.com
ASSEMBLY
Apply a few taps to the upper spring caps with a
double rubber hammer to help the split collets to
settle.
Fit the two roller bearings (10, 11) for the water
pump shaft into their housings in the head. The
smaller-diameter bearing (10) should be driven
fully home in its housing. The other bearing (11)
does not have a stop, therefore you must ensure
that it is located flush with the inner surface of the
timing case.
Fit the first oilseal (12) with the open side facing towards the head to ensure an oiltight seal, and the
second (13) with the open side facing outwards so
as to avoid water leaks from the pump into the timing case. Remember to apply grease to the outer
surfaces of the oilseal.
4.17 VALVEGEAR
4.17.1 Pre-assembly of camshaft
Check the wear on the contact surfaces of the cams
with the rockers and, if you detect excessive wear or
damage, replace the camshaft (1).
A
Measure the maximum length of the cams (A) and
the diameter of the base circle (B).
Standard length of cam 33.258±0.030mm
Diameter of cam base circle 28±0.015mm
Fit the camshaft sprocket (2) onto the camshaft (1)
with the flat face towards the cams, securing it with
the M6x10 screws and tightening to 10 Nm after
applying medium-strength thread lock.
B
62
betamotor.com
ASSEMBLY
Fit the decompressor weight (4) and the relative
spring (5). The spring must be preloaded by half a
turn when fitted. Then check that the decompressor
mass returns automatically to its initial position after being displaced. If this does not happen, replace
the spring.
N.B. Oil the contact areas between the decompressor
mass and the other parts in the camshaft assembly.
5
4
4.17.2 Fitting the valvegear
Fit the head (1) onto the cylinder, tapping it several
times in the area of the dowels in order to facilitate
seating.
Fit the washers (2) and screw the nuts (3) onto the
studs, tightening them in diagonal sequence, starting with the studs in proximity to the dowels. Tighten to a torque of 30 Nm.
Tighten the M6x25 bolt (4) to 10 Nm.
Fit the water pump drive sprocket (5) into its housing in the timing case, with the smaller-diameter
face towards the inside, and then the water pump
shaft (6) after you have lubricated it with oil.
Check the diameter of the water pump shaft in the
area where it makes contact with the seals. Signs of
wear may be visible in this area. If the diameter is
less than the limit value, replace the shaft to avoid
sealing problems.
Minimum diameter 9.7mm
63
betamotor.com
ASSEMBLY
9
Pass the camchain around the camshaft sprocket,
and fit onto the camshaft first the sealed bearing (8)
and then the bearing on the chain side (9).
8
A
Take care to time up the camshaft properly. The
crankshaft is locked at TDC by the special bolt which
was fitted earlier (see 4.11). Position the camshaft
so that the timing mark (A) is horizontal on the exhaust valve side. In this way, the entire assembly is
positioned at TDC between the compression stroke
and the combustion stroke, i.e. when the valves are
at rest and there is clearance in the rockers which
will later need to be adjusted, as is explained further on in this manual. This facilitates the fitting of
the head cover and, consequently, the rockers.
N.B. The correct way to check the timing is to tension the camchain by pressing on the movable chain
guide with a screwdriver.
Screw the water pump shaft (6) into the gear (5)
(which is locked by the camchain) using the appropriate special tool.
Locate the dowels (12) in the head and fit the camshaft end plug (11) with its O-ring (10) into place
in its groove.
Put some silicone sealant on the contact surface
with the head cover and refit the cover (13) to the
cylinder head, ensuring that the rocker spindles are
positioned correctly, i.e. so as to allow the subsequent fitting of the cover bolts.
Fit the head cover bolts: two M6x25 (14), four
M6x55 (16) with the corresponding washers (15),
and four M6x35 (17), tightening them to 10 Nm.
64
betamotor.com
ASSEMBLY
Seal the holes in the head cover for the rocker spindles with the appropriate gaskets (18) and plugs
(19).
Adjust the valve clearances, inserting a feeler gauge
between the adjuster and the top of the valve, and
using the adjuster screw to regulate the play.
Inlet clearance 0.10mm.
Exhaust clearance 0.15mm.
When the clearance is correct, tighten the locknuts
to 11 Nm and seat the O-rings for sealing the valve
covers in the grooves machined in the head cover.
Use silicone sealant to help the O-ring adhere in
its groove, and to prevent it from moving when the
valve cover is removed.
Fit the valve covers using M6x16 bolts and tighten
them to 8 Nm.
Fit the water pump impeller (20), securing it with
the circlip (21). Apply some grease in the area of
the threads in order to help the gasket (22) to adhere, and fit the cover (23) to the pump, tightening
the three M6x20 bolts to 10 Nm.
65
betamotor.com
ASSEMBLY
Check that the tensioner plunger (A) moves freely,
and check the teeth (B) on the plunger for wear.
Before fitting, push the plunger all the way into the
tensioner body.
B
A
Fit the tensioner body and its gasket, retaining it
with M6x16 bolts tightened to 8 Nm. Use a screwdriver to push the plunger so as to put the camchain
under tension. Then insert the spring and washer
and, finally, screw in the bolt.
4.18 CLUTCH CASING
Before you proceed to fit the clutch casing, oil all
the moving parts well, and also the areas which that
have oil passing through them, such as the crankshaft and the oil jet. Then locate the dowels (A).
A
A
66
betamotor.com
ASSEMBLY
Grease the areas adjacent to the threaded holes so
as to help the clutch casing gasket (1) to adhere,
and thus to prevent it from becoming detached the
next time the cover is opened.
Fit the clutch casing (2) with its retaining bolts,
tightening them to 10 Nm.
Insert the O-rings for the clutch cover (3) and the
oil filter cover (4) into the grooves formed in the
clutch casing, applying some grease to make sure
they adhere to their housings.
Fit the output oil filter (5) and the spring (6) after
you have oiled the filter seat.
Fit the clutch cover (8) and the oil filter cover (7),
retaining them with M6x20 bolts (four for the clutch
cover and three for the oil filter cover). Tighten the
bolts to 10 Nm. Refit the oil filler plug (10), tightening it to 10 Nm, after first applying the 16x22.5x1
gasket (9).
67
betamotor.com
ASSEMBLY
4.19 IGNITION
Insert the two dowels (1) into the left-hand crankcase and apply some grease in the area of the
threaded holes in order to help the flywheel cover
gasket (8) to adhere.
N.B. Before you apply the gasket, cut off the excess
section as shown in the picture above.
Fit the stator (3) to the flywheel cover (2), retaining
it with three M5x25 screws (4). Tighten the screws
to 6 Nm. Take care that the stator cable guide plate
is facing towards the inside of the cover.
Fit the cable retaining plate (5) and the pickup (6),
tightening the two M6x12 retaining bolts to 8 Nm.
68
betamotor.com
ASSEMBLY
Fit the flywheel cover to the left-hand crankcase half
and retain it with the bolts indicated in the picture
above. Tighten the bolts to 10 Nm.
N.B. Do not tighten the two M6x35 screws at this
stage, as they will also be used to retain the sprocket
cover which will be fitted only after the chain has
been passed around the sprocket, once the motorcycle is assembled.
4.20 FINAL DETAILS
Insert first the ball (1) and then the clutch pushrod
(2) after you have lubricated them with engine oil.
Fit the front sprocket (4) to the output end of the
layshaft, retaining it with the two circlips (3, 5).
Fit the air bleed screw for the cooling circuit (9) with
its washer (8) and the water drain screw (7) with its
washer (6), tightening both of them to 8 Nm.
Connect the carburettor flange (10) and tighten the
two M6x16 bolts (11) to 10 Nm.
69
betamotor.com
ASSEMBLY
Fit the exhaust flange (12) with four M6x15 screws
(14) tightened to 10 Nm. Under the heads of the
screws fit the two plates (13) for anchoring the exhaust collector support springs. These plates are fitted to the top right and bottom left bolts, looking at
the engine from the front (exhaust side).
Fit the special washer between the TDC bolt and its
housing on the crankcase. As a result, the crankshaft
is no longer locked.
Fit the kickstart lever and check that the whole kickstart system moves correctly.
70
betamotor.com
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertising