Page 22 of 754
CHAPTER 4
ENGINE
SEAT, FUEL TANK
AND SIDE COVERS
..................................4-1
EXHAUST PIPE AND SILENCER
.............4-3
RADIATOR
................................................4-5
CARBURETOR
..........................................4-8
CAMSHAFTS
...........................................4-21
CYLINDER HEAD
....................................4-29
VALVES AND VALVE SPRINGS
............4-33
CYLINDER AND PISTON
........................4-42
CLUTCH
...................................................4-48
OIL FILTER, WATER PUMP
AND CRANKCASE COVER (RIGHT)
.....4-55
BALANCER
.............................................4-62
OIL PUMP
................................................4-65
KICK AXLE AND SHIFT SHAFT
.............4-69
AC MAGNETO
AND STARTER CLUTCH
........................4-76
ENGINE REMOVAL
.................................4-83
CRANKCASE AND CRANKSHAFT
........4-89
TRANSMISSION, SHIFT CAM
AND SHIFT FORK
...................................4-98
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL
.......5-1
FRONT BRAKE AND REAR BRAKE
.....5-11
FRONT FORK
..........................................5-27
HANDLEBAR
...........................................5-40
STEERING
...............................................5-46
SWINGARM
.............................................5-52
REAR SHOCK ABSORBER
....................5-60
Page 66 of 754
1 - 18
GEN
INFO
BREAK-IN PROCEDURES
1. Before starting the engine, fill the fuel
tank with the fuel.
2. Perform the pre-operation checks on the
machine.
3. Start and warm up the engine. Check the
idle speed, and check the operation of
the controls and the “ENGINE STOP”
button. Then, restart the engine and
check its operation within no more than 5
minutes after it is restarted.
4. Operate the machine in the lower gears
at moderate throttle openings for five to
eight minutes.
5. Check how the engine runs when the
machine is ridden with the throttle 1/4 to
1/2 open (low to medium speed) for
about one hour.
6. Restart the engine and check the opera-
tion of the machine throughout its entire
operating range. Restart the machine
and operate it for about 10 to 15 more
minutes. The machine will now be ready
to race.
CAUTION:
After the break-in or before each race,
you must check the entire machine for
loose fittings and fasteners as per
“TORQUE-CHECK POINTS”.
Tighten all such fasteners as required.
When any of the following parts have
been replaced, they must be broken in.
CYLINDER AND CRANKSHAFT:
About one hour of break-in operation is
necessary.
PISTON, RING, VALVES, CAMSHAFTS
AND GEARS:
These parts require about 30 minutes of
break-in operation at half-throttle or less.
Observe the condition of the engine care-
fully during operation.
STARTING AND BREAK-IN
Page 79 of 754
SPEC
2 - 4
MAINTENANCE SPECIFICATIONS
MAINTENANCE SPECIFICATIONS
ENGINE
Item Standard Limit
Cylinder head:
Warp limit ---- 0.05 mm
(0.002 in)
Cylinder:
Bore size 95.00 ~ 95.01 mm
(3.7402 ~ 3.7406 in)----
Out of round limit ---- 0.05 mm
(0.002 in)
Camshaft:
Drive method Chain drive (Left) ----
Camshaft cap inside diameter 22.000 ~ 22.021 mm
(0.8661 ~ 0.8670 in)----
Camshaft journal diameter 21.967 ~ 21.980 mm
(0.8648 ~ 0.8654 in)----
Shaft-to-cap clearance 0.020 ~ 0.054 mm
(0.0008 ~ 0.0021 in)0.08 mm
(0.003 in)
Cam dimensions
Intake“A”31.200 ~ 31.300 mm
(1.2283 ~ 1.2323 in)31.100 mm
(1.2244 in)
“B”22.550 ~ 22.650 mm
(0.8878 ~ 0.8917 in)22.450 mm
(0.8839 in)
Exhaust“A”30.950 ~ 31.050 mm
(1.2185 ~ 1.2224 in)30.850 mm
(1.2146 in)
“B”22.494 ~ 22.594 mm
(0.8856 ~ 0.8895 in)22.394 mm
(0.8817 in)
Camshaft runout limit ---- 0.03 mm
(0.0012 in)
A
B
Page 85 of 754
SPEC
2 - 10
MAINTENANCE SPECIFICATIONS
Item Standard
Lubrication chart:
Pressure feed
Splashed scavenge
Oil strainer
Oil pan Oil pump rotor 2
Oil pump rotor 1
Oil tank
Oil filter
Check ball
Cylinder head
Crank pinPiston pinPiston
Drive axleMain axleTransmission gears
Camshaft
Valve lifter
Page 86 of 754
SPEC
2 - 11
MAINTENANCE SPECIFICATIONS
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Spark plug M10S
×
1.0 1 13 1.3 9.4
Camshaft cap M6
×
1.0 10 10 1.0 7.2
Cylinder head blind plug screw M12
×
1.0 1 28 2.8 20
Cylinder head (stud bolt) M6
×
1.0 2 7 0.7 5.1
M8
×
1.25 1 15 1.5 11
(bolt) M10
×
1.25 4 Refer to NOTE.*
1
(nut) M6
×
1.0 2 10 1.0 7.2
Cylinder head cover M6
×
1.0 2 10 1.0 7.2
Cylinder M6
×
1.0 1 10 1.0 7.2
Timing chain tensioner M6
×
1.0 2 10 1.0 7.2
Tensioner cap bolt M6
×
1.0 1 7 0.7 5.1
Timing chain guide (rear) M6
×
1.0 2 10 1.0 7.2
Exhaust pipe (nut) M8
×
1.25 1 13 1.3 9.4
(bolt) M8
×
1.25 1 24 2.4 17
Silencer M8
×
1.25 2 35 3.5 25
Silencer clamp M8
×
1.25 1 16 1.6 11
Exhaust pipe protector M6
×
1.0 3 10 1.0 7.2
Spark arrester (for USA) M6
×
1.0 3 10 1.0 7.2
Silencer end pipe (for USA) M6
×
1.0 1 10 1.0 7.2
Carburetor joint clamp (cylinder head side) M5
×
0.8 1 3 0.3 2.2
Carburetor joint clamp (carburetor side) M4
×
0.7 1 3 0.3 2.2
Air filter case M6
×
1.0 2 8 0.8 5.8
Air filter joint clamp M6
×
1.0 1 3 0.3 2.2
Air filter joint and air filter case M5
×
0.8 1 4 0.4 2.9
Throttle cable (pull) M6
×
1.0 1 4 0.4 2.9
Throttle cable (return) M12
×
1.0 1 11 1.1 8.0
Throttle cable cover M5
×
0.8 2 4 0.4 2.9
Hot starter plunger M12
×
1.0 1 2 0.2 1.4
Radiator panel (upper) M6
×
1.0 2 10 1.0 7.2
Radiator M6
×
1.0 6 10 1.0 7.2
Radiator hose clamp M6
×
1.0 8 2 0.2 1.4
Radiator pipe 1, 2 M10
×
1.0 2 10 1.0 7.2
Impeller M8
×
1.25 1 14 1.4 10
Water pump housing cover M6
×
1.0 3 10 1.0 7.2
Coolant drain bolt M6
×
1.0 1 10 1.0 7.2
Oil pump cover M4
×
0.7 1 2 0.2 1.4
Oil pump M6 × 1.0 3 10 1.0 7.2
Engine oil drain bolt (oil filter) M6 × 1.0 1 10 1.0 7.2
Oil filter cover M6 × 1.0 2 10 1.0 7.2
Oil delivery pipe 1 M10 × 1.25 1 20 2.0 14
M8 × 1.25 2 18 1.8 13
Oil delivery pipe 2 M6 × 1.0 1 10 1.0 7.2
Oil hose M6 × 1.0 2 8 0.8 5.8
Page 156 of 754
2 - 21
SPEC
LUBRICATION DIAGRAMS
LUBRICATION DIAGRAMS
1
Oil delivery pipe
2
Intake camshaft
3
Exhaust camshaft
4
Oil cleaner element
5
Oil pump
6
Main axle
7
Drive axle
7
6
543 2
14
5
A - A
D - D
G
G
D
D A
A
Page 158 of 754
2 - 22
SPEC
LUBRICATION DIAGRAMS
1
Camshaft
2
Connecting rod
3
Oil cleaner element
4
Crankshaft
5
Main axle
6
Drive axle
7
Oil delivery pipe
1
2
3
4
5
67
Page 172 of 754
3 - 1
INSP
ADJ
MAINTENANCE INTERVALS
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the
required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in
maintaining and lubricating your machine, consult your Yamaha dealer.
ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)
As re-
quiredRemarks
ENGINE OIL
Replace
●
●
VALVES
Check the valve clearances
Inspect
Replace
●
●
●
●
The engine must be cold.
Check the valve seats
and valve stems for wear.
VALVE SPRINGS
Inspect
Replace
●
●
Check the free length and
the tilt.
VALVE LIFTERS
Inspect
Replace
●
●
Check for scratches and
wear.
CAMSHAFTS
Inspect
Replace
●
●
Inspect the camshaft sur-
face.
Inspect the decompres-
sion system
CAMSHAFT SPROCKETS
Inspect
Replace
●
●
Check for wear on the
teeth and for damage.
PISTON
Inspect
Clean
Replace
●
●
●
●
Inspect crack
Inspect carbon deposits
and eliminate them.
PISTON RING
Inspect
Replace
●
●
●
Check ring end gap
PISTON PIN
Inspect
Replace
●
●
CYLINDER HEAD
Inspect and clean
●
Inspect carbon deposits
and eliminate them.
Change gasket
CYLINDER
Inspect and clean
Replace
●
●
Inspect score marks
Inspect wear
CLUTCH
Inspect and adjust
Replace
●
●
●
Inspect housing, friction
plate, clutch plate and
spring
TRANSMISSION
Inspect
Replace bearing
●
●
