the outside diameter [A] of each piston 5 mm
• Measure
(0.20 in.) [B] up from the bottom of the piston at a right
angle to the direction of the piston pin.
If the measurement is under service limit, replace the piston.
Piston Diameter
Standard:
75.959  75.974 mm (2.9905  2.9911 in.)
Service Limit: 75.81 mm (2.985 in.)

CRANKSHAFT/TRANSMISSION 9-31
Pistons
Piston Ring, Piston Ring Groove Wear Inspection

for uneven groove wear by inspecting the ring seat• Check
ing.

•

The rings should fit perfectly parallel to groove surfaces.
If not, replace the piston and all the piston rings.
With the piston rings in their grooves, make several measurements with a thickness gauge [A] to determine piston
ring/groove clearance.
Piston Ring/Groove Clearance
Standard:
Top

0.035  0.070 mm (0.00138  0.00276 in.)

Second

0.030  0.065 mm (0.00118  0.00256 in.)

Service Limit:
Top

0.17 mm (0.0067 in.)

Second

0.17 mm (0.0067 in.)

Piston Ring Groove Width Inspection

the piston ring groove width.
•○Measure
Use a vernier caliper at several points around the piston.
Piston Ring Groove Width
Standard:
Top [A]

0.82  0.84 mm (0.0323  0.0331 in.)

Second [B] 0.82  0.84 mm (0.0323  0.0331 in.)
Service Limit:
Top

0.92 mm (0.036 in.)

Second

0.92 mm (0.036 in.)

If the width of any of the two grooves is wider than the
service limit at any point, replace the piston.

Piston Ring Thickness Inspection

the piston ring thickness.
•○Measure
Use the micrometer to measure at several points around
the ring.
Piston Ring Thickness
Standard:
Top [A]

0.770  0.785 mm (0.0303  0.0309 in.)

Second [B] 0.775  0.790 mm (0.0305  0.0311 in.)
Service Limit:
Top

0.70 mm (0.0276 in.)

Second

0.71 mm (0.0280 in.)

If any of the measurements is less than the service limit
on either of the rings, replace all the rings.

NOTE

○When using new rings in a used piston, check for uneven groove wear. The rings should fit perfectly parallel
to the groove sides. If not, replace the piston.

9-32 CRANKSHAFT/TRANSMISSION
Pistons
Piston Ring End Gap Inspection

the piston ring [A] inside the cylinder (upper
• Place
crankcase), using the piston to locate the ring squarely

•

in place. Set it close to the bottom of the cylinder, where
cylinder wear is low.
Measure the gap [B] between the ends of the ring with a
thickness gauge.
Piston Ring End Gap
Standard:
Top

0.15  0.25 mm (0.0059  0.0098 in.)

Second

0.35  0.50 mm (0.0138  0.0197 in.)

Service Limit:
Top

0.6 mm (0.02 in.)

Second

0.8 mm (0.03 in.)

If the end gap of either ring is greater than the service
limit, replace all the rings.

CRANKSHAFT/TRANSMISSION 9-33
Balancer
Balancer Removal

• Remove:
Oil Pan (see Oil Pan Removal in the Engine Lubrication

•

System chapter)
Balancer Shaft Clamp Lever Bolt [A]
Balancer Shaft Clamp Bolt [B]
Balancer Shaft Clamp Lever [C]
Balancer Shaft [D]
Balancer Shaft Oil Seal
Take the balancer assembly off the crankcase.

Balancer Installation

the crankshaft at #2, 3 positions TDC or at #1, 4
• Position
positions TDC.
the balancer assembly as follows.
• Install
Engage
balancer gear and the crankshaft gear.
•○Align thethe
punch mark [A] on the weight and the projection

•
•
•
•
•

[B] on the crankcase.
Insert the balancer shaft until it is bottomed.
Replace the balancer shaft oil seal with a new one.
Apply grease to the oil seal lips.
Install the oil seal so that its surface is flush with the end
of hole.
Install:
Balancer Shaft Clamp Lever [C]
Balancer Shaft Clamp Bolt [D] (Temporarily)

a non-permanent locking agent to the balancer
• Apply
shaft clamp lever bolt [A].
• Tighten:
Torque - Balancer Shaft Clamp Lever Bolt: 25 N·m (2.5
kgf·m, 18 ft·lb)

the mark [B] on the balancer shaft to the engine
• Face
forward [C].
• Tighten:
Torque - Balancer Shaft Clamp Bolt: 10 N·m (1.0 kgf·m, 89
in·lb)

Balancer Adjustment

the left lower fairing (see Lower Fairing Removal
• Remove
in the Frame chapter).
the engine and warm it up thoroughly.
• Start
Adjust
the balancer gear backlash with the engine idling.
• The amount
of backlash can be changed by turning the

•
•
•

balancer shaft which has eccentric journals.
Start the engine and let it idle.
Loosen the clamp bolt [A] and turn the balancer shaft [B]
clockwise [C] until the balancer gear makes a whining
sound.
Turn the shaft counterclockwise [D] until the balancer gear
whining sound disappears and tighten the clamp bolt.
Torque - Balancer Shaft Clamp Bolt: 10 N·m (1.0 kgf·m, 89
in·lb)

9-34 CRANKSHAFT/TRANSMISSION
Balancer
Balancer Damper Inspection

the balancer and disassemble the weight and
• Remove
gear assembly.
inspect the rubber dampers [A].
• Visually
If they appear damaged or deteriorated, replace them.

Balancer Assembly

molybdenum disulfide oil solution to the ribs of the
• Apply
balancer [A].

molybdenum disulfide oil solution to the ribs [A] of
• Apply
the balancer gear.
that the rubber dampers [B] are in place.
•○Check
Face the linked portion [C] to the bottom.

the balancer weight [A] and the gear [B].
•○Assemble
Align the punch mark [C] of the balancer weight and the
groove [D] of the gear.

molybdenum disulfide oil solution to the needle
• Apply
bearings [A].
the needle bearings and the washers [B].
•○Install
Face the grooved side of the washer to inside.

CRANKSHAFT/TRANSMISSION 9-35
Torque Limiter
Torque Limiter Removal

• Remove:
Starter Motor (see Starter Motor Removal in the Electrical System chapter)
ABS Hydraulic Unit (ABS Equipped Models) (see ABS
Hydraulic Unit Removal in the Brakes chapter)
Throttle Body Assy Holder Clamps [A]
Breather Hose [B]
Disconnect the water temperature sensor connector [C].
Roll up the heat insulation rubber plate [D].

•
•
• Remove:
Torque Limiter Cover Bolts [A]
Torque Limiter Cover [B]

• Remove:
Torque Limiter Shaft Plug [A] and Gasket

the torque limiter shaft [A] using a suitable M5
• Remove
bolt [B].
• Remove:
Collar [C]
Torque Limiter [D]

Torque Limiter Installation

molybdenum disulfide grease to the torque limiter
• Apply
shaft [A].
the torque limiter [B], the collar [C] and the shaft.
•○Install
Face the large-hole end of the shaft to inside as shown.
the gasket [D] with a new one.
• Replace
Apply
a
non-permanent
locking agent to the torque limiter
• shaft plug [E].
• Tighten:
Torque - Torque Limiter Shaft Plug: 25 N·m (2.5 kgf·m, 18
ft·lb)

9-36 CRANKSHAFT/TRANSMISSION
Torque Limiter
the torque limiter cover with a new one.
• Replace
Using
a
high
flash-point solvent, clean off any oil or dirt on
• the mating surface
of the crankcase and the torque limiter

•

cover. Dry it with a clean cloth.
Apply liquid gasket [A] to the crankcase as shown.
Sealant - Liquid Gasket, TB1207B: 92104-2068

the torque limiter cover [A].
•○Install
Face the bulged side of the cover upward.

NOTE

○Make the application finish within 7 minutes when the
liquid gasket to the mating surface of the crankcase is
applied.
○Moreover fit the cover and tighten the bolts [B] just after
application of the liquid gasket.

• Tighten:
Torque - Torque Limiter Cover Bolts: 10 N·m (1.0 kgf·m, 89
in·lb)

• Install the removed parts (see appropriate chapters).

CRANKSHAFT/TRANSMISSION 9-37
Starter Motor Clutch
Starter Motor Clutch Removal

• Remove:
ABS Hydraulic Unit (ABS Equipped Models) (see ABS
Hydraulic Unit Removal in the Brakes chapter)
Torque Limiter (see Torque Limiter Removal)
Transmission Assy (see Transmission Assy Removal)
Starter Motor Clutch Shaft Holder Bolt [A]
Starter Motor Clutch Shaft Bolt [B]
Starter Motor Clutch Shaft Holder [C]
the starter motor clutch shaft [A] using a suitable
• Remove
M8 bolt [B].

the starter motor clutch [A] from the engine right
• Remove
side.

○Take care not to drop the starter motor clutch parts.

Starter Motor Clutch Installation

the O-ring [A] with a new one and apply grease
• Replace
to it.
molybdenum disulfide grease to the starter motor
• Apply
clutch shaft [B].
• Install:
Starter Motor Clutch [C]
Spacer (Small Diameter) [D]
Spacer (Large Diameter) [E]
Starter Motor Clutch Shaft
Starter Motor Clutch Shaft Holder [F]
○Face the O-ring side of the shaft to outside.
Apply a non-permanent locking agent to the starter motor clutch shaft bolt [G] and the starter motor clutch shaft
holder bolt [H].
Tighten:

•
•

Torque - Starter Motor Clutch Shaft Holder Bolt: 10 N·m
(1.0 kgf·m, 89 in·lb)
Starter Motor Clutch Shaft Bolt: 20 N·m (2.0 kgf·m,
15 ft·lb)

• Install the removed parts (see appropriate chapters).

9-38 CRANKSHAFT/TRANSMISSION
Starter Motor Clutch
Starter Motor Clutch Disassembly

the starter motor clutch (see Starter Motor Clutch
• Remove
Removal).
the drive gear [A] off the driven gear [B].
• Take
Remove
needle bearing [C].
• Remove the
the
snap ring [D].
• Take the one-way
clutch [E] off the driven gear.
•

Starter Motor Clutch Assembly

the one-way clutch [A] to the driven gear.
•○Install
Face the circlip side of the one-way clutch to inside.
the new snap ring [B] to the driven gear.
• Install
Install
the
drive gear [C] while turn it counterclockwise [D].
• Apply molybdenum
oil solution to the needle
• bearing [E], and installdisulfide
it.

Starter Motor Clutch Inspection

• Remove:
Starter Motor (see Starter Motor Removal in the Electri•

cal System chapter)
Torque Limiter Cover (see Torque limiter Removal)
Turn the torque limiter [A] by hand. The torque limiter
should turn backward freely [B], but should not turn forward.
If the starter motor clutch does not operate as it should or
if it makes noise, go to the next step.

the starter motor clutch, and visually inspect
• Disassemble
the clutch parts.
One-way Clutch [A]
Driven Gear [B]
If there is any worn or damaged part, replace it.
○Examine the drive gear [C] as well. Replace the clutch
gear if it is worn or damaged.

CRANKSHAFT/TRANSMISSION 9-39
Transmission
Transmission Assy Removal

• Remove:
Engine Sprocket (see Engine Sprocket Removal in the
Final Drive chapter)
Gear Position Sensor (see Gear Position Sensor Removal in the Electrical System chapter)
Collar [A]
O-ring [B]

• Remove:
Clutch (see Clutch Removal in the Clutch chapter)
•

Shift Shaft Assembly (see External Shift Mechanism Removal)
Remove the transmission case bolts [A], and take the
transmission assy [B] off the crankcase.

Transmission Assy Installation

the transmission assy (see Transmission Assy
• Assemble
Assembly).
sure that the dowel pins are in position.
• Be
Install
• Tighten:the transmission assy on the crankcase.
•
Torque - Transmission Case Bolts: 20 N·m (2.0 kgf·m, 15
ft·lb)

• Install:
Shift Shaft Assembly (see External Shift Mechanism Installation)
Shift Lever (see Shift Lever Installation)
Set the gear positioning lever to the neutral position.
Check that the drive and output shaft turn freely.

•
•
the O-ring [A] with a new one.
• Replace
grease to the O-ring and install it to its position on
• Apply
the output shaft [B].
the collar [C].
• Install
When
installing
oil seal [D], install it as follows.
• Apply grease to the
the oil seal lips.
• Apply oil to the outer
circumference of the oil seal so that
• it will go into place smoothly.
the oil seal to the crankcase so that the surface of
• Install
the oil seal is flush with the surface of the crankcase.
• Install the removed parts (see appropriate chapters).

9-40 CRANKSHAFT/TRANSMISSION
Transmission
Transmission Assy Disassembly

the transmission assy (see Transmission Assy
• Remove
Removal).
the following from the transmission case [A].
• Remove
Shift Rod [B]
Shift Forks [C]
Drive Shaft [D]
Output Shaft [E]

• Remove:
Shift Drum Cam Holder Bolt [A]
Shift Drum Cam [B]
Shift Drum [C]

Transmission Assy Assembly

the ball bearing [A] until it is bottomed.
•○Install
Face the oil seal side to the bottom.
Special Tool - Bearing Driver Set: 57001-1129

the bearing holder [B].
•○Install
Face the flat side to the bottom.
a non-permanent locking agent
• Apply
holder bolts [C].
• Tighten:

to the bearing

Torque - Transmission Case Bearing Holder Bolts (L = 15):
10 N·m (1.0 kgf·m, 89 in·lb)

• Install the dowel pins [D] until they are bottomed.

CRANKSHAFT/TRANSMISSION 9-41
Transmission
the ball bearing [A] until it is bottomed.
•○Install
Face the stepped side to the outside.
Special Tool - Bearing Driver Set: 57001-1129

the bearing holder [B].
•○Install
Face the flat side to the bottom.
a non-permanent locking
• Apply
holder bolts [C].
• Tighten:

agent to the bearing

Torque - Transmission Case Bearing Holder Bolts (L = 15):
10 N·m (1.0 kgf·m, 89 in·lb)

the ball bearing [D] until it is bottomed.
• Install
Install
the bearing holders [E].
•○Face the
flat side to the bottom.
Apply
a
non-permanent
locking agent to the bearing
• holder bolts [F].
• Tighten:
Torque - Transmission Case Bearing Holder Bolts (L = 14):
10 N·m (1.0 kgf·m, 89 in·lb)

the pin [G] until it is bottomed.
• Install
Apply
non-permanent locking agent to the shift shaft
• return aspring
pin [H].
• Tighten:
Torque - Shift Shaft Return Spring Pin: 29 N·m (3.0 kgf·m,
21 ft·lb)

• Install:
Shift Drum Assembly [A]
Pin [B]
Shift Drum Cam [C]
Align
the pin with the recess [D].
○
Apply a non-permanent locking agent to the threads of
the sift drum cam holder bolt, and tighten it.