None

1

○

None

Black

92139-0299 (1, 3, 5)
92139-0302 (2, 4)

None

None

Blue

92139-0298 (1, 3, 5)
92139-0301 (2, 4)

*: The bearing inserts for Nos. 2 and 4 journals have an oil groove, respectively.

CRANKSHAFT/TRANSMISSION 9-9
Special Tools and Sealants
Outside Circlip Pliers:
57001-144

Bearing Driver Set:
57001-1129

Piston Pin Puller Assembly:
57001-910

Liquid Gasket, TB1216B:
92104-1064

Piston Ring Compressor Grip:
57001-1095

Liquid Gasket, TB1207B:
92104-2068

Piston Ring Compressor Belt,
57001-1097

67 

79:

9-10 CRANKSHAFT/TRANSMISSION
Crankcase
Crankcase Splitting

the engine (see Engine Removal in the Engine
• Remove
Removal/Installation chapter).
the engine on a clean surface and hold the engine
• Set
steady while parts are being removed.
• Remove:
Cylinder Head (see Cylinder Head Removal in the Engine Top End chapter)
Starter Motor (see Starter Motor Removal in the Electrical System chapter)
Oil Pump (see Oil Pump Removal in the Engine Lubrication System chapter)
Alternator Rotor (see Alternator Rotor Removal in the
Electrical System chapter)
Transmission Assy (see Transmission Assy Removal)
Oil Cooler (see Oil Cooler Removal in the Engine Lubrication System chapter)
Oil Pan (see Oil Pan Removal in the Engine Lubrication
System chapter)
Oil Screen
the upper crankcase bolts, following the speci• Remove
fied sequence.
1. Loosen the M7 bolt [A].
2. Loosen the M8 bolts [B].

the lower crankcase bolts, following the specified
• Remove
sequence.
1. Loosen the M6 bolts [A].
2. Loosen the M7 bolts [B].
3. Loosen the M9 bolts [C].
Tap lightly around the crankcase mating surface with a
plastic mallet, and split the crankcase.
○Take care not to damage the crankcase.

•

CRANKSHAFT/TRANSMISSION 9-11
Crankcase
Crankcase Assembly
NOTICE
The upper and lower crankcase halves are machined at the factory in the assembled state, so the
crankcase halves must be replaced as a set.
a high flash-point solvent, clean off the mating sur• With
faces of the crankcase halves and wipe dry.

WARNING
Gasoline and low flash-point solvents can be
flammable and/or explosive and cause severe
burns. Clean the crankcase in a well-ventilated
area, and take care that there are no sparks or
flame anywhere near the working area; this includes any appliance with a pilot light. Do not use
gasoline or a low flash-point solvent to clean the
crankcase.
compressed air, blow out the oil passages in the
• Using
crankcase halves.
• Install the balancer (see Balancer Installation).
Upper Crankcase Assembly
When installing the breather plate, replace the gasket [A]
with a new one.

•

a non-permanent locking agent to the threads of
• Apply
the breather plate bolts [A] and tighten them.
Torque - Breather Plate Bolts: 10 N·m (1.0 kgf·m, 89 in·lb)

9-12 CRANKSHAFT/TRANSMISSION
Crankcase
the fitting [A] until it is bottomed.
• Install
View from Upside [B]
the plug [C] so that the plug surface [D] is flush with
• Install
the end of the hole.

○Face the large chamfer side [E] to inside.
View from Left Side [F]

Special Tool - Bearing Driver Set: 57001-1129

the plate [A] with a new one.
• Replace
Install
the
plate as shown.
• Apply a non-permanent
locking agent to the plate bolts
• [B].
• Tighten:
Torque - Plate Bolts: 5.0 N·m (0.51 kgf·m, 44 in·lb)

View from Right Side [C]

• Install:
Oil Jet Nozzle (Black) [A]
•

Oil Jet Nozzle (White) [B]
Tighten:
Torque - Oil Jet Nozzle (M5): 3.0 N·m (0.31 kgf·m, 27 in·lb)

Lower Crankcase Assembly
Install the ball bearing [A] and the oil level inspection window [B] until they are bottomed.
○Apply soap and water solution to the oil level inspection
window before installation.

•

Special Tool - Bearing Driver Set: 57001-1129

the new circlip [C].
• Install
Apply
a
• plug [D].non-permanent locking agent to the oil passage
• Tighten:
Torque - Oil Passage Plug (Tapered): 20 N·m (2.0 kgf·m, 15
ft·lb)
Oil Jet Nozzle (M10) [E]: 15 N·m (1.5 kgf·m, 11 ft·lb)

View from Right Side [F]

CRANKSHAFT/TRANSMISSION 9-13
Crankcase
the needle bearing [A] so that its surface is flush
• Install
with the end of hole [B].
the output shaft oil seal [C] and the shift shaft
• Replace
oil seal [D] with new ones, and install them so that their
surfaces are flush with the end of holes.
Apply grease to the oil seal lips.
Install the oil jet nozzle [E] so that its surface is flush with
the end of hole.
○Face the small diameter side to inside.
View from Left Side [F]

•
•

Special Tool - Bearing Driver Set: 57001-1129

• Tighten:
Torque - Oil Jet Nozzle (M8) [A]: 8.0 N·m (0.82 kgf·m, 71
in·lb)
Oil Jet Nozzle (M6) [B]: 5.0 N·m (0.51 kgf·m, 44
in·lb)

• Install:
Dowel Pins [C]
Dowel Pin (Pipe) [D]

Crankcase Halves Assembly
Install:
Crankshaft (see Crankshaft Installation)
Connecting Rods (see Connecting Rod Installation)

•

9-14 CRANKSHAFT/TRANSMISSION
Crankcase
a high flash-point solvent, clean off any oil or dirt
• Using
on the mating surface of the crankcase halves.
liquid gasket to the mating surface of the lower
• Apply
crankcase half as shown.
Sealant - Liquid Gasket, TB1216B [A]: 92104-1064
Liquid Gasket, TB1207B [B]: 92104-2068

NOTE

○Especially, apply liquid gasket so that it shall be filled up
on the groove [C].

○Do not apply liquid gasket to the inside of the grooves
[D].

NOTICE
Do not apply liquid gasket around the crankshaft
main bearing inserts and oil passage.

• Fit the lower crankcase half to the upper crankcase half.
NOTE

○Make the application finish within 20 minutes when the
liquid gasket (TB1216B) to the mating surface of the
lower crankcase half is applied.
○Make the application finish within 7 minutes when the
liquid gasket (TB1207B) to the mating surface of the
lower crankcase half is applied.
○Moreover fit the case and tighten the bolts just after
application of the liquid gasket.

CRANKSHAFT/TRANSMISSION 9-15
Crankcase

• Install the drive shaft bearing [A].
Special Tool - Bearing Driver Set: 57001-1129

○Face the oil seal side of the bearing to the bottom.

M9 bolt [A] has a copper plated washer [B], replace
• The
them with new ones.
molybdenum disulfide oil solution to both sides [C]
• Apply
of the washers and threads [D].

the lower crankcase bolts with the following pro• Tighten
cedures.
the M9 bolts and washers.
• Install
L = 113 mm (4.45 in.) [A]

•

L = 100 mm (3.94 in.) [B]
Tighten M9 bolts by following the sequence numbers [1 
10].
Torque - Crankcase Bolts (M9): 45 N·m (4.6 kgf·m, 33 ft·lb)

the M7 bolts.
• Install
L = 50 mm (2.0 in.) [A]

•

L = 45 mm (1.8 in.) [B]
Tighten:
Torque - Crankcase Bolts (M7): 20 N·m (2.0 kgf·m, 15 ft·lb)

9-16 CRANKSHAFT/TRANSMISSION
Crankcase
the M6 bolt washers with new ones.
• Replace
Install
the
bolts.
• L = 60 mmM6(2.4
in.) [A] (With Washer)
L = 45 mm (1.8 in.) [B]
L = 40 mm (1.6 in.) [C]
Install
the clamps [D] and washers [E] as shown.
○
Tighten:

•

Torque - Crankcase Bolts (M6): 12 N·m (1.2 kgf·m, 106 in·lb)

the upper crankcase bolts with the following pro• Tighten
cedures.
the M8 bolt washers with new ones.
• Replace
the M8 bolts [A] and washers.
• Install
Install
• Tighten:the M7 bolt [B].
•
Torque - Crankcase Bolts (M8): 27 N·m (2.8 kgf·m, 20 ft·lb)
Crankcase Bolt (M7): 20 N·m (2.0 kgf·m, 15 ft·lb)

tightening all crankcase bolts, check the following
• After
items.

○Wipe

up the liquid gasket that seeps out around the
crankcase mating surface.
○Crankshaft turns freely.
the drive shaft bearing until it is bottomed.
• Press
• Install:
Drive Shaft Bearing Holder [A]
Output Shaft Bearing Holder [B]
Face
the flat side [C] of the holders to inside.
○
Apply a non-permanent locking agent to the bearing
holder bolts [D].
Tighten:

•
•

Torque - Bearing Holder Bolts: 15 N·m (1.5 kgf·m, 11 ft·lb)

• Install the removed parts (see appropriate chapters).

CRANKSHAFT/TRANSMISSION 9-17
Crankshaft and Connecting Rods
Crankshaft Removal

the crankcase (see Crankcase Splitting).
• Split
• Remove:
Connecting Rod Big End Nuts [A]
Connecting Rod Big End Caps [B]

NOTE

○Mark and record the locations of the connecting rods
and their big end caps so that they can be reassembled
in their original positions.

• Remove the crankshaft [A].

the thrust washers [A] from the #3 main journal
• Remove
of the upper crankcase half as follows.

○Slide [B] the thrust washers upward and remove them.

Crankshaft Installation
NOTE

○If the crankshaft is replaced with a new one, refer to
the Connecting Rod Big End Bearing/Crankshaft Main
Bearing Insert Selection in the Specifications.

NOTICE
If the crankshaft, bearing inserts, or crankcase
halves are replaced with new ones, select the bearing inserts and check clearance with a plastigage
(press gauge) before assembling engine to be sure
the correct bearing inserts are installed.
molybdenum disulfide oil solution to the crankshaft
• Apply
main bearing inserts.
• Install:
Crankshaft
Connecting Rod Big End Caps (see Connecting Rod Installation)

9-18 CRANKSHAFT/TRANSMISSION
Crankshaft and Connecting Rods
molybdenum disulfide grease to the grooved side
• Apply
[A] of the thrust washers.
the thrust washers into the groove of the #3 main
• Insert
journal [B].

○Face the oil groove side of the thrust washer to the crankshaft.

NOTE

○The thrust washers are identical.
○If the thrust washer installed properly, the blue-painted
edges [C] are positioned as shown.
Front [D]

Connecting Rod Removal

• Refer to the Piston Removal.
Connecting Rod Installation
NOTICE
To minimize vibration, the connecting rods should
have the same weight mark.
Big End Cap [A]
Connecting Rod [B]
Weight Mark, Alphabet [C]
Diameter Mark [D] (“○” or No Mark)

NOTICE
If the connecting rods, big end bearing inserts, or
crankshaft are replaced with new ones, select the
bearing insert and check clearance with a plastigage (press gauge) before assembling engine to be
sure the correct bearing inserts are installed.
molybdenum disulfide oil solution to the inner sur• Apply
face of the upper and lower bearing inserts [A].
molybdenum disulfide oil solution to the threads [B]
• Apply
and seating surface [C] of the connecting rod big end nuts.
the inserts so that their nails [D] are on the same
• Install
side and fit them into the recess of the connecting rod and
cap.

NOTICE
Wrong application of oil and grease could cause
bearing damage.

CRANKSHAFT/TRANSMISSION 9-19
Crankshaft and Connecting Rods

○When installing the inserts [A], be careful not to damage

•
•

the insert surface with the edge of the connecting rod [B]
or the cap [C]. One way to install inserts is as follows.
Installation [D] to Cap
Installation [E] to Connecting Rod
Push [F]
Spare Dowel Pin [G]
Connecting Rod Bolts [H]
Remove debris and clean the surface of inserts.
Install the cap on the connecting rod, aligning the weight
and diameter marks.

each connecting rod on its original crankpin.
•○Install
The connecting rod big end is bolted using the “plastic
region fastening method”.
method precisely achieves the needed clamping
force without exceeding it unnecessarily, allowing the
use of thinner, lighter bolts further decreasing connecting
rod weight.
○There are two types of the plastic region fastening. One is
a bolt length measurement method and other is a rotation
angle method. Observe one of the following two, but the
bolt length measurement method is preferable because
this is a more reliable way to tighten the big end nuts.

○This

NOTICE
The connecting rod bolts are designed to stretch
when tightened. Never reuse the connecting rod
bolts. See the table below for correct bolt and nut
usage.

NOTICE
Be careful not to overtighten the nuts. The bolts
must be positioned on the seating surface correctly to prevent the bolt heads from hitting the
crankcase.

9-20 CRANKSHAFT/TRANSMISSION
Crankshaft and Connecting Rods
(1) Bolt Length Measurement Method
Be sure to clean the bolts, nuts, and connecting rods
thoroughly with a high flash-point solvent, because the
new connecting rods, bolts, and nuts are treated with an
anti-rust solution.

•

WARNING
Gasoline and low flash-point solvents can be
flammable and/or explosive and cause severe
burns. Clean the bolts, nuts, and connecting rods
in a well-ventilated area, and take care that there
are no sparks or flame anywhere near the working
area; this includes any appliance with a pilot light.
Do not use gasoline or a low flash-point solvent to
clean them.

NOTICE
Immediately dry the bolts and nuts with compressed air after cleaning. Clean and dry the bolts
and nuts completely.
new bolts and nuts in reused connecting rod.
• Install
If the connecting rod assembly was replaced, use the

•

bolts and nuts attached to the new connecting rod assembly.
Apply a small amount of molybdenum disulfide oil solution
to the following portions.
Threads [A] of Nuts and Bolts
Seating Surfaces [B] of Nuts and Connecting Rods

CRANKSHAFT/TRANSMISSION 9-21
Crankshaft and Connecting Rods
both bolt head and bolt tip with a punch as shown.
• Dent
Before
use a point micrometer to measure the
• length oftightening,
new connecting rod bolts and record the values

•
•

to find the bolt stretch.
Connecting Rod [A]
Dent here with a punch [B].
Nuts [C]
Fit micrometer pins into dents [D].
Tighten the big end nuts until the bolt elongation reaches
the length specified as follows.
Check the length of the connecting rod bolts.
If the stretch is more than the usable range, the bolt has
stretched too much. An overelongated bolt may break in
use.
Bolt Length after
tightening

Connecting Rod
Assy

New

Used

–

Bolt Length before
tightening

Bolt

Nut

Use the bolts
attached to
new con-rod.

Attached to
new con-rod

New

New

=

Bolt Stretch

Usable Range of
Connecting Rod
Bolt Stretch
0.24  0.34 mm
(0.0094  0.0134
in.)

Replace the
Replace the 0.24  0.34 mm
bolts with new nuts with new (0.0094  0.0134
ones.
ones.
in.)

(2) Rotation Angle Method
If you do not have a point micrometer, you may tighten
the nuts using the “Rotation Angle Method”.
Be sure to clean the bolts, nuts and connecting rods thoroughly with a high flash-point solvent, because the new
connecting rods, bolts and nuts are treated with an anti
-rust solution.