•

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.

9-22 CRANKSHAFT/TRANSMISSION
Crankshaft and Connecting Rods
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

tighten the nuts with 20 N·m (2.0 kgf·m, 15 ft·lb) of
• First,
torque.
tighten the nuts 150°.
•○Next,
Mark [A] the connecting rod big end caps and nuts so that
nuts can be turned 150° [B] properly.
Connecting
Rod Assy
New

Used

Bolt

Nut

Attached to
new con-rod

Attached to
new con-rod

New

New

Replace the
bolts with
new ones

Torque + Angle
N·m (kgf·m, ft·lb)
20 (2.0, 15) + 150°

Replace the
nuts with new 20 (2.0, 15) + 150°
ones

○The nuts can be tightened by using a torque angle gauge
[A].

Crankshaft/Connecting Rod Cleaning

removing the connecting rods from the crankshaft,
• After
clean them with a high flash-point solvent.
the crankshaft oil passages with compressed air to
• Blow
remove any foreign particles or residue that may have
accumulated in the passages.

CRANKSHAFT/TRANSMISSION 9-23
Crankshaft and Connecting Rods
Connecting Rod Bend Inspection

the connecting rod big end bearing inserts, and
• Remove
reinstall the connecting rod big end cap.
an arbor [A] of the same diameter as the connect• Select
ing rod big end, and insert the arbor through the connect-

•
•
•

ing rod big end.
Select an arbor of the same diameter as the piston pin
and at least 100 mm (3.94 in.) long, and insert the arbor
[B] through the connecting rod small end.
On a surface plate, set the big-end arbor on V block [C].
With the connecting rod held vertically, use a height
gauge to measure the difference in the height of the
arbor above the surface plate over a 100 mm (3.94 in.)
length to determine the amount of connecting rod bend.
If the connecting rod bend exceeds the service limit, the
connecting rod must be replaced.
Connecting Rod Bend
Service Limit: TIR 0.2/100 mm (0.008/3.94 in.)

Connecting Rod Twist Inspection

the big-end arbor [A] still on V block [B], hold the
• With
connecting rod horizontally and measure the amount that
the arbor [C] varies from being paralleled with the surface
plate over a 100 mm (3.94 in.) length of the arbor to determine the amount of connecting rod twist.
If the connecting rod twist exceeds the service limit, the
connecting rod must be replaced.
Connecting Rod Twist
Service Limit: TIR 0.2/100 mm (0.008/3.94 in.)

Connecting Rod Big End Side Clearance
Inspection

connecting rod big end side clearance.
•○Measure
Insert a thickness gauge [A] between the big end and either crank web to determine clearance.
Connecting Rod Big End Side Clearance
Standard:
0.13  0.38 mm (0.0051  0.0150 in.)
Service Limit: 0.6 mm (0.02 in.)

If the clearance exceeds the service limit, replace the connecting rod with a new one and then check the clearance
again. If the clearance is too large after connecting rod
replacement, the crankshaft also must be replaced.

Connecting Rod Big End Bearing Insert/Crankpin
Wear Inspection

the connecting rod big end (see Connecting Rod
• Remove
Removal).
strips of plastigage to crankpin width. Place a strip
• Cut
on the crankpin parallel to the crankshaft installed in the

•

correct position.
Tighten the connecting rod big end nuts to the specified
torque (see Connecting Rod Installation).

NOTE

○Do not move the connecting rod and crankshaft during
clearance measurement.

9-24 CRANKSHAFT/TRANSMISSION
Crankshaft and Connecting Rods
the connecting rod big end again, measure each
• Remove
clearance between the bearing insert and crankpin [A] using plastigage (press gauge) [B].

NOTICE
After measurement, replace the connecting rod
bolts and nuts.
Connecting Rod Big End Bearing Insert/Crankpin
Clearance
Standard:
0.030  0.060 mm (0.0012  0.0024 in.)
Service Limit: 0.10 mm (0.0039 in.)

If the clearance is within the standard, no bearing replacement is required.
If the clearance is between 0.061 mm (0.0024 in.) and
the service limit (0.10 mm, 0.0039 in.), replace the bearing inserts [A] with inserts painted blue [B]. Check insert/crankpin clearance with the plastigage. The clearance may exceed the standard slightly, but it must not be
less than the minimum in order to avoid bearing seizure.
If the clearance exceeds the service limit, measure the
diameter of the crankpins.
Crankpin Diameter
Standard:
34.484  34.500 mm (1.3576  1.3583 in.)
Service Limit: 34.47 mm (1.357 in.)

If any crankpin has worn past the service limit, replace the
crankshaft with a new one.
If the measured crankpin diameters [A] are not less than
the service limit, but do not coincide with the original diameter markings [B] on the crankshaft, make new marks
on it.
Crankpin Diameter Marks
None 34.484  34.492 mm (1.3576  1.35795 in.)

○

34.493  34.500 mm (1.35799  1.3583 in.)

: Crankpin Diameter Marks (“○” or No Mark)
the connecting rod big end inside diameter, and
• Measure
mark each connecting rod big end in accordance with the

•

inside diameter.
Tighten the connecting rod big end nuts to the specified
torque (see Connecting Rod Installation).

NOTE

○The mark already on the big end should almost coincide
with the measurement.

CRANKSHAFT/TRANSMISSION 9-25
Crankshaft and Connecting Rods
Connecting Rod Big End Inside Diameter Marks
None 37.500  37.508 mm (1.4764  1.47669 in.)

○

37.509  37.516 mm (1.47673  1.4770 in.)

Big End Cap [A]
Connecting Rod [B]
Weight Mark, Alphabet [C]
Diameter Mark [D] (“○” or No Mark)

the proper bearing insert [A] in accordance with the
• Select
combination of the connecting rod and crankshaft coding.
Size Color [B]

Connecting Rod Big
End Inside Diameter
Marking

Bearing Insert

Crankpin Diameter
Marking

Size Color

Part Number

None

○

Brown

92139-0855

None

None

○
○

○

Black

92139-0854

None

Blue

92139-0853

the new inserts in the connecting rod and check
• Install
insert/crankpin clearance with the plastigage.

Crankshaft Side Clearance Inspection

a thickness gauge [A] between the thrust washer
• Insert
[B] on the crankcase and the crank web [C] at the #3 main
journal to determine clearance.
If the clearance exceeds the service limit, replace the
thrust washers as a set and check the width of the crankshaft #3 main journal.
Crankshaft Side Clearance
Standard:
0.05  0.25 mm (0.0020  0.0098 in.)
Service Limit: 0.45 mm (0.0177 in.)

9-26 CRANKSHAFT/TRANSMISSION
Crankshaft and Connecting Rods
the width [A] of the crankshaft #3 main journal
• Measure
[B].
If the measurement exceeds the standard, replace the
crankshaft.
Crankshaft #3 Main Journal Width
Standard:
23.49  23.54 mm (0.925  0.927 in.)

Crankshaft Runout Inspection

the crankshaft runout.
• Measure
If the measurement exceeds the service limit, replace the
crankshaft.
Crankshaft Runout
Standard:
TIR 0.03 mm (0.0012 in.) or less
Service Limit: TIR 0.08 mm (0.0032 in.)

Crankshaft Main Bearing Insert/Journal Wear
Inspection

the crankcase (see Crankcase Splitting).
• Split
Cut
strips
of plastigage to journal width.
• Place a strip
each journal parallel to the crankshaft
• installed in theoncorrect
position.
the crankcase bolts to the specified torque (see
• Tighten
Crankcase Assembly).

NOTE

○Do not turn the crankshaft during clearance measurement.
○Journal clearance less than 0.025 mm (0.00098 in.) can
not be measured by plastigage [A], however, using genuine parts maintains the minimum standard clearance.
the crankcase again, measure each clearance be• Split
tween the bearing insert and journal [B] using plastigage
(press gauge).
Crankshaft Main Bearing Insert/Journal Clearance
Standard:
0.014  0.038 mm (0.0006  0.0015 in.)
Service Limit: 0.07 mm (0.0028 in.)

If the clearance is within the standard, no bearing replacement is required.
If the clearance is between 0.035 mm (0.0014 in.) and the
service limit (0.06 mm, 0.0024 in.), replace the bearing inserts [A] with inserts painted blue [B]. Check insert/journal
clearance with the plastigage. The clearance may exceed
the standard slightly, but it must not be less than the minimum in order to avoid bearing seizure.
If the clearance exceeds the service limit, measure the
diameter of the crankshaft main journal.

CRANKSHAFT/TRANSMISSION 9-27
Crankshaft and Connecting Rods
Crankshaft Main Journal Diameter
Standard:
34.984  35.000 mm (1.3773  1.3780 in.)
Service Limit: 34.96 mm (1.3764 in.)

If any journal has worn past the service limit, replace the
crankshaft with a new one.
If the measured journal diameters [A] are not less than the
service limit, but do not coincide with the original diameter
markings [B] on the crankshaft, make new marks on it.
Crankshaft Main Journal Diameter Marks
None 34.984  34.992 mm (1.3773  1.3776 in.)
34.993  35.000 mm (1.3777  1.3780 in.)

1

□: Crankshaft Main Journal Diameter Marks (“1” or No
Mark)
the main bearing inside diameter, and mark the
• Measure
upper crankcase half in accordance with the inside diameter.
[A]: Crankcase Main Bearing Inside Diameter Marks, “○”
or no mark.
the crankcase bolts to the specified torque (see
• Tighten
Crankcase Assembly).

NOTE

○The mark already on the upper crankcase half should
almost coincide with the measurement.
Crankcase Main Bearing Inside Diameter Marks
38.000  38.008 mm (1.4961  1.49637 in.)

○

None 38.009  38.016 mm (1.49641  1.4967 in.)

the proper bearing insert [A] in accordance with the
• Select
combination of the crankcase and crankshaft coding.
Size Color [B]

•

Crankcase Main
Bearing Inside
Diameter Marking

Crankshaft Main
Journal Diameter
Marking

Bearing Insert
Size Color

Part Number (Journal Nos.*)

○

1

Brown

92139-0300 (1, 3, 5)
92139-0303 (2, 4)

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.
Install the new inserts in the crankcase halves and check
insert/journal clearance with the plastigage.

9-28 CRANKSHAFT/TRANSMISSION
Pistons
Piston Removal

• Remove:
Crankshaft (see Crankshaft Removal)
Remove
the piston together with the connecting rod from
• the cylinder
head side.
NOTICE
Discard the connecting rod bolts and nuts. To prevent damage to the crankpin surfaces, do not allow the connecting rod bolts to bump against the
crankpins.

• Remove the piston pin snap ring [A] (Both Sides).

the piston pin puller assembly [A], remove the pis• Using
ton pin.
Special Tool - Piston Pin Puller Assembly: 57001-910

• Remove the piston from the connecting rod.

spread the ring opening with your thumbs and
• Carefully
then push up on the opposite side of the ring [A] to remove

•

it.
Remove the 3-piece oil ring with your thumbs in the same
manner.

CRANKSHAFT/TRANSMISSION 9-29
Pistons
Piston Installation

molybdenum disulfide oil solution to the oil ring ex• Apply
pander, and install the oil ring expander [A] in the bottom
piston ring groove so the ends [B] not butt together.
Apply molybdenum disulfide oil solution to the oil ring steel
rails, and install the oil ring steel rails, one above the expander and one below it.
○Spread the rail with your thumbs, but only enough to fit
the rail over the piston.
○Release the rail into the bottom piston ring groove.

•

NOTE

○The oil ring rails have no “top” or “bottom”.
molybdenum disulfide oil solution to the piston
• Apply
rings.

NOTE

○Do not mix up the top and second ring.
the top ring [A] so that the “1T” mark [B] faces up.
• Install
Install
the
second ring [C] so that the “T2” mark [D] faces
• up.

molybdenum disulfide oil solution to the piston pin
• Apply
and piston journal.

NOTE

○If a new piston is used, use new piston rings.
a new piston pin snap ring into the side of the piston
• Fit
so that the ring opening [A] does not coincide with the slit
[B] of the piston pin hole.
○When installing the piston pin snap ring, compress it only
enough to install it and no more.

NOTICE
Do not reuse snap rings, as removal weakens and
deforms them. They could fall out and score the
cylinder wall.
piston ring openings must be positioned as shown.
• The
The openings of the oil ring steel rails must be about 30
 40° of angle from the opening of the top ring.
Top Ring [A]
Second Ring [B]
Oil Ring Steel Rails [C]
Oil Ring Expander [D]
Hollow [E]
30  40° [F]

9-30 CRANKSHAFT/TRANSMISSION
Pistons
molybdenum disulfide oil solution to the cylinder
• Apply
bore and piston skirt.
the piston ring compressor assembly to install the
• Using
piston from the cylinder head side.
Special Tools - Piston Ring Compressor Grip: 57001-1095
Piston Ring Compressor Belt, 67  79:
57001-1097

the piston so that the hollow mark [A] turns from
• Rotate
the exhaust side [B] to the right by 90 degrees [C] and

•
•

insert the piston until immediately before the piston ring
compressor belt [D] touches the cylinder block.
Rotate the piston so that the hollow mark [E] turns to the
exhaust side [F] and insert the piston.
Install:
Crankshaft (see Crankshaft Installation)
Connecting Rod Big End Caps (see Connecting Rod Installation)

Cylinder (Upper Crankcase) Wear Inspection

the crankcase (see Crankcase Splitting).
• Split
the pistons (see Piston Removal).
• Remove
Assemble
the cylinder (upper crankcase) [A], the cylinder
• head [B] and
the cylinder head gasket [C].
Tighten
the
cylinder
bolts (see Cylinder Head Instal• lation in the Engine head
Top End chapter).
Put
the
crankcase
upside
down.
•
there is a difference in cylinder wear (upper
• Since
crankcase) in different directions, take a side-to-side and
a front-to-back measurement at each of the two locations
(total of four measurements) as shown.
If any of the cylinder inside diameter measurements exceeds the service limit, replace the crankcase.
10 mm (0.39 in.) [A]
60 mm (2.36 in.) [B]
Cylinder (Upper Crankcase) Inside Diameter
Standard:
75.994  76.006 mm (2.9919  2.9924 in.)
Service Limit: 76.09 mm (2.996 in.)

Piston Wear Inspection