Snowmobile Yamaha FX10X, FX10RTX, FX10RTRX, FX10RTRAX, FX10MTX, FX10MTRX, FX10MTRAX. Manual - part 61

5-64

ENG

CONNECTING RODS AND PISTONS

• Tighten the connecting rod nuts.

Refer to “INSTALLATION” in “CONNECTING
RODS AND PISTONS” on page 5-65.

• Remove the connecting rod and big end bear-

ings.

• Measure the compressed Plastigauge

®

 width 

e

on the crankshaft pin.
If the clearance is out of specification, select
replacement big end bearings.

e

11. Select:

• Big end bearings (P1 ~ P3)

NOTE:

• The numbers 

È stamped into the crankshaft web

and the numbers 1 on the connecting rods are
used to determine the replacement big end bear-
ing sizes.

• “P1” ~ “P3” refer to the bearings shown in the

crankshaft illustration.

P1

P2

P3

Selection of bearings:

• For example, if the connecting rod “P1” and the

crankshaft web “P1” numbers are “6” and “2”
respectively, then the bearing size for “P1” is:

Bearing size for “P1”:

“P1” (connecting rod) – “P1” (crankshaft 
web) – 1 = 6 – 2 – 1 = 3 (brown)

BIG END BEARING COLOR CODE

0

white

1

blue

2

black

3

brown

4

green

5

yellow

2 2 2 1

3 2 2

P1

P3

P2

È

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ENG

CONNECTING RODS AND PISTONS

INSTALLATION

1. Install:

• Top ring 1 
• 2nd ring 2 
• Upper oil ring rail 3 
• Oil ring expander 4 
• Lower oil ring rail 5 

NOTE:

Be sure to install the piston rings so that the manu-
facturer marks 

a face up.

2. Install:

• Piston 1 

(onto the respective connecting rod 2)

• Piston pin 3 
• Piston pin clips 4

NOTE:

• Apply engine oil onto the piston pin.
• Make sure that the “Y” mark 

a on the connecting

rod faces left when the punch mark 

b on the pis-

ton is pointing up. Refer to the illustration.

• Install the piston pin clips, so that the clip ends

are 3 mm (0.12 in) 

c or more from the cutout in

the piston.

• Reinstall each piston into its original cylinder

(numbering order starting from the left: #1 to #3).

2

1

3

4

a

b

4

c

New

3. Offset:

• Piston ring end gaps

a Top ring
b 2nd ring
c Upper oil ring rail
d Oil ring expander
e Lower oil ring rail
È Exhaust side

be

ad

c

È

90˚

90˚

45˚

5-66

ENG

CONNECTING RODS AND PISTONS

4. Lubricate:

• Piston
• Piston rings
• Cylinder

(with the recommended lubricant)

5. Lubricate:

• Bolt threads
• Nut seats

(with the recommended lubricant)

6. Lubricate:

• Crankshaft pins
• Big end bearings
• Connecting rod inner surface

(with the recommended lubricant)

7. Install:

• Big end bearings
• Connecting rod assembly 1 

(into the cylinder and onto the crankshaft pin).

• Connecting rod cap

(onto the connecting rod)

NOTE:

• Align the projections on the big end bearings with

the notches in the connecting rods and connect-
ing rod caps.

• Be sure to reinstall each big end bearing in its

original place.

• While compressing the piston rings with piston

ring compressor 2, install the connecting rod
assembly into the cylinder with the other hand.

• Make sure that the “Y” marks 

a on the connect-

ing rods face towards the right side (AC magneto
rotor side) of the crankshaft.

• Make sure that the characters 

b on both the con-

necting rod and connecting rod cap are aligned.

Recommended lubricant:

Engine oil

Recommended lubricant:

Molybdenum disulfide grease

Recommended lubricant:

Engine oil

Piston ring compressor:

90890-05158, YM-08037

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ENG

CONNECTING RODS AND PISTONS

8. Align:

• Bolt heads

(with the connecting rod caps)

9. Tighten:

• Connecting rod nuts

WARNING

Replace the connecting rod bolts and nuts with
new ones.

CAUTION:

Tighten the connecting rod bolts using the
plastic-region tightening angle method. Always
install new bolts and nuts.

• Clean the connecting rod bolts and nuts.
• Tighten the connecting rod nuts.

• Put a mark 

a on the corner of the connecting

rod nut 1 and the connecting rod 2.

• Tighten the connecting rod nut further to

reach the specified angle (115 ~ 125°).

WARNING

When the nut is tightened more than the speci-
fied angle, do not loosen the nut and then
retighten it.
Replace the bolt and nut with a new one and
perform the procedure again.

CAUTION:

• Do not use a torque wrench to tighten the nut

to the specified angle.

• Tighten the nut until it is at the specified

angles.

NOTE:

When using a hexagonal nut, note that the angle
from one corner to another is 60°.

T

 

R

.

.

Connecting rod nut:

1st:

20 Nm (2.0 m · kg, 14 ft · lb)

T

 

R

.

.

Connecting rod nut:

Final:

Specified angle 115 ~ 125°