Snowmobile Yamaha FX10X, FX10RTX, FX10RTRX, FX10RTRAX, FX10MTX, FX10MTRX, FX10MTRAX. Manual - part 59

5-56

ENG

CRANKCASE

6. Tighten:

• Crankcase bolts 9 ~ N 

NOTE:

Tighten the bolts in the order of the embossed
numbers on the crankcase.

7. Install:

• Primary sheave drive shaft assembly bolts

T

 

R

.

.

Crankcase bolt 9 ~ B: 

24 Nm (2.4 m · kg, 17 ft · lb)

Crankcase bolt C ~ N: 

12 Nm (1.2 m · kg, 8.7 ft · lb)

T

 

R

.

.

Primary sheave drive shaft assembly 
bolt:

12 Nm (1.2 m · kg, 8.7 ft · lb)

L

H F

C

9

0

D

E

I

G

J

K

N

M

A

B

8. Install:

• Engine mounting brackets 1 
• Engine mounting bracket bolts

NOTE:

When installing the engine mounting brackets,
make sure that the number on each side of the
upper crankcase is aligned with the identical num-
ber on the brackets.

T

 

R

.

.

Engine mounting bracket bolts:

25 Nm (2.5 m · kg, 18 ft · lb)

1

1

1

1

2

2

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ENG

CONNECTING RODS AND PISTONS

CONNECTING RODS AND PISTONS

Order

Job name/Part name

Q’ty

Remarks

Connecting rods and pistons removal

Remove the parts in the order listed below.

Crankcase

Separate.
Refer to “CRANKCASE”.

1

Connecting rod cap

3

2

Big end lower bearing

3

3

Piston pin clip

6

4

Piston pin

3

5

Piston

3

6

Connecting rod

3

7

Big end upper bearing

3

8

Top ring

3

9

2nd ring

3

10

Oil ring

3

For installation, reverse the removal proce-
dure.

M

E

M

M

M

E

E

E

E

10

9

8

4

3

3

7

6

1

2

5

New

New

New

New

New

New

È

È:   

Specified angle 115 ~ 125˚

20 Nm (2.0 m 

•

 kg, 14 ft 

•

 lb)

1st

Final

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ENG

CONNECTING RODS AND PISTONS

REMOVAL

1. Remove:

• Connecting rod cap 1 
• Big end bearings

NOTE:

Identify the position of each big end bearing so that
it can be reinstalled in its original place.

1

2. Remove:

• Piston pin clips 1 
• Piston pin 2 
• Piston 3 
• Connecting rod 4 

CAUTION:

Do not use a hammer to drive the piston pin
out.

NOTE:

• For reference during installation, put identification

mark on each piston crown.

• Before removing the piston pin, deburr the piston

pin clip groove and the piston pin bore area. If
both areas are deburred and the piston pin is still
difficult to remove, remove it with the piston pin
puller set 5.

Piston pin puller set:

90890-01304

Piston pin puller:

YU-01304

4

3

2

1

3. Remove:

• Top ring
• 2nd ring
• Oil ring

NOTE:

When removing a piston ring, open the end gap
with your fingers and lift the other side of the ring
over the piston crown.

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ENG

CONNECTING RODS AND PISTONS

INSPECTION

1. Inspect:

• Piston wall
• Cylinder wall

Vertical scratches 

→ Replace the crankcase,

and replace the piston and piston rings as a
set.

2. Measure:

• Piston-to-cylinder clearance

Measurement steps:
1st step:

• Measure cylinder bore “C” with the cylinder bore

gauge 1.

NOTE:

Measure cylinder bore “C” by taking side-to-side
and front-to-back measurements of the cylinder.
Then, find the average of the measurements.

Cylinder bore “C”

82.000 ~ 82.010 mm 

(3.2283 ~ 3.2287 in)

Taper limit “T”

0.050 mm (0.0020 in)

Out of round “R”

0.050 mm (0.0020 in)

• If out of specification, replace the crankcase,

and the piston and piston rings as a set.

“C” = maximum of D

1

 ~ D

6

“T” = maximum of D

1

 or D

2

 – maximum of D

5

 

or D

6

“R” = maximum of D

1

 D

3

 or D

5

 – maximum of 

D

2

 D

4

 or D

6