Snowmobile Yamaha FX10X, FX10RTX, FX10RTRX, FX10RTRAX, FX10MTX, FX10MTRX, FX10MTRAX. Manual - part 52

5-28

ENG

CYLINDER HEAD

INSTALLATION

1. Install:

• Cylinder head

NOTE:

Pass the timing chain through the timing chain cav-
ity. 

2. Tighten:

• Cylinder head bolts (M10)

NOTE:

The tightening procedure of the cylinder head bolts
is angle controlled, therefore tighten the bolts using
the following procedure.

Tightening steps:

• Lubricate the cylinder head bolts and washers

with engine oil.

• Install the washers and cylinder head bolts.
• Tighten the cylinder head bolts in the proper

tightening sequence as shown.

• Loosen and retighten the cylinder head bolts in

the proper tightening sequence as shown.

T

 

R

.

.

Cylinder head bolt (M10):

1st:

25 Nm (2.5 m · kg, 18 ft · lb) 

T

 

R

.

.

Cylinder head bolt (M10):

2nd:

25 Nm (2.5 m · kg, 18 ft · lb) 

6

7

3

1

5

2

4

8

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ENG

CYLINDER HEAD

• Tighten the cylinder head bolts further to reach

the specified angle 175 ~  185° in the proper
tightening sequence as shown.

WARNING

When the bolts are tightened more than the
specified angle, do not loosen the bolt and then
retighten it.
Replace the bolt with a new one and perform
the procedure again.

CAUTION:

• Do not use a torque wrench to tighten the bolt

to the specified angle.

• Tighten the bolt until it is at the specified

angle.

NOTE:

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

T

 

R

.

.

Cylinder head bolt (M10):

Final:

Specified angle 175 ~ 185°

3. Tighten:

• Cylinder head bolts (M6) 1 

T

 

R

.

.

Cylinder head bolt:

12 Nm (1.2 m · kg, 8.7 ft · lb)

1

5-30

ENG

VALVES AND VALVE SPRINGS

VALVES AND VALVE SPRINGS

Order

Job name/Part name

Q’ty

Remarks

Valves and valve springs removal

Remove the parts in the order listed below.

Cylinder head

Refer to “CYLINDER HEAD”.

1

Valve lifter

12

2

Valve pad

12

3

Valve cotter

24

4

Upper spring seat

12

5

Valve spring

12

6

Intake valve

6

7

Exhaust valve

6

8

Valve stem seal

12

9

Lower spring seat

12

10

Valve guide

12

For installation, reverse the removal proce-
dure.

M

M

M

M

M

New

8

5

4

3

2

1

3

9

New

10

6

10

7

9

8

5

4

3

2

3

1

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ENG

VALVES AND VALVE SPRINGS

REMOVAL

The following procedure applies to all of the valves
and related components.

NOTE:

Before removing the internal parts of the cylinder
head (e.g., valves, valve springs, valve seats),
make sure the valves properly seal. 

1. Remove:

• Valve lifter 1 
• Valve pad 2 

NOTE:

Make a note of the position of each valve lifter and
valve pad so that they can be reinstalled in their
original place. 

2. Inspect:

• Valve

(for leakage) 
Leakage at the valve seat 

→ Check the valve

face, valve seat, and valve seat width.

Inspection steps:

• Pour a clean solvent 

a into the intake and

exhaust ports. 

• Check that the valves properly seal.

NOTE:

There should be no leakage at the valve seat 1. 

3. Remove:

• Valve cotters

NOTE:

Remove the valve cotters by compressing the valve
spring with the valve spring compressor 1 and
valve spring compressor attachment 2. 

Valve spring compressor:

90890-04019, YM-04019

Valve spring compressor attach-
ment:

90890-04114

Valve spring compressor adapter 
19.5 mm:

YM-04114