Snowmobile Yamaha FX10X, FX10RTX, FX10RTRX, FX10RTRAX, FX10MTX, FX10MTRX, FX10MTRAX. Manual - part 51

5-24

ENG

CAMSHAFTS

5. Install:

• Timing chain tensioner gasket 1
• Timing chain tensioner 2 

NOTE:

• Be sure to install the timing chain tensioner gas-

ket so that its section with the “L” mark 

a is pro-

truding from the lower left side of the timing chain
tensioner.

• The arrow mark 

b on the timing chain tensioner

should face up.

T

 

R

.

.

Timing chain tensioner bolt:

12 Nm (1.2 m · kg, 8.7 ft · lb)

1

L

a

2

b

New

6. Turn:

• Crankshaft

(several turns clockwise)

7. Inspect:

• “I” mark

Make sure the “I” mark 

a on the AC magneto

rotor is aligned with the stationary pointer 

b

on the AC magneto cover.

• Camshaft holes

Make sure the holes 

c in the cylinder #3 -

cam are aligned with the arrow marks 

d on

the camshaft caps. 
Out of alignment 

→ Adjust. 

Refer to the installation steps above.

b

a

d

c

d

c

8. Measure:

• Valve clearance 

Out of specification 

→ Adjust. 

Refer to “VALVE CLEARANCE ADJUST-
MENT” in CHAPTER 2.

5-25

ENG

CAMSHAFTS

9. Install:

• Cylinder head cover gasket
• Cylinder head cover

NOTE:

• Apply bond TB1541

®

 1 onto the mating surfaces

of the cylinder head cover and cylinder head
cover gasket.

• Apply Yamaha bond No. 1215 2 onto the mating

surfaces of the cylinder head cover gasket.

• Tighten the cylinder head cover bolts stages and

in a crisscross pattern.

T

 

R

.

.

Cylinder head cover bolt:

12 Nm (1.2 m · kg, 8.7 ft · lb)

Yamaha bond No. 1215:

90890-85505
(Three Bond No.1215

®

)

1

2

New

5-26

ENG

CYLINDER HEAD

CYLINDER HEAD

Order

Job name/Part name

Q’ty

Remarks

Cylinder head removal

Remove the parts in the order listed below.

Engine assembly

Refer to “ENGINE ASSEMBLY”.

Camshafts

Refer to “CAMSHAFTS”.

1

Oil delivery hose

1

2

Cylinder head

1

3

Cylinder head gasket

1

4

Dowel pin

2

For installation, reverse the removal proce-
dure.

E

(8)

2

1

4

3

New

É

Ê

È

New

4

20 Nm (2.0 m 

•

 kg, 14 ft 

•

 lb)

12 Nm (1.2 m 

•

 kg, 8.7 ft 

•

 lb)

È:   
É:   
Ê

:   

Specified angle 175 ~ 185˚

Final

25 Nm (2.5 m 

•

 kg, 18 ft 

•

 lb)

25 Nm (2.5 m 

•

 kg, 18 ft 

•

 lb)

1st

2nd

5-27

ENG

CYLINDER HEAD

REMOVAL

1. Remove:

• Cylinder head bolts

NOTE:

• Loosen the bolts in the proper sequence as

shown. 

• Loosen each bolt 1/2 of a turn at a time. After all

of the bolts are fully loosened, remove them. 

5

4

8

10

6

9

7

3

1

2

INSPECTION

1. Eliminate:

• Combustion chamber carbon deposits 

(with a rounded scraper)

NOTE:

Do not use a sharp instrument to avoid damaging
or scratching: 
• Spark plug bore threads 
• Valve seats 

2. Check:

• Cylinder head 

Damage/scratches 

→ Replace. 

• Cylinder head water jacket 

Mineral deposits/rust 

→ Eliminate.

3. Measure:

• Cylinder head warpage 

Out of specification 

→ Resurface the cylinder

head.

Measurement steps:

• Place a straightedge 1 and a thickness gauge

2 across the cylinder head.

• Measure the warpage.
• If the limit is exceeded, resurface the cylinder

head as follows.

• Place a 400 ~ 600 grit wet sandpaper on the

surface plate and resurface the cylinder head
using a figure-eight sanding pattern.

NOTE:

To ensure an even surface, rotate the cylinder head
several times. 

Maximum cylinder head warpage:

0.10 mm (0.0039 in)

1

2