Snowmobile Yamaha Phazer PZ50 (2007-2008 year). Instruction - part 50

 

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Snowmobile Yamaha Phazer PZ50 (2007-2008 year). Instruction - part 50

 

 

5-37

ENG

VALVES AND VALVE SPRINGS

• Install the valve into the cylinder head.
• Turn the valve until the valve face and valve

seat are evenly polished, then clean off all of
the lapping compound.

NOTE:

For the best lapping results, lightly tap the valve
seat while rotating the valve back and forth
between your hands. 

• Apply a fine lapping compound to the valve face

and repeat the above steps. 

• After every lapping procedure, be sure to clean

off all of the lapping compound from the valve
face and valve seat. 

• Apply Mechanic’s blueing dye (Dykem) 

b onto

the valve face. 

• Install the valve into the cylinder head. 
• Press the valve through the valve guide and

onto the valve seat to make a clear impression. 

• Measure the valve seat width 

c again. If the

valve seat width is out of specification, reface
and lap the valve seat. 

11. Measure:

• Valve spring free length 

Out of specification 

→ Replace the valve

spring.

Valve spring free length:

Intake:

36.51 mm (1.44 in)
<Limit>: 34.68 mm (1.37 in)

Exhaust:

37.92 mm (1.49 in)
<Limit>: 36.02 mm (1.42 in)

5-38

ENG

VALVES AND VALVE SPRINGS

12. Measure:

• Compressed valve spring force 

Out of specification 

→ Replace the valve

spring.

b Installed length

Compressed valve spring force 
(installed):

Intake:

120.7 ~ 138.9 N at 30.13 mm
(12.3 ~ 14.2 kg at 30.13 mm, 
27.1 ~ 31.2 lb at 1.19 in)

Exhaust:

150.6 ~ 173.2 N at 30.50 mm
(15.4 ~ 17.7 kg at 30.50 mm, 
33.9 ~ 38.9 lb at 1.20 in)

13. Measure:

• Valve spring tilt 

Out of specification 

→ Replace the valve

spring.

Maximum valve spring tilt:

Intake:

2.5°/1.6 mm (0.06 in)

Exhaust:

2.5°/1.7 mm (0.07 in)

14. Inspect:

• Valve lifter

Damage/scratches 

→ Replace the valve lift-

ers and cylinder head.

INSTALLATION

1. Deburr:

• Valve stem end

(with an oil stone)

5-39

ENG

VALVES AND VALVE SPRINGS

2. Lubricate:

• Valve stem 1 
• Valve stem seal 2 

(with the recommended lubricant)

Recommended lubricant:

Molybdenum disulfide oil

3. Install:

• Lower spring seat 1 
• Valve stem seal 2 
• Valve 3 
• Valve spring 4 
• Upper spring seat 5 

(into the cylinder head)

NOTE:

• Make sure each valve is installed in its original

place. 

• Install the valve spring with the larger pitch 

a fac-

ing up. 

b Smaller pitch

4. Install:

• Valve cotters 1 

NOTE:

Install the valve cotters by compressing the valve
spring with the valve spring compressor 2 and
attachment 3. 

Valve spring compressor:

90890-04019, YM-04019

Valve spring compressor attach-
ment:

Intake valve:

90890-04114, YM-04114

Exhaust valve:

90890-04108, YM-04108

2

3

1

5-40

ENG

VALVES AND VALVE SPRINGS

5. To secure the valve cotters onto the valve stem,

lightly tap the valve tip with a soft-face hammer.

CAUTION:

Hitting the valve tip with excessive force could
damage the valve. 

6. Lubricate: 

• Valve pad
• Valve lifter

(with the recommended lubricant)

7. Install:

• Valve pad
• Valve lifter

NOTE:

• The valve lifter must move smoothly when rotated

with a finger. 

• Each valve lifter and valve pad must be rein-

stalled in its original position. 

Recommended lubricant:

Molybdenum disulfide oil

 

 

 

 

 

 

 

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