Snowmobile Yamaha Phazer PZ50W, PZ50GTW, PZ50FXW, PZ50MW, PZ50VTW, PZ50MPW. Manual - part 6

2-12

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ADJ

VALVE CLEARANCE ADJUSTMENT

• Install the new valve pad 1 and the valve lifter

2.

NOTE:

• Apply molybdenum disulfide oil to the valve pad

and the valve lifter.

• The valve lifter must turn smoothly when rotated

by hand.

• Install the valve lifter and the valve pad in the cor-

rect place.

• Install the exhaust and intake camshafts, timing

chain and camshaft caps.

NOTE:

• Refer to “CAMSHAFTS” in CHAPTER 5.
• Lubricate the camshaft caps, camshaft lobes,

camshaft journals and camshaft cap bolts.

• Align the camshaft marks with the camshaft cap

marks.

• Rotate the crankshaft counterclockwise several

turns to seat the parts.

• Measure the valve clearance again.
• If the valve clearance is still out of specification,

repeat all of the valve clearance adjustment
steps until the specified clearance is obtained.

7. Install:

• Crankshaft end accessing screw
• Timing mark accessing screw

8. Install:

• Cylinder head cover

Refer to “CAMSHAFTS” in CHAPTER 5.

9. Install:

• All removed parts

NOTE:

For installation, reverse the removal procedure.
Note the following points.

T

 

R

.

.

Camshaft cap bolt:

9 Nm (0.9 m · kg, 6.5 ft · lb)

2

1

2-13

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THROTTLE BODY SYNCHRONIZATION

THROTTLE BODY SYNCHRONIZATION

NOTE:

Prior to synchronizing the throttle bodies, the valve
clearance and the engine idle speed should be
properly adjusted.

1. Remove:

• Headlight assembly (PZ50/PZ50GT/PZ50FX/

PZ50M)

• Air filter case assembly

Refer to “COWLINGS” in CHAPTER 3.

2. Remove:

• Vacuum cap 1 

1

3. Install:

• Vacuum gauge 1 

4. Install:

• Air filter case

Refer to “COWLINGS” in CHAPTER 3.

5. Start the engine and let it warm up for several

minutes.

6. Inspect:

• Engine idle speed

Out of specification 

→

 Adjust.

Refer to “ENGINE IDLE SPEED ADJUST-
MENT”.

7. Adjust:

• Throttle body synchronization

Vacuum gauge:

90890-03094, YU-44456

Engine idle speed:

1,700 ~ 1,900 r/min

1

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THROTTLE BODY SYNCHRONIZATION/

ENGINE IDLE SPEED ADJUSTMENT

Adjustment steps:

• Synchronize throttle body #1 and throttle body

#2 by turning the synchronizing screws 1 in
either direction until both gauges read the
same.

NOTE:

After each step, rev the engine two or three times,
each time for less than a second, and check the
synchronization again.

NOTE:

The difference in vacuum pressure between two
throttle bodies should not exceed 1.33 kPa
(0.01 kg/cm

2

, 0.19 psi).

8. Measure:

• Engine idle speed

Out of specification 

→ Adjust.

Make sure that the vacuum pressure is within
specification.

9. Stop the engine and remove the measuring

equipment.

10. Adjust:

• Throttle cable free play

Refer to “THROTTLE CABLE FREE PLAY
ADJUSTMENT”.

Vacuum pressure at engine idling 
speed:

20.27 ~ 22.93 kPa
(0.20 ~ 0.23 kg/cm

2

, 2.88 ~ 3.26 psi)

1

ENGINE IDLE SPEED ADJUSTMENT

NOTE:

Prior to adjusting the engine idling speed, the throt-
tle body synchronization should be adjusted prop-
erly, the air filter should be clean, and the engine
should have adequate compression.

1. Start the engine and let it warm up for several

minutes.

2. Measure:

• Engine idle speed

Out of specification 

→ Adjust.

Engine idle speed:

1,700 ~ 1,900 r/min

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ENGINE IDLE SPEED ADJUSTMENT/

THROTTLE CABLE FREE PLAY ADJUSTMENT

3. Adjust:

• Engine idle speed

Adjustment steps:

• Remove the rubber cap 1. 
• Turn the idle adjusting screw 2 in or out until

the specified engine idle speed is obtained.

NOTE:

After adjusting the engine idle speed, the throttle
cable free play should be adjusted.

Turning in 

→ Idle speed is increased.

Turning out 

→ Idle speed is decreased.

1

2

THROTTLE CABLE FREE PLAY 
ADJUSTMENT

NOTE:

• Before adjusting the throttle cable free play, the

engine idle speed should be adjusted.

• Adjust the throttle cable free play while the cable

is in the cable guide.

1. Measure:

• Throttle cable free play 

a 

Out of specification 

→ Adjust.

2. Adjust:

• Throttle cable free play

Throttle cable free play:

2.0 ~ 3.0 mm (0.08 ~ 0.12 in)

a

Throttle body side adjustment steps:

• Remove the air filter case.

Refer to “COWLINGS” in CHAPTER 3.

• Loosen the locknut 1.
• Turn the adjusting nut 2 in or out until the spec-

ified free play is obtained.

Turning in 

→ Free play is increased.

Turning out 

→ Free play is decreased.

2

1