Snowmobile Yamaha Phazer PZ50W, PZ50GTW, PZ50FXW, PZ50MW, PZ50VTW, PZ50MPW. Manual - part 46

5-21

ENG

CAMSHAFTS

6. Remove:

• Intake camshaft sprocket 1 

(Use the special tool 2)

Rotor holding tool:

90890-01235, YU-01235

INSPECTION

1. Inspect:

• Camshaft lobes

Blue discoloration/pitting/scratches 

→ 

Replace the camshaft.

2. Measure:

• Camshaft lobe dimensions 

a and b 

Out of specification 

→ Replace the camshaft.

Camshaft dimensions:

Intake:
<Limit>:

a 30.350 mm (1.1949 in) 

b 22.510 mm (0.8862 in)

Exhaust:
<Limit>:

a 30.600 mm (1.2047 in)

b 22.493 mm (0.8856 in)

3. Measure:

• Camshaft runout

Out of specification 

→ Replace.

Camshaft runout:

0.03 mm (0.0012 in)

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ENG

CAMSHAFTS

4. Measure:

• Camshaft-journal-to-camshaft-cap clearance

Out of specification 

→ Measure the camshaft

journal diameter.

Measurement steps:

• Install the camshaft into the cylinder head (with-

out the dowel pins and camshaft caps).

• Position a strip of Plastigauge

®

  1 onto the

camshaft journal as shown.

• Install the dowel pins and camshaft caps.

NOTE:

• Tighten the camshaft cap bolts in stages and in a

crisscross pattern, working from the inner caps
out.

• Do not turn the camshaft when measuring the

camshaft journal-to-camshaft cap clearance with
the Plastigauge

®

.

• Remove the camshaft caps and then measure

the width of the Plastigauge

®

 1.

Camshaft-journal-to-camshaft-cap 
clearance:

0.028 ~ 0.062 mm
(0.0011 ~ 0.0024 in)

Camshaft cap bolt:

9 Nm (0.9 m · kg, 6.5 ft · lb)

1

1

5. Measure:

• Camshaft journal diameter 

a 

Out of specification 

→ Replace the camshaft.

Within specification 

→ Replace the cylinder

head and the camshaft caps as a set.

Camshaft journal diameter:

21.959 ~ 21.972 mm
(0.8645 ~ 0.8650 in)

6. Inspect:

• Camshaft sprocket

More than 1/4 tooth 

a wear → Replace the

camshaft sprockets and the timing chain as a
set.

a 1/4 tooth
b Correct
1 Timing chain roller
2 Camshaft sprocket

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CAMSHAFTS

7. Inspect:

• Decompression system

Inspection steps:

• Check that the decompressor lever pins 1

projects from the camshaft.

• Check that the decompressor cams 2 moves

smoothly.

8. Inspect:

• Timing chain guide (top side)

Damage/wear 

→ Replace the timing chain

guide.

2

1

1

9. Remove:

• Timing chain tensioner rod 1 
• Timing chain tensioner spring seat 2 
• Timing chain tensioner spring 3 
• Timing chain tensioner housing 5 

NOTE:

Squeeze the timing chain tensioner clip 4, and
then remove the timing chain tensioner springs and
timing chain tensioner rod.

10. Inspect:

• Timing chain tensioner housing
• Timing chain tensioner rod
• Timing chain tensioner spring seat
• Timing chain tensioner spring

Damage/wear 

→ Replace the as a set.

11. Assemble:

• Timing chain tensioner spring
• Timing chain tensioner spring seat
• Timing chain tensioner rod

NOTE:

Prior to installing the timing chain tensioner rod,
drain the engine oil from the timing chain tensioner
housing.

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CAMSHAFTS

Assembly steps:

• Install the timing chain tensioner spring, timing

chain tensioner spring seat, and timing chain
tensioner rod 1.

• Squeeze the timing chain tensioner clip 2, and

then push the timing chain tensioner rod 3 into
the timing chain tensioner housing.

NOTE:

Do not release the timing chain tensioner clip while
pushing the rod into the housing, otherwise the rod
may be ejected.

• Hook the clip 4 to the timing chain tensioner

rod 3.

NOTE:

Hook the timing chain tensioner rod pin 5 to the
center of the clip 4. After the installation, check
that the clip 4 can come off by its own weight by
pushing the timing chain tensioner rod 3 at the
position of installation.

12. Inspect:

• All parts

Damage/wear 

→ Replace the defective 

part(s).