Yamaha XMAX YP125R - Service manual > Camshaft (YP250R)

Removing the rocker arms and camshaft

Removing the rocker arms and camshaft

1. Straighten the lock plate tabs "a".

2. Remove:

• Lock plate "1"
• Camshaft retainer "2"

3. Remove:

• Rocker arm shafts
• Rocker arms

TIP

Remove the rocker arm shafts with the slide hammer bolt "1" and weight "2".

Slide hammer bolt 90890-01083

Slide hammer bolt 6 mm YU-01083-1

Weight 90890-01084 YU-01083-3

4. Remove:

• Camshaft "1"

TIP

Screw a M10 bolt "2" into the threaded end of the camshaft, and then pull out the camshaft.

Checking the camshaft

1. Check:

• Camshaft lobes

Blue discoloration/pitting/scratches → Replace the camshaft.

2. Measure:

• Camshaft lobe dimensions "a" and "b"

Out of specification → Replace the camshaft.

Camshaft lobe dimensions Intake A 37.051-37.151 mm (1.4587- 1.4626 in)

Limit 36.950 mm (1.4547 in)

Intake B 30.074-30.174 mm (1.1840- 1.1880 in)

Limit 29.974 mm (1.1801 in)

Exhaust A 37.053-37.153 mm (1.4588- 1.4627 in)

Limit 36.953 mm (1.4548 in)

Exhaust B 30.091-30.191 mm (1.1847- 1.1886 in)

Limit 29.991 mm (1.1807 in)

3. Check:

• Camshaft oil passage

Obstruction → Blow out with compressed air.

Checking the rocker arms and rocker arm shafts

The following procedure applies to all of the rocker arms and rocker arm shafts.

1. Check:

• Rocker arm

Damage/wear → Replace.

2. Check:

• Rocker arm shaft

Blue discoloration/excessive wear/pitting/ scratches → Replace or check the lubrication system.

3. Measure:

• Rocker arm inside diameter "a"

Out of specification → Replace.

Rocker arm inside diameter 12.000-12.018 mm (0.4724- 0.4731 in)

Limit 12.030 mm (0.4736 in)

4. Measure:

• Rocker arm shaft outside diameter "a"

Out of specification → Replace.

Rocker arm shaft outside diameter 11.981-11.991 mm (0.4717- 0.4721 in)

Limit 11.950 mm (0.4705 in)

5. Calculate:

• Rocker-arm-to-rocker-arm-shaft clearance

TIP

Calculate the clearance by subtracting the rocker arm shaft outside diameter from the rocker arm inside diameter.

Out of specification → Replace the defective part(s).

Rocker-arm-to-rocker-arm-shaft clearance 0.009-0.037 mm (0.0004-0.0015 in)

Limit 0.080 mm (0.0031 in)

Installing the camshaft and rocker arms

1. Lubricate:

• Camshaft

Recommended lubricant

Camshaft Molybdenum disulfide grease

Camshaft bearing

Engine oil

2. Lubricate:

• Rocker arms
• Rocker arm shafts

Recommended lubricant

Rocker arm inner surface

Molybdenum disulfide grease

Rocker arm shaft

Engine oil

3. Install:

• Exhaust rocker arm
• Exhaust rocker arm shaf

TIP

Make sure the exhaust rocker arm shaft is completely pushed into the cylinder head.

4. Install:

• Intake rocker arm
• Intake rocker arm shaft "1"

TIP

Insert a guide stud (8 mm) "2" into the stud-bolt hole in the cylinder head and install the intake rocker arm shaft as shown.

NOTICE

Make sure the threaded part of the rocker arm shaft faces out.

5. Install:

• Camshaft retainer "1"
• Lock plate "2"

Camshaft retainer bolt 8 Nm (0.8 m*kgf, 5.8 ft*lbf)

TIP

Bend the lock plate tabs along a flat side of the bolts "3".

See also: