Removing The Rocker Arms And Camshaft; Checking The Camshaft - Yamaha 2009 YFM25RY Service Manual

EAS23770
REMOVING THE ROCKER ARMS AND
CAMSHAFT
1. Loosen:
• Locknut "1"
• Valve clearance adjusting screw "2"
2. Remove:
• Lock plate "3"
3. Remove:
• Camshaft "1"
• Bearing "2"
TIP
Screw 10 mm (0.396 in) bolt "3" into the
threaded end of the camshaft and then pull out
the camshaft.
4. Remove:
• Intake rocker arm shaft
• Exhaust rocker arm shaft
• Intake rocker arm
• Exhaust rocker arm
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
EAS23840

CHECKING THE CAMSHAFT

1. Check:
• Bearing
Damage/wear → Replace.
2. Check:
• Camshaft lobes
Blue discoloration/pitting/scratches →
Replace the camshaft.
3. Measure:
• Camshaft lobe dimensions "a" and "b"
Out of specification → Replace the cam-
shaft.
Camshaft lobe dimension limit
Intake "a"
36.890–36.990 mm (1.4524–
1.4563 in)
Limit
36.790 mm (1.4484 in)
Intake "b"
30.111–30.211 mm (1.1855–
1.1894 in)
Limit
30.011 mm (1.1815 in)
Exhaust "a"
36.891–36.991 mm (1.4524–
1.4563 in)
Limit
36.791 mm (1.4485 in)
Exhaust "b"
30.092–30.192 mm (1.1847–
1.1887 in)
Limit
29.992 mm (1.1808 in)
5-7
CAMSHAFT