Yamaha YZF-R25, Service Manual

Page: 231 / 456

CAMSHAFTS
5-14
5. Remove:
• Intake camshaft “1”
• Exhaust camshaft “2”
TIP
To prevent the timing chain from falling into the
crankcase, fasten it with a wire “3”.
6. Remove:
• Camshaft sprocket “1”
TIP
While holding the camshaft sprocket with the ro-
tor holding tool “2”, loosen the camshaft sprock-
et bolts in the proper sequence as shown.
EAS30257
CHECKING THE CAMSHAFTS
1. Check:
• Camshaft lobes
Blue discoloration/pitting/scratches
→
Re-
place the camshaft.
2. Measure:
• Camshaft lobe dimensions “a” and “b”
Out of specification
→
Replace the camshaft.
3. Measure:
• Camshaft runout
Out of specification
→
Replace.
Rotor holding tool
90890-01235
Universal magneto and rotor
holder
YU-01235
2
1
2
1
3
2
1
2
1
Camshaft lobe dimensions
Lobe height (Intake)
32.050–32.150 mm (1.2618–
1.2657 in)
Limit
31.950 mm (1.2579 in)
Base circle diameter (Intake)
24.972–25.072 mm (0.9831–
0.9871 in)
Limit
24.872 mm (0.9792 in)
Lobe height (Exhaust)
31.650–31.750 mm (1.2461–
1.2500 in)
Limit
31.550 mm (1.2421 in)
Base circle diameter (Exhaust)
25.082–25.182 mm (0.9875–
0.9914 in)
Limit
24.982 mm (0.9835 in)