Checking The Camshaft - Yamaha YZ450F Owner's Service Manual

5. Remove:
• Exhaust camshaft "1"
• Intake camshaft "2"
TIP
Attach a wire "3" to the timing chain to prevent
it from falling into the crankcase.
2
3

CHECKING THE CAMSHAFT

EASB111208
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 cam-
shaft.
Camshaft lobe dimensions
Lobe height (Intake)
37.630–37.730 mm (1.4815–
1.4854 in)
Limit
37.620 mm (1.4811 in)
Base circle diameter (Intake)
27.950–28.050 mm (1.1004–
1.1043 in)
Limit
27.940 mm (1.0000 in)
Lobe height (Exhaust)
33.870–33.970 mm (1.3335–
1.3374 in)
Limit
33.860 mm (1.3331 in)
Base circle diameter (Exhaust)
24.711–24.811 mm (0.9729–
0.9768 in)
Limit
24.701mm (0.9725 in)
1
3. Measure:
• Camshaft runout
Out of specification  Replace.
4. Measure:
• Camshaft-journal-to-camshaft-cap clear-
ance
Out of specification  Measure the cam-
shaft journal diameter.
5-15
CAMSHAFT
Camshaft runout limit
0.030 mm (0.0012 in)
Camshaft-journal-to-camshaft-
cap clearance
0.028–0.062 mm (0.0011–0.0024
in)