Checking The Valve Springs; Checking The Valves - Yamaha F50F Service Manual

6. Remove the intake and exhaust valves.
NOTE:
Be sure to keep the valves, springs, and
other parts in the order as they were
removed.
Valve spring compressor 6:
90890-04019
Valve spring compressor
attachment 7:
90890-06320

Checking the valve springs

1. Measure the valve spring free length a.
Replace if below specification.
Valve spring free length a:
39.85 mm (1.5689 in)
6C13G11
2. Measure the valve spring tilt b. Replace
if above specification.
Valve spring tilt limit b:
1.7 mm (0.07 in)

Checking the valves

1. Check the valve face for pitting or wear.
Replace if necessary.
2. Measure the valve margin thickness a.
Replace if below specification.
Valve margin thickness a:
Intake:
0.8–1.2 mm (0.031–0.047 in)
Exhaust:
1.0–1.4 mm (0.039–0.055 in)
Cylinder head
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