Checking The Valve Lifters; Checking The Valve Springs; Checking The Valves - Yamaha F80B Service Manual

POWR
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 8:
90890-04019
Valve spring compressor attachment
9:
90890-06320

Checking the valve lifters

1. Check the valve lifters for damage,
scratches, or wear. Replace if necessary.

Checking the valve springs

1. Measure the valve spring free length a.
Replace if below specification.
5-27
Power unit
Valve spring free length a:
53.20 mm (2.0945 in)
2. Measure the valve spring tilt b. Replace
if above specification.
Valve spring tilt limit b:
2.6 mm (0.10 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 out of specification.
Valve margin thickness a:
Intake:
0.80–1.20 mm
(0.0315–0.0472 in)
Exhaust:
1.00–1.40 mm
(0.0394–0.0551 in)
3. Measure the valve stem diameter b.
Replace if out of specification.
6D93G11