Checking The Valves; Checking The Valve Guides - Yamaha F150A Service Manual

POWR
2. Measure the valve spring tilt b. Replace
if out of specification.
Valve spring tilt limit b:
1.5 mm (0.06 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: 0.70 mm (0.0276 in)
Exhaust: 1.00 mm (0.0394 in)
3. Measure the valve stem diameter b.
Replace if out of specification.
5-29
Power unit
Valve stem diameter b:
Intake:
5.477–5.492 mm
(0.2156–0.2162 in)
Exhaust:
5.464–5.479 mm
(0.2151–0.2157 in)
4. Measure the valve stem runout. Replace
if out of specification.
Valve stem runout:
0.01 mm (0.0004 in)

Checking the valve guides

NOTE:
Before checking the valve guide make sure
that the valve stem diameter is within specifi-
cation.
1. Measure the valve guide inside diameter
a.
a
Valve guide inside diameter a:
5.504–5.522 mm
(0.2167–0.2174 in)
S69J5770
63P3F11