Valve Seat Inspection; Valve Face Contact Width - Yamaha EF2000iS Service Manual

b
a

VALVE SEAT INSPECTION

1. Remove carbon deposits from the valve
face and valve seat.
a
2. Apply a small amount of coarse mechan-
ic's blueing dye (Dykem) to the valve face
a.
3. Insert the valve into the valve guide and
use a valve lapper to contact the valve
face with the valve seat.
TIP
Do not rotate the valve while the valve face is
contacting the valve seat.
4. Measure:
9 Valve face contact width b
Make sure that the contact width along
the entire valve face is within specifica-
tions.
Out of specification/rough/eccentric
wear → Replace.
5. Measure:
9 Valve seat contact width a
Make sure that the contact width along
the entire valve seat is within specifica-
tions.
Out of specification/rough/eccentric
wear → Replace.
3-27
ENG
VALVE
Valve face contact width (intake
and exhaust):
0.6 – 0.8 mm
(0.0236 – 0.0315 in)
Limit: 1.6 mm (0.06 in)
Valve seat contact width (intake
and exhaust):
0.6 – 0.8 mm
(0.0236 – 0.0315 in)
Limit: 1.6 mm (0.06 in)