Checking The Valve Seat; Refacing The Valve Seat - Yamaha F200C Service Manual

NOTE:
• Turn the valve guide reamer clockwise to
ream the valve guide.
• Do not turn the reamer counterclockwise
when removing the reamer.
Valve guide reamer: YB-06804
4. Measure the valve guide inside diameter.
Replace the valve guide if out of specifi-
cation.
Valve guide inside diameter:
5.51–5.52 mm (0.2169–0.2173 in)

Checking the valve seat

1. Eliminate carbon deposits from the valve
with a scraper.
2. Apply a thin, even layer of Mechanic's
blueing dye (Dykem) onto the valve seat.
3. Lap the valve slowly on the valve seat
with a valve lapper (commercially obtain-
able) as shown.
4. Measure the valve seat contact width a
where the blueing dye is adhered to the
valve face. Reface the valve seat if the
valve is not seated properly or if the valve
seat contact width is out of specification.
Replace the valve guide if the valve seat
contact is uneven.
69J1D11
Valve seat contact width a:
Intake:
1.1–1.4 mm (0.043–0.055 in)
Exhaust:
1.4–1.7 mm (0.055–0.067 in)

Refacing the valve seat

1. Reface the valve seat with the valve seat
cutter.
È
45˚
30˚
30˚
Valve seat cutter set: YB-91044
Cylinder head
60˚
45˚
S69J5845
5-36
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