Replacing The Valve Guides; Checking The Valve Seat - Yamaha F100C Service Manual

Replacing the valve guides

1. Remove the valve guide 1 by striking
the special service tool from the combus-
tion chamber side.
Valve guide remover/installer:
90890-04064
2. Install the new valve guide 2 by striking
the special tool from the camshaft side to
the specified position a.
NOTE:
• Before installing the valve guide, mark its
installation position b as shown.
• Apply engine oil to the surface of the new
valve guide.
Valve guide position a:
11.5 mm (0.45 in)
Valve guide remover/installer:
90890-04064
3. Insert the special service tool into the
valve guide 2, and then ream the valve
guide.
60C5D11
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: 90890-04066
4. Measure the valve guide inside diameter.
Replace the valve guide if out of specifi-
cation.
Valve guide inside diameter:
6.01–6.02 mm (0.2367–0.2370 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.
Cylinder head
S60C5500
5-28
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