Yamaha F75F - Refacing the Valve Seat

Camshaft and valve
7-35
a. Remove carbon deposits from the
valve.
b. Apply a thin, even layer of blue layout
fluid (Dykem) onto the valve seat.
c. Push the valve lightly against the valve
seat using the special service tool “1”.
d. Measure the valve seat contact width
“a”
where the blue layout fluid is ad-
hered to the valve face.
Refacing the valve seat
After every lapping procedure, make sure
to clean off any remaining lapping com
-
pound from the cylinder head and valves.
1. Reface:
• Valve seat
Seat contact width IN
1.10–1.50 mm (0.0433–0.0591
in)
Limit
1.950 mm (0.0768 in)
Seat contact width EX
1.10–1.50 mm (0.0433–0.0591
in)
Limit
1.950 mm (0.0768 in)
Valve lapper “1”
90890-04101
1
A. Worldwide
B. USA and Canada
Valve seat cutter holder
90890-06316
Intake:
Valve seat cutter 30
90890-06326
Valve seat cutter 45
90890-06325
Valve seat cutter 60
90890-06324
Exhaust:
Valve seat cutter 30
90890-06328
Valve seat cutter 45
90890-06312
Valve seat cutter 60
90890-06315
604530
A
45
45
30
30
60
B