Yamaha WaveRunner FX140 Manuel D'entretien page 364

POWR
VALVES AND VALVE SPRINGS
Valve seat inspection
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 obtainable)
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.
Valve seat contact width a:
0.9–1.1 mm (0.0354–0.0433 in)
5-72
E