Yamaha 2012 Grizzly 300 Service Manual page 138

VALVES AND VALVE SPRINGS
4. Measure:
• runout (valve stem)
Out of specification
TIP
• When installing a new valve always replace
the guide.
• If the valve is removed or replaced always
replace the oil seal.
5. Eliminate:
• carbon deposits
(from the valve face and valve seat)
6. Check:
• valve seats
Pitting/wear
7. Measure:
• valve seat width
Out of specification
seat.
a. Apply Mechanic's blueing dye (Dykem)
the valve face.
b. Install the valve into the cylinder head.
c. Press the valve through the valve guide and
onto the valve seat to make a clear pattern.
d. Measure the valve seat width. Where the
valve seat and valve face made contact,
blueing will have been removed.
e. If the valve seat is too wide, too narrow, or
the seat is not centered, the valve seat must
be refaced.
4-18
ENG
→
Replace.
Runout limit
0.01 mm (0.0004 in)
→
Reface the valve seat.
a
→
Reface the valve
Valve seat width
Intake
<Limit>: 1.6 mm (0.063 in)
Exhaust
<Limit>: 1.6 mm (0.063 in)
to
b