Checking The Valve Seats - Yamaha XT660R 2004 Service Manual

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VALVES AND VALVE SPRINGS
6. Measure:
• valve stem runout
NOTE:
_
• When installing a new valve, always replace
the valve guide.
• If the valve is removed or replaced, always
replace the valve stem seal.
EAS00240

CHECKING THE VALVE SEATS

The following procedure applies to all of the
valves and valve seats.
1. Eliminate:
• carbon deposits
2. Check:
• valve seat
3. Measure:
• valve seat width a
M MMM
a. Apply Mechanic's blueing dye (Dykem) onto
b. Install the valve into the cylinder head.
c. Press the valve through the valve guide and
d. Measure the valve seat width.
NOTE:
_
Where the valve seat and valve face contacted
one another, the blueing will have been
removed.
L LLL
5 - 27
Out of specification → Replace the valve.
Valve stem runout
0.010 mm (0.0004 in)
(from the valve face and valve seat)
Pitting/wear → Replace the cylinder head.
Out of specification → Replace the cylinder
head.
Valve seat width
Intake
1.00 ~ 1.20 mm
(0.0394 ~ 0.0472 in)
Exhaust
1.00 ~ 1.20 mm
(0.0394 ~ 0.0472 in)
M MMM M M MMM M M MMM M
the valve face.
onto the valve seat to make a clear impres-
sion.
L LLL L L LLL L L LLL L
ENG
M MMM M M MMM M MMM
L LLL L L LLL L LLL