Checking The Valve Seats - Yamaha XT660R Service Manual

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

CHECKING THE VALVE SEATS

The following procedure applies to all of the
valves and valve seats.
1. Eliminate:
2. Check:
3. Measure:
M
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
5 - 27
• valve stem runout
Out of specification → Replace the valve.
the valve guide.
replace the valve stem seal.
Valve stem runout
0.010 mm (0.0004 in)
• carbon deposits
(from the valve face and valve seat)
• valve seat
Pitting/wear → Replace the cylinder head.
• valve seat width a
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)
MMM M MMM M M MMM M M MMM
the valve face.
onto the valve seat to make a clear impres-
sion.
LLL L LLL L L LLL L L LLL
ENG
M M MMM M M MMM M
L L LLL L L LLL L
MMM
LLL