Yamaha RX10K, Supplementary Service Manual

Page: 293 / 523

5-26
VALVES AND VALVE SPRINGS
ENG
NOTE:
NOTE:
NOTE:
6. Measure:
S
Valve stem runout
Out of specification
!
Replace the valve.
S
When installing a new valve, always replace
the valve guide.
S
If the valve is removed or replaced, always re-
place the oil seal.
Valve stem runout:
0.01 mm (0.0004 in)
7. Eliminate:
S
Carbon deposits
(from the valve face and valve seat)
8. Inspect:
S
Valve seat
Pitting/ wear
!
Replace the cylinder head.
9. Measure:
S
Valve seat width
a
Out of specification
!
Replace the cylinder
head.
Valve seat width:
Intake: 0.9
X
1.1 mm
(0.035
X
0.043 in)
Exhaust: 0.9
X
1.1 mm
(0.035
X
0.043 in)
Measurement steps:
S
Apply Mechanic’s blueing dye (Dykem) 1
onto the valve face.
S
Install the valve into the cylinder head.
S
Press the valve through the valve guide and
onto the valve seat to make a clear pattern.
S
Measure the valve seat width.
Where the valve seat and valve face contacted
one another, the blueing will have been re-
moved.
10. Lap:
S
Valve face
S
Valve seat
After replacing the cylinder head or replacing
the valve and valve guide, the valve seat and
valve face should be lapped.