Yamaha RX10K Supplementary Service Manual page 293

VALVES AND VALVE SPRINGS
6. Measure:
S Valve stem runout
Out of specification ! Replace the valve.
NOTE:
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.
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.
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.
NOTE:
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
NOTE:
After replacing the cylinder head or replacing
the valve and valve guide, the valve seat and
valve face should be lapped.
5-26
ENG
Valve stem runout:
0.01 mm (0.0004 in)
Valve seat width:
0.9 X 1.1 mm
Intake:
(0.035 X 0.043 in)
Exhaust: 0.9 X 1.1 mm
(0.035 X 0.043 in)