Yamaha XVS6501997 Service Manual page 128

VALVES AND VALVE SPRINGS
b
5. Measure:
S Runout (valve stem)
Out of specification ! Replace.
Runout limit:
0.03 mm
NOTE:
D When installing a new valve always replace
the guide.
D If the valve is removed or replaced always re-
place the oil seal.
6. Eliminate:
S Carbon deposits
(from the valve face and valve seat)
7. Inspect:
S Valve seats
Pitting/wear ! Reface the valve seat.
8. Measure:
S Valve seat width a
Out of specification ! Reface the valve
seat.
Valve seat width:
Intake:
Exhaust:
*****************************************************
Measurement steps:
D Apply Mechanic's blueing dye (Dykem) b to
the valve face.
D Install the valve into the cylinder head.
D 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.
D If the valve seat is too wide, too narrow, or the
seat is not centered, the valve seat must be
refaced.
*****************************************************
4-24
ENG
1.0 X 1.2 mm
<Limit>: 1.8 mm
1.0 X 1.2 mm
<Limit>: 1.8 mm