Yamaha XVS650 Service Manual page 131

VALVES AND VALVE SPRINGS
ENG
5.Measure:
• Runout (valve stem)
Out of specification
-7
Replace.
Runout limit:
0.03 mm (0.001 in)
/1
302·(1004
®
1..- ...
4 - 24
NOTE: _
• When installing a new valve always
replace the guide.
• If the valve is removed or replaced always
replace the oil seal.
6.Eliminate:
• Carbon deposits
(from the
valve
face and
valve
seat)
7.lnspect:
• Valve seats
Pitting/wear
-7
Reface the valve seat.
8.Measure:
• Valve seat width
®
Out of specification
-7
Reface the valve
seat.
Valve seat width:
Intake:
1.0 - 1.2 mm (0.039 - 0.047 in)
<limit>: 1.8 mm (0.071 in)
Exhaust:
1.0 - 1.2 mm (0.039 - 0.047 in)
<limit>: 1.8 mm (0.071 in)
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Measurement steps:
.Apply Mechanic's blueing dye (Dykem) <£)
to the valve face.
• Install the valve into the cylinder head.
• Press the valve through the valve guide
and onto the valve seat to make a clear
pattern.
• Measure the
valve
seat width. Where the
valve seat and varve face made contact,
blueing will have been removed .
• If the valve seat is too wide, too narrow,
or the seat is not centered, the valve seat
must be refaced.
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