Yamaha XVS650 - 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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