Inspection - Yamaha RS90GTZ Service Manual

VALVES AND VALVE SPRINGS
3. Remove:
• Valve cotters
TIP
Remove the valve cotters by compressing the
valve spring with the valve spring compressor
and valve spring compressor adapter 19.5
mm (valve spring compressor attachment)
4. Remove:
• Upper spring seat
• Valve spring
• Valve
• Valve stem seal
• Lower spring seat
TIP
Identify the position of each part very carefully
so that it can be reinstalled in its original place.

INSPECTION

1. Measure:
• Valve-stem-to-valve-guide clearance
Out of specification → Replace the valve
guide.
Valve-stem-to-valve-guide clearance =
Valve guide inside diameter
Valve stem diameter
5-34
ENG
Valve spring compressor:
YM-04019, 90890-04019
Valve spring compressor adapter
19.5 mm:
YM-04114
Valve spring compressor
attachment:
90890-04114
Valve-stem-to-valve-guide
clearance:
Intake:
0.010 ~ 0.037 mm
(0.0004 ~ 0.0015 in)
<Limit>: 0.080 mm (0.0031 in)
Exhaust:
0.025 ~ 0.052 mm
(0.0010 ~ 0.0020 in)
<Limit>: 0.100 mm (0.0039 in)
.
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