Yamaha MX250 Service Manual page 66

VALVE
1
2
3
4
5
6
7
8
9
10
2.
a
3.
TIP
The value is half of that indicated on the dial indicator
gauge.
4.
a
5.
b
b. Installed length
a
Measure:
• Valve stem diameter "a"
Valve stem diameter (Intake):
5.948–5.963 mm (0.2342–0.2348 in)
Valve stem diameter (Exhaust):
5.940–5.955 mm (0.2339–0.2344 in)
Limit (Intake):
5.918 mm (0.2330 in)
Limit (Exhaust):
5.910 mm (0.2327 in)
Out of specifications  Replace.
Measure:
• Valve stem runout
Valve stem runout limit:
0.01 mm (0.0004 in)
Out of specifications  Replace.
Measure:
• Valve spring free length "a"
Valve spring free length (Intake):
36.2 mm (1.4252 in)
Valve spring free length (Exhaust):
36.2 mm (1.4252 in)
Limit (Intake):
34.39 mm (1.3539 in)
Limit (Exhaust):
34.39 mm (1.3539 in)
Out of specifications  Replace.
Measure:
• Compressed valve spring force "a"
Out of specification  Replace.
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