Yamaha WR250F Manuel D'atelier page 344

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VALVES AND VALVE SPRINGS
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Valve spring
1. Measure:
Valve spring free length a
Out of specification → Replace.
Free length (valve spring):
Intake:
37.81 mm (1.49 in)
<Limit>: 35.9 mm (1.41 in)
Exhaust:
37.54 mm (1.48 in)
<Limit>: 35.7 mm (1.41 in)
2. Measure:
Compressed spring force a
Out of specification → Replace.
b Installed length
Compressed spring force:
Intake:
10.1 ~ 11.6 kg at 29.13 mm
(22.27 ~ 25.57 lb at 1.15 in)
Exhaust:
12.9 ~ 14.7 kg at 29.30 mm
(28.44 ~ 32.41 lb at 1.15 in)
3. Measure:
Spring tilt a
Out of specification → Replace.
Spring tilt limit:
Intake:
2.5˚/1.7 mm (0.067 in)
Exhaust:
2.5˚/1.6 mm (0.063 in)
Valve lifter
1. Inspect:
Valve lifter
Scratches/damage → Replace both lift-
ers and cylinder head.
ENG