Yamaha WR45OFR service manual Valve spring

VALVES AND VALVE SPRINGS

ENG

Valve spring

1.Measure:

●Valve spring free length a

Out of specification → Replace.

Free length (valve spring):

Intake:

37.03mm (1.46 in) <Limit>: 35.17 mm (1.38 in)

Exhaust:

37.68mm (1.48 in) <Limit>: 35.79 mm (1.41 in)

2.Measure:

●Compressed spring force a Out of specification → Replace.

bInstalled length

Compressed spring force:

Intake:

111.3~ 127.9 N at 27.87 mm

(11.3 ~ 13.0 kg at 27.87 mm,

24.91~ 28.66 lb at 1.10 in)

Exhaust:

127.4~ 146.4 N at 27.38 mm

(13.0 ~ 14.9 kg at 27.38 mm,

28.66~ 32.85 lb at 1.08 in)

3.Measure:

●Spring tilt a

Out of specification → Replace.

Spring tilt limit: Intake:

2.5˚/1.61 mm (0.063 in) Exhaust:

2.5˚/1.65 mm (0.065 in)

Valve lifter

1.Inspect:

●Valve lifter

Scratches/damage → Replace both lift- ers and cylinder head.

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