Checking The Camshaft; Checking The Camshaft Sprocket; Checking The Decompression System - Yamaha YFM660FP Service Manual

CAMSHAFT AND CYLINDER HEAD
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CHECKING THE CAMSHAFT

1.Check:
Cam lobes
●
Pitting/scratches/blue discoloration →
Replace.
2.Measure:
Cam lobes length a and b.
●
Out of specification → Replace.
Camshaft lobe limit:
Intake:
a 35.59 mm (1.4012 in)
b 29.96 mm (1.1795 in)
Exhaust:
a 36.40 mm (1.4331 in)
b 30.01 mm (1.1815 in)

CHECKING THE CAMSHAFT SPROCKET

1.Check:
Camshaft sprocket
●
Wear/damage → Replace the camshaft
sprocket and timing chain as a set.
a 1/4 of a tooth
b Correct
1 Timing chain
2 Sprocket
CHECKING THE DECOMPRESSION
SYSTEM
1.Check:
Decompression system
●
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Checking steps:
Check while the camshaft sprocket is installed
on the camshaft.
● Check that the decompressor lever pin 1
projects from the camshaft.
● Check that the decompressor cam 2 moves
smoothly.
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ENG