Checking The Decompression System; Installing The Camshafts - Yamaha YZ450F Owner's Service Manual

c. If not, replace the tensioner assembly.
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CHECKING THE DECOMPRESSION SYS-
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TEM
1. Check:
• Decompression system
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a. Check that the decompressor cam "1"
moves smoothly.
b. Check that the decompressor lever pin "2"
projects from the camshaft.
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INSTALLING THE CAMSHAFTS

1. Install:
• Exhaust camshaft "1"
• Intake camshaft "2"
2
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a. Turn the crankshaft counterclockwise with a
wrench.
TIP
• Apply molybdenum disulfide oil to the cam-
shafts.
• Apply the engine oil on the decompression
system.
• Fill the cylinder head with engine oil up to the
tops "a" of the valve lifters.
a
b. Align the top dead center (TDC) mark "a" on
the rotor with the alignment mark "b" on the
crankcase cover.
c. Fit the timing chain "3" onto both camshaft
sprockets and install the camshafts on the
cylinder head.
5-17
CAMSHAFT
1
a
a
b
a