Yamaha WR450F(R) Owner's Service Manual page 149

CAMSHAFTS
Decompression system
1. Check:
Decompression system
G
Checking steps:
Check that the decompressor cam 1
G
moves smoothly.
Check that the decompressor lever pin 2
G
projects from the camshaft.
Timing chain tensioner
1. Check:
While pressing the tensioner rod lightly
G
with fingers, use a thin screwdriver 1
and wind the tensioner rod up fully
clockwise.
When releasing the screwdriver by
G
pressing lightly with fingers, make sure
that the tensioner rod will come out
smoothly.
If not, replace the tensioner assembly.
G
ASSEMBLY AND INSTALLATION
1. Install:
Exhaust camshaft 1
G
Intake camshaft 2
G
Installation steps:
Turn the crankshaft counterclockwise until
G
the "I" mark a on the rotor is aligned with
the stationary pointer b on the crankcase
cover.
NOTE:
Apply the molybdenum disulfide oil on the
G
camshafts.
Apply the engine oil on the decompression
G
system.
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ENG