Yamaha YZ450FT Owner's Service Manual page 134

CAMSHAFTS
Decompression system
1. Check:
• Decompression system
Checking steps:
• Check that the decompressor cam 1
moves smoothly.
• Check that the decompressor lever pin 2
projects from the camshaft.
Timing chain tensioner
1. Check:
• While pressing the tensioner rod lightly
with fingers, use a thin screwdriver 1
and wind the tensioner rod up fully clock-
wise.
• When releasing the screwdriver by press-
ing lightly with fingers, make sure that the
tensioner rod will come out smoothly.
• If not, replace the tensioner assembly.
ASSEMBLY AND INSTALLATION
1. Install:
• Exhaust camshaft 1
• Intake camshaft 2
Installation steps:
• Turn the crankshaft counterclockwise until
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
camshafts.
• Apply the engine oil on the decompression
system.
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ENG