Yamaha YZ250F(R) Owner's Service Manual page 130

CAMSHAFTS
Decompression system
1. Check:
Decompression system
●
Checking steps:
Check that the decompression mecha-
●
nism cam 1 moves smoothly.
Check that the decompression mechanism
●
cam 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
clockwise.
When releasing the screwdriver by
●
pressing lightly with fingers, make sure
that the tensioner rod will come out
smoothly.
If not, replace the tensioner assembly.
●
ASSEMBLY AND INSTALLATION
Camshaft
1. Install:
Exhaust camshaft 1
●
Intake camshaft 2
●
Installation steps:
Turn the crankshaft counterclockwise with
●
a wrench.
NOTE:
Apply the molybdenum disulfide oil on the
●
camshafts.
Apply the engine oil on the decompression
●
system.
Squeezing the
●
allows the crankshaft to be turned easily.
Align the T.D.C. mark a on the rotor with the
●
align mark b on the crankcase cover when
piston is at T.D.C. on compression stroke.
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ENG
decompression lever