Camshaft Assembly And Installation; Timing Chain Tensioner Inspection - Yamaha WR250F(P) Owner's Service Manual

CAMSHAFTS
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
Camshaft
1. Install:
Exhaust camshaft 1
G
Intake camshaft 2
G
Installation steps:
Turn the crankshaft counterclockwise with
G
a wrench.
NOTE:
Squeezing the decompression lever allows
the crankshaft to be turned easily.
Align the T.D.C. mark a on the rotor with
G
the align mark b on the crankcase cover
when piston is at T.D.C. on compression
stroke.
Fit the timing chain 3 onto both camshaft
G
sprockets and install the camshafts on the
cylinder head.
NOTE:
The camshafts should be installed onto the
cylinder head so that the punch mark c on
the exhaust camshaft and the punch mark
d on the intake camshaft must align with
the cylinder head surface, as shown in the
illustration.
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ENG