Yamaha WR250F 2022 Owner's Service Manual page 219

2 2
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 generator 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.
TIP
Make sure that the alignment mark "c" on the ex-
haust camshaft sprocket and the alignment
mark "d" on the intake camshaft sprocket are
aligned with the edge of the cylinder head.
1 1
E
M
a a
b
a
5-18
3
d
ECA24620
NOTICE
Do not turn the crankshaft during the cam-
shaft installation. Damage or improper valve
timing will result.
d. Install the clips, the camshaft caps and the
bolts (camshaft cap).
Bolt (camshaft cap)
10 N·m (1.0 kgf·m, 7.4 lb·ft)
TIP
• Before installing the clips, cover the cylinder
head with a clean cloth to prevent the clips
from coming off into the cylinder head cavity.
• Apply the engine oil to the threads and contact
surfaces.
• Tighten the bolts to the specified torque in two
or three steps in the proper tightening se-
quence as shown.
ECA24630
NOTICE
The bolts (camshaft cap) must be tightened
evenly, or damage to the cylinder head, cam-
shaft caps, and camshaft will result.
3 3
1 1 1 2 2
E
2. Install:
• Timing chain tensioner
a. While pressing the tensioner rod lightly
with your fingers, use a thin screwdriver to
wind the tensioner rod up fully clockwise.
CAMSHAFT
c
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6 6 5 5