Yamaha WR250F Owner's Service Manual page 111

The camshafts should be installed
onto the cylinder head so that the
punch mark "c" on the exhaust cam-
shaft and the punch mark "d" on the
intake camshaft must align with the
cylinder head surface, as shown in
the illustration.
Do not turn the crankshaft during
the camshaft installation. Damage
or improper valve timing will re-
sult.
d. Install the clips, camshaft caps "4"
and bolts (camshaft cap) "5".
Bolt (camshaft cap):
10 Nm (1.0 m•kg, 7.2
ft•lb)
• Before removing the clips, cover the
cylinder head with a clean rag to
prevent the clips from into the cylin-
der head cavity.
• Apply the molybdenum disulfide oil
on the thread of the bolts (camshaft
cap).
• Tighten the bolts to the specified
torque in two or three steps in the
proper tightening sequence as
shown.
The bolts (camshaft cap) must be
tightened evenly, or damage to the
cylinder head, camshaft caps, and
camshaft will result.
2. Install:
• Timing chain tensioner
Installation steps:
a. While pressing the tensioner rod
lightly with fingers, use a thin
screwdriver and wind the tension-
er rod up fully clockwise.
b. With the rod fully wound and the
chain tensioner UP mark "a" fac-
ing upward, install the gasket "1"
and the timing chain tensioner "2",
and tighten the bolt "3" to the
specified torque.
Bolt (timing chain ten-
sioner):
10 Nm (1.0 m•kg, 7.2
ft•lb)
c. Release the screwdriver, check
the tensioner rod to come out and
tighten the gasket "4" and the cap
bolt "5" to the specified torque.
Tensioner cap bolt:
7 Nm (0.7 m•kg, 5.1
ft•lb)
3. Turn:
• Crankshaft
Counterclockwise several turns.
4. Check:
• Rotor T.D.C. mark
Align with the crankcase align
mark.
• Camshaft match marks
Align with the cylinder head sur-
face.
→
Out of alignment Adjust.
5. Install:
5-17
CAMSHAFTS
• Timing mark accessing screw "1"
• Crankshaft end accessing screw
"2"
6. Install:
• Timing chain guide (top side) "1"
• Cylinder head cover gasket "2"
• Cylinder head cover "3"
• Bolt (cylinder head cover) "4"
Bolt (cylinder head cov-
er):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Apply the sealant on the cylinder
head cover gasket.
YAMAHA Bond No. 1215
®
(ThreeBond No. 1215):
90890-85505
7. Install:
• Cylinder head breather hose
• Spark plug
Spark plug:
13 Nm (1.3 m•kg, 9.4
ft•lb)