torque YAMAHA WR 450F 2007 User Guide

3 - 45
INSP
ADJ
STEERING HEAD INSPECTION AND ADJUSTMENT
Tighten the ring nut 3 using ring nut
wrench 4.
NOTE:
Apply the lithium soap base grease on the
thread of the steering shaft.
Set the torque wrench to the ring nut
wrench so that they form a right angle.
Ring nut wrench:
YU-33975/90890-01403
T R..
Ring nut (initial tightening):
38 Nm (3.8 m  kg, 27 ft  lb)
Loosen the ring nut one turn.
Retighten the ring nut using the ring nut
wrench.
WARNING
Avoid over-tightening.
T R..
Ring nut (final tightening):
7 Nm (0.7 m  kg, 5.1 ft  lb)
Check the steering shaft by turning it lock
to lock. If there is any binding, remove the
steering shaft assembly and inspect the
steering bearings.
Install the plain washer 5, handle crown
6, plain washer 7, steering shaft nut 8,
handlebar 9, handlebar holder (upper) 0
and headlight A.
NOTE:
The handlebar holder (upper) should be
installed with the punched mark a for-
ward.
Install the handlebar so that the marks b
are in place on both sides.

4 - 30
ENGCAMSHAFTS
Fit the timing chain 3 onto both camshaft
sprockets and install the camshafts on the
cylinder head.
NOTE:
The camshafts should be installed onto the
cylinder head so that the exhaust cam
sprocket punch mark c and the intake cam
sprocket punch mark d align with the sur-
face of the cylinder head.
CAUTION:
Do not turn the crankshaft during the
camshaft installation. Damage or
improper valve timing will result.
Install the clips and camshaft caps 4.
T R..
Bolt (camshaft cap):
10 Nm (1.0 m  kg, 7.2 ft  lb)
NOTE:
Apply the molybdenum disulfide oil on the
thread of the bolts (camshaft cap) 5.
Tighten the bolts to the specified torque in
two or three steps in the proper tightening
sequence as shown.
CAUTION:
The bolts (camshaft cap) must be tight-
ened evenly, or damage to the cylinder
head, camshaft caps, and camshaft will
result.
2. Install:
Timing chain tensioner
Installation steps:
While pressing the tensioner rod lightly
with fingers, use a thin screwdriver and
wind the tensioner rod up fully clockwise.

4 - 31
ENG
With the rod fully wound and the chain ten-
sioner UP mark a facing upward, install
the gasket 1, the chain tensioner 2 and
the gasket 3 and tighten the bolt 4 to the
specified torque.
T R..
Bolt (timing chain tensioner):
10 Nm (1.0 m  kg, 7.2 ft  lb)
Release the screwdriver, check the ten-
sioner rod to come out and tighten the
gasket 5 and the cap bolt 6 to the speci-
fied torque.
T R..
Tensioner cap bolt:
7 Nm (0.7 m  kg, 5.1 ft  lb)
6
5New
3. Turn:
Crankshaft
Counterclockwise several turns
4. Check:
Rotor “I” mark
Align with the crankcase stationary
pointer.
Camshaft match marks
Align with the cylinder head surface.
Out of alignment → Adjust.
5. Install:
Timing plug 1
Straight plug 2
CAMSHAFTS

4 - 35
ENGCYLINDER HEAD
ASSEMBLY AND INSTALLATION
1. Install:
Timing chain guide (front) 1
Dowel pin 2
Cylinder head gasket 3
Cylinder head 4
NOTE:
While pulling up the timing chain, install the
timing chain guide (front) and cylinder head.
New
2. Install:
Plain washer 1
Bolt 2
Installation steps:
CAUTION:
Tighten the cylinder head using the rota-
tion angle procedure to obtain uniform
tightening torque.
Wash the threads and contact surfaces of
the bolts, the contact surfaces of the plain
washers, the contact surface of the cylin-
der head, and the threads of the crank-
case.
Apply the molybdenum disulfide grease on
the threads and contact surfaces of the
bolts and on both contact surfaces of the
plain washers.
Install the plain washers and bolts.
Tighten the bolts to the specified torque in
two or three steps in the proper tightening
sequence as shown.
T R..
Bolts (cylinder head):
1st:
30 Nm (3.0 m  kg, 22 ft  lb)

4 - 36
ENG
Remove the bolts.
Again apply the molybdenum disulfide
grease on the threads and contact sur-
faces of the bolts and on both contact sur-
faces of the plain washers.
Retighten the bolts.
NOTE:
Tighten the bolts to the specified torque in
two or three steps in the proper tightening
sequence as shown.
T R..
Bolts (cylinder head):
2nd:
20 Nm (2.0 m  kg, 14 ft  lb)
Put a mark on the corner 1 of the bolt
(cylinder head) and the cylinder head 2
as shown.
NOTE:
Tighten the bolts 90° in each of the two
steps to reach the specified angle of 180° in
the proper tightening sequence as shown.
T R..
Bolts (cylinder head):
Final:
Specified angle 180°
1
2
180˚
3. Install:
Bolt (cylinder head) 1
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
CYLINDER HEAD

4 - 82
ENGAC MAGNETO AND STARTER CLUTCH
AC MAGNETO AND STARTER CLUTCH
Extent of removal:
1 Starter clutch/wheel gear removal
2 Rotor removal
3 Pickup coil/stator removal
Extent of removal Order Part name Q’ty Remarks
AC MAGNETO AND STATOR
REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section.
Disconnect the AC magneto lead.
1 Shift pedal 1
2 Cover (torque limiter) 1
3 Torque limiter 1 Do not disassemble.
4 Crankcase cover (left) 1
5 Gasket 1
6 Dowel pin 2
13

4 - 85
ENGAC MAGNETO AND STARTER CLUTCH
EC4L4200
Woodruff key
1. Inspect:
Woodruff key 1
Damage → Replace.
Starter clutch
1. Check:
Starter clutch
Damage/wear → Replace.
2. Check:
Idle gear
Idle gear shaft
Starter clutch gear
Pitting/burrs/chips/roughness/wear →
Replace the defective parts.
3. Check:
Starter clutch operation
Install the starter clutch drive gear 1 onto
the starter clutch 2 and hold the starter
clutch.
When turning the starter clutch drive gear
counterclockwise É, the starter clutch and
the starter clutch drive gear should
engage. If the starter clutch drive gear and
starter clutch do not engage, the starter
clutch is faulty and must be replaced.
When turning the starter clutch drive gear
clockwise È, it should turn freely.
If the starter clutch drive gear does not
turn freely, the starter clutch is faulty and
must be replaced.
Torque limiter
1. Check:
Torque limiter
Damage/wear → Replace.

4 - 88
ENG
7. Install:
Shaft 1
Bearing 2
Idle gear 2 3
NOTE:
Apply the engine oil on the shaft, bearing and
idle gear inner circumference.
8. Install:
Dowel pin
Gasket [crankcase cover (left)]
Crankcase cover (left) 1
Bolt [crankcase cover (left)]
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
9. Install:
Plain washer
Torque limiter 1
Plain washer
NOTE:
Apply the engine oil to the shaft and plain
washers.1
10. Install:
Cover (idle gear 1) 1
Bolt 2
NOTE:
Install the cover (idle gear 1) with its mark a
facing upward.
11. Connect:
AC magneto lead
Refer to “CABLE ROUTING DIAGRAM”
section in the CHAPTER 2.
12. Install:
Shift pedal 1
Bolt (shift pedal)
NOTE:
When installing the shift pedal onto the shift
shaft, be sure that the center of the shift pedal
is about 5.1 mm (0.2 in) a above the top of the
footrest.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
AC MAGNETO AND STARTER CLUTCH

5 - 36
CHASFRONT FORK
21. Measure:
Distance a
Out of specification → Turn into the lock-
nut.
Distance
a:
18 mm (0.71 in) or more
Between damper rod
1 top and
locknut
2 top.
22. Loosen:
Rebound damping adjuster 1
NOTE:
Loosen the rebound damping adjuster finger
tight.
Record the set position of the adjuster (the
amount of turning out the fully turned in posi-
tion).
23. Install:
Push rod 1
Fork spring 2
NOTE:
Install the fork spring with the damper rod 3
pulled up.
After installing the fork spring, hold the
damper rod end so that it will not go down.
24. Install:
Spring seat 1
Cap bolt 2
NOTE:
Fully finger tighten the cap bolt onto the
damper rod.
25. Tighten:
Cap bolt (locknut) 1
NOTE:
Hold the locknut 2 and tighten the cap bolt
with specified torque.
T R..29 Nm (2.9 m · kg, 21 ft · lb)

5 - 37
CHASFRONT FORK
26. Install:
Cap bolt 1
To outer tube.
NOTE:
Temporarily tighten the cap bolt.
27. Install:
Protector guide 1
NOTE:
Install the protector guide with its wider side a
facing downward.
Installation
1. Install:
Front fork 1
NOTE:
Temporarily tighten the pinch bolts (under
bracket).
Do not tighten the pinch bolts (handle crown)
yet.
2. Tighten:
Cap bolt 1
3. Adjust:
Front fork top end a
4. Tighten:
Pinch bolt (handle crown) 1
Pinch bolt (under bracket) 2
CAUTION:
Tighten the under bracket to specified
torque. If torqued too much, it may cause
the front fork to malfunction.
Front fork top end (standard)
a:
Zero mm (zero in)
T R..30 Nm (3.0 m · kg, 22 ft · lb)
T R..21 Nm (2.1 m · kg, 15 ft · lb)
T R..21 Nm (2.1 m · kg, 15 ft · lb)