steering YAMAHA YZ450F 2006 User Guide

3 - 43
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 number plate 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.
Install the handlebar so that the projection
c of the handlebar holder (upper) is posi-
tioned at the mark on the handlebar as
shown.
Insert the end of fuel breather hose B into
the hole in the steering shaft.
CAUTION:
First tighten the bolts on the front side of
the handlebar holder (upper), and then
tighten the bolts on the rear side.

3 - 44
INSP
ADJ
T R..
Steering shaft nut:
145 Nm (14.5 m  kg, 105 ft  lb)
Handlebar holder (upper):
28 Nm (2.8 m  kg, 20 ft  lb)
Pinch bolt (handle crown):
23 Nm (2.3 m  kg, 17 ft  lb)
Number plate:
7 Nm (0.7 m  kg, 5.1 ft  lb)
STEERING HEAD INSPECTION AND ADJUSTMENT

5 - 49
CHAS
EC560000
STEERING
Extent of removal:
1 Under bracket removal
2 Bearing removal
Extent of removal Order Part name Q’ty Remarks
STEERING REMOVAL
WARNING
Support the machine securely so there is no
danger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Number plate Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
Handlebar Refer to “HANDLEBAR” section.
Front fender
1 Steering shaft nut 1
2 Front fork 2 Refer to “FRONT FORK” section.
3 Handle crown 1
4 Ring nut 1 Use special tool.
Refer to “REMOVAL POINTS”.
5 Under bracket 1
6 Bearing race cover 1
7 Bearing (upper) 1
8 Bearing (lower) 1
Refer to “REMOVAL POINTS”.
9 Bearing race 2
2
1
STEERING

5 - 50
CHAS
EC563000
REMOVAL POINTS
EC563202
Ring nut
1. Remove:
•Ring nut 1
Use the ring nut wrench 2.
WARNING
Support the steering shaft so that it may
not fall down.
Ring nut wrench:
YU-33975/90890-01403
EC563300
Bearing (lower)
1. Remove:
•Bearing (lower) 1
Use the floor chisel 2.
CAUTION:
Take care not to damage the steering shaft
thread.
Bearing race
1. Remove:
•Bearing race 1
Remove the bearing race using long rod
2 and the hammer.
EC564000
INSPECTION
EC564200
Steering shaft
1. Inspect:
•Steering shaft 1
Bend/damage → Replace.
STEERING

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CHASSTEERING
Bearing and bearing race
1. Wash the bearings and bearing races with
a solvent.
2. Inspect:
•Bearing 1
•Bearing race
Pitting/damage → Replace bearings and
bearing races as a set.
Install the bearing in the bearing races.
Spin the bearings by hand. If the bearings
hang up or are not smooth in their opera-
tion in the bearing races, replace bear-
ings and bearing races as a set.
EC565000
ASSEMBLY AND INSTALLATION
Under bracket
1. Install:
•Bearing (lower) 1
NOTE:
Apply the lithium soap base grease on the dust
seal lip and bearing inner circumference.
2. Install:
•Bearing race
•Bearing (upper) 1
•Bearing race cover 2
NOTE:
Apply the lithium soap base grease on the
bearing and bearing race cover lip.
3. Install:
•Under bracket 1
NOTE:
Apply the lithium soap base grease on the
bearing, the portion a and thread of the steer-
ing shaft.

5 - 52
CHAS
4. Install:
•Ring nut 1
Tighten the ring nut using the ring nut
wrench 2.
Refer to “STEERING HEAD INSPEC-
TION AND ADJUSTMENT” section in the
CHAPTER 3.
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
5. 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.
6. Install:
•Plain washer 1
7. Install:
•Front fork 1
•Handle crown 2
NOTE:
•Temporarily tighten the pinch bolts (under
bracket).
•Do not tighten the pinch bolts (handle crown)
yet.
8. Install:
•Plain washer 1
•Steering shaft nut 2
T R..145 Nm (14.5 m · kg, 105 ft · lb)
STEERING

5 - 53
CHASSTEERING
9. After tightening the nut, check the steering
for smooth movement. If not, adjust the
steering by loosening the ring nut little by
little.
10. Adjust:
•Front fork top end a
Front fork top end (standard)
a:
Zero mm (Zero in)
11. 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.
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)