fork YAMAHA WR 450F 2006 Owner's Guide

5 - 30
CHAS
EC554200
Base valve
1. Inspect:
Valve assembly 1
Wear/damage → Replace.
O-ring 2
Damage → Replace.
2
1
EC554400
Fork spring
1. Measure:
Fork spring free length a
Out of specification → Replace.
EC554502
Inner tube
1. Inspect:
Inner tube surface a
Score marks → Repair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock piece → Replace.
Inner tube bends
Out of specification → Replace.
Use the dial gauge 1.
NOTE:
The bending value is shown by one half of the
dial gauge reading.
WARNING
Do not attempt to straighten a bent inner
tube as this may dangerously weaken the
tube.
EC554600
Outer tube
1. Inspect:
Outer tube 1
Score marks/wear/damage → Replace.
Fork spring free length:
Standard Limit
460 mm (18.1 in) 455 mm (17.9 in)
Inner tube bending limit:
0.2 mm (0.008 in)
FRONT FORK

5 - 31
CHAS
EC554700
Cap bolt
1. Inspect:
Cap bolt 1
O-ring 2
Air bleed screw 3
Wear/damage → Replace.
FRONT FORK
EC555000
ASSEMBLY AND INSTALLATION
Front fork assembly
1. Wash the all parts in a clean solvent.
2. Install:
Damper rod 1
To inner tube 2.
CAUTION:
To install the damper rod into the inner
tube, hold the inner tube aslant. If the inner
tube is held vertically, the damper rod may
fall into it, damaging the valve inside.
3. Install:
Copper washer 1
O-ring 2
Base valve 3
To inner tube 4.
4. Tighten:
Base valve 1
NOTE:
Use a damper rod holder 2 to lock the
damper rod 3.
Apply the LOCTITE
® on the base valve
thread.
Damper rod holder:
YM-01494/90890-01494
New
T R..55 Nm (5.5 m · kg, 40 ft · lb)

5 - 32
CHASFRONT FORK
5. Install:
Spring guide 1
Locknut 2
To damper rod 3.
NOTE:
Install the spring guide with its smaller dia.
end a facing downward.
With its thread b facing upward, fully finger
tighten the locknut onto the damper rod.
6. Install:
Dust seal 1
Stopper ring 2
Oil seal 3
Oil seal washer 4
Slide metal 5
To inner tube 6.
NOTE:
Apply the fork oil on the inner tube.
When installing the oil seal, use vinyl seat a
with fork oil applied to protect the oil seal lip.
Install the oil seal with its manufacture’s
marks or number facing the axle holder side.
Install the oil seal washer with its projections
b facing upward.
New
New
7. Install:
Piston metal 1
NOTE:
Install the piston metal onto the slot on inner
tube.
New
8. Install:
Outer tube 1
To inner tube 2.

5 - 33
CHASFRONT FORK
9. Install:
Slide metal 1
Oil seal washer 2
To outer tube slot.
NOTE:
Press the slide metal into the outer tube with
fork seal driver 3.
Fork seal driver:
YM-A0948/90890-01502
10. Install:
Oil seal 1
NOTE:
Press the oil seal into the outer tube with fork
seal driver 2.
Fork seal driver:
YM-A0948/90890-01502
11. Install:
Stopper ring 1
NOTE:
Fit the stopper ring correctly in the groove in
the outer tube.
12. Install:
Dust seal 1
NOTE:
Apply the lithium soap base grease on the
inner tube.

5 - 34
CHASFRONT FORK
13. Check:
Inner tube smooth movement
Tightness/binding/rough spots → Repeat
the steps 2 to 12.
14. Compress the front fork fully.
15. Fill:
Front fork oil
Until outer tube top surface with recom-
mended fork oil 1.
CAUTION:
Be sure to use recommended fork oil. If
other oils are used, they may have an
excessively adverse effect on the front
fork performance.
Never allow foreign materials to enter the
front fork.
Recommended oil:
Suspension oil “S1”
16. After filling, pump the damper rod 1 slowly
up and down more than 10 times to distrib-
ute the fork oil.
17. Fill:
Front fork oil
Until outer tube top surface with recom-
mended fork oil once more.
18. After filling, pump the outer tube 1 slowly
up and down (about 200 mm (7.9 in)
stroke) to distribute the fork oil once more.
NOTE:
Be careful not to excessive full stroke. A stroke
of 200 mm (7.9 in) or more will cause air to
enter. In this case, repeat the steps 15 to 18.

5 - 35
CHASFRONT FORK
19. Wait ten minutes until the air bubbles have
been removed from the front fork, and the
oil has dispense evenly in system before
setting recommended oil level.
NOTE:
Fill with the fork oil up to the top end of the
outer tube, or the fork oil will not spread over to
every part of the front forks, thus making it
impossible to obtain the correct level.
Be sure to fill with the fork oil up to the top of
the outer tube and bleed the front forks.
20. Measure:
Oil level (left and right) a
Out of specification → Adjust.
* For EUROPE
** For AUS, NZ and ZA
NOTE:
Be sure to install the spring guide 2 when
checking the oil level.
WARNING
Never fail to make the oil level adjustment
between the maximum and minimum level
and always adjust each front fork to the
same setting. Uneven adjustment can
cause poor handling and loss of stability.
Standard oil level:
130 mm (5.12 in)
* 127 mm (5.00 in)
** 125 mm (4.92 in)
Extent of adjustment:
95 ~ 150 mm (3.74 ~ 5.91 in)
From top of outer tube with
inner tube and damper rod
1
fully compressed without
spring.

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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..23 Nm (2.3 m · kg, 17 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)

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CHASFRONT FORK
5. Install:
Speed sensor lead 1
Plate 1 2
Bolt (plate 1) 3
To protector (right) 4.
NOTE:
Install the speed sensor lead so that its paint
a directs as shown and align the bottom b of
the plate 1 with the same paint.
a
b
4 31
2
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
6. Install:
Speed sensor lead 1
Plate 2 2
Screw (plate 2) 3
To protector (right) 4.
NOTE:
Install the plate 2 in the direction as shown.
1
22
1
3
4
T R..0.5 Nm (0.05 m · kg, 0.36 ft · lb)
7. Install:
Protector 1
Bolt (protector) 2
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
8. Adjust:
Rebound damping force
NOTE:
Turn in the damping adjuster 1 finger-tight
and then turn out to the originally set position.

5 - 46
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 nodanger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Headlight
Handlebar Refer to “HANDLEBAR” section.
Hose guide
Front fender
1 Multi-function meter 1
2 Multi-function meter bracket 1
3 Main switch 1 Disconnect the main switch lead.
4 Steering shaft cap 1
5 Steering shaft nut 1
6 Front fork 2 Refer to “FRONT FORK” section.
7 Handle crown 1
8 Ring nut 1 Use special tool.
Refer to “REMOVAL POINTS”.
9 Under bracket 1
10 Bearing race cover 1
21
STEERING