Yamaha Wr 450 F Owners Manual

							 
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CHASSIS/BRAKE SYSTEM AIR BLEEDING 
EC360000 
CHASSIS 
EC361012 
BRAKE SYSTEM AIR BLEEDING
WARNING
 
Bleed the brake system if: 
 
The system has been disassembled. 
 
A brake hose has been loosened or
removed. 
 
The brake fluid is very low. 
 
The brake operation is faulty.
A dangerous loss of braking performance
may occur if the brake system is not prop- 
erly bled. 
1. Remove: 
 
Master cylinder cap 
 
Diaphragm 
 
Protector (rear brake)
2. Bleed: 
 
Brake fluid 
Å 
Front 
ı 
Rear 
Air bleeding steps: 
a. Add proper brake fluid to the reservoir.
b. Install the diaphragm. Be careful not to
spill any fluid or allow the reservoir to
overflow.
c. Connect the clear plastic tube  
2 
 tightly
to the caliper bleed screw  
1.
d. Place the other end of the tube into a
container.
e. Slowly apply the brake lever or pedal
several times.
f. Pull the lever in or push down on the
pedal. Hold the lever or pedal in position.
g. Loosen the bleed screw and allow the
lever or pedal to travel towards its limit.
h. Tighten the bleed screw when the lever
or pedal limit has been reached; then
release the lever or pedal.
T R..
Bleed screw:
6 Nm (0.6 m • kg, 4.3 ft • lb)
i. Repeat steps (e) to (h) until of the air
bubbles have been removed from the
system.
Å
ı 
						

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FRONT BRAKE ADJUSTMENT
3. Install:
Protector (rear brake)
Diaphragm
Master cylinder cap
NOTE:
If bleeding is difficult, it may be necessary to
let the brake fluid system stabilize for a few
hours. Repeat the bleeding procedure when
the tiny bubbles in the system have disap-
peared.
j. Add brake fluid to the level line on the
reservoir.
WARNING
Check the operation of the brake after
bleeding the brake system.
EC362040
FRONT BRAKE ADJUSTMENT
1. Check:
Brake lever position a 
Brake lever position a:
Standard position Extent of adjustment
95 mm (3.74 in)76 ~ 97 mm 
(2.99 ~ 3.82 in)
2. Remove:
Lever cover
3. Adjust:
Brake lever position
4. Install:
Lever cover Brake lever position adjustment steps:
Loosen the locknut 1.
Turn the adjusting bolt 2 until the lever
position a is within specified position.
Tighten the locknut.
T R..
Locknut:
5 Nm (0.5 m • kg, 3.6 ft • lb)
CAUTION:
Be sure to tighten the locknut, as it will
cause poor brake performance. 
						

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INSP
ADJREAR BRAKE ADJUSTMENT/
FRONT BRAKE PAD INSPECTION AND REPLACEMENT
EC364002
REAR BRAKE ADJUSTMENT
1. Check:
Brake pedal height a 
Out of specification → Adjust.
Brake pedal height a:
5 mm (0.20 in)
2. Adjust:
Brake pedal height
Pedal height adjustment steps:
Loosen the locknut 1.
Turn the adjusting nut 2 until the pedal
height a is within specified height.
Tighten the locknut.
WARNING
Adjust the pedal height between the
maximum Å and the minimum ı as
shown. (In this adjustment, the bolt 3
end b should protrude out of the
threaded portion 4 but not be less than
2 mm (0.08 in) c away from the brake
pedal 5).
After the pedal height adjustment, make
sure that the rear brake does not drag.
Å
ı
EC365080
FRONT BRAKE PAD INSPECTION AND 
REPLACEMENT
1. Inspect:
Brake pad thickness a 
Out of specification → Replace as a
set.
2. Replace:
Brake pad
Brake pad thickness a:
Standard 
4.4 mm (0.17 in) 1.0 mm (0.04 in)
Brake pad replacement steps:
Remove the pad pin plug 1. 
						

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FRONT BRAKE PAD INSPECTION AND REPLACEMENT
Loosen the pad pin 2.
Remove the brake hose holder 3 and cal-
iper 4 from the front fork.
Remove the pad pin and brake pads 5.
Connect the transparent hose 6 to the
bleed screw 7 and place the suitable con-
tainer under its end.
Loosen the bleed screw and push the cali-
per piston in.
CAUTION:
Do not reuse the drained brake fluid.
Tighten the bleed screw.
T R..
Bleed screw:
6 Nm (0.6 m • kg, 4.3 ft • lb)
Install the brake pads 8 and pad pin.
NOTE:
Install the brake pads with their projec-
tions a into the caliper recesses b.
Temporarily tighten the pad pin at this
point.
Install the brake hose holder 9 and cali-
per 0 and tighten the pad pin A.
NOTE:
Fit the brake hose holder cut c over the
projection d on the front fork and clamp the
brake hose.
T R..
Bolt (caliper):
23 Nm (2.3 m • kg, 17 ft • lb)
Pad pin:
18 Nm (1.8 m • kg, 13 ft • lb) 
						

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REAR BRAKE PAD INSPECTION AND REPLACEMENT
3. Inspect:
Brake fluid level
Refer to “BRAKE FLUID LEVEL
INSPECTION” section.
4. Check:
Brake lever operation
A softy or spongy feeling → Bleed
brake system.
Refer to “BRAKE SYSTEM AIR
BLEEDING” section.
Install the pad pin plug B.
T R..
Pad pin plug:
3 Nm (0.3 m • kg, 2.2 ft • lb)
EC366060
REAR BRAKE PAD INSPECTION AND 
REPLACEMENT
1. Inspect:
Brake pad thickness a 
Out of specification → Replace as a
set.
2. Replace:
Brake pad
Brake pad thickness a:
Standard 
6.4 mm (0.25 in) 1.0 mm (0.04 in)
Brake pad replacement steps:
Remove the protector 1 and pad pin plug
2.
Loosen the pad pin 3.
Remove the rear wheel 4 and caliper 5.
Refer to “FRONT WHEEL AND REAR
WHEEL” section in the CHAPTER 5. 
						

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REAR BRAKE PAD INSPECTION AND REPLACEMENT
Remove the pad pin 6 and brake pads 7.
Connect the transparent hose 8 to the
bleed screw 9 and place the suitable con-
tainer under its end.
Loosen the bleed screw and push the cali-
per piston in.
CAUTION:
Do not reuse the drained brake fluid.
Tighten the bleed screw.
T R..
Bleed screw:
6 Nm (0.6 m • kg, 4.3 ft • lb)
Install the brake pad 0 and pad pin A.
NOTE:
Install the brake pads with their projec-
tions a into the caliper recesses b.
Temporarily tighten the pad pin at this
point.
Install the caliper B and rear wheel C.
Refer to “FRONT WHEEL AND REAR
WHEEL” section in the CHAPTER 5.
Tighten the pad pin D.
T R..
Pad pin:
18 Nm (1.8 m • kg, 13 ft • lb)
Install the pad pin plug E and protector F.
T R..
Pad pin plug:
3 Nm (0.3 m • kg, 2.2 ft • lb)
Bolt (protector):
7 Nm (0.7 m • kg, 5.1 ft • lb) 
						

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INSP
ADJREAR BRAKE PAD INSULATOR INSPECTION/
BRAKE FLUID LEVEL INSPECTION
3. Inspect:
Brake fluid level
Refer to “BRAKE FLUID LEVEL
INSPECTION” section.
4. Check:
Brake pedal operation
A softy or spongy feeling → Bleed
brake system.
Refer to “BRAKE SYSTEM AIR
BLEEDING” section.
EC36b000
REAR BRAKE PAD INSULATOR 
INSPECTION
1. Remove:
Brake pad
Refer to “REAR BRAKE PAD INSPEC-
TION AND REPLACEMENT” section.
2. Inspect:
Rear brake pad insulator 1 
Damage → Replace.
EC367001
BRAKE FLUID LEVEL INSPECTION
1. Place the master cylinder so that its top is
in a horizontal position.
2. Inspect:
Brake fluid level
Fluid at lower level → Fill up.
aLower level
ÅFront
ıRear
WARNING
Use only designated quality brake fluid to
avoid poor brake performance.
Refill with same type and brand of brake
fluid; mixing fluids could result in poor
brake performance.
Be sure that water or other contaminants
do not enter master cylinder when refill-
ing.
Clean up spilled fluid immediately to
avoid erosion of painted surfaces or plas-
tic parts.
Recommended brake fluid:
DOT #4
Å
ı 
						

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SPROCKETS INSPECTION/DRIVE CHAIN INSPECTION
EC368000
SPROCKETS INSPECTION
1. Inspect:
Sprocket teeth a 
Excessive wear → Replace.
NOTE:
Replace the drive, driven sprockets and drive
chain as a set.
DRIVE CHAIN INSPECTION
1. Remove:
Drive chain 1 
NOTE:
Remove the drive chain using a chain cutter
2.
2. Clean:
Drive chain
Brush off as much dirt as possible.
Then clean the chain using the chain
cleaner.
CAUTION:
This machine has a drive chain with small
rubber O-rings 1 between the side plates.
Steam cleaning, high-pressure washes,
certain solvent and kerosene can damage
these O-rings.
1
3. Inspect:
O-ring 1 (drive chain)
Damage → Replace the drive chain.
Roller 2 
Side plate 3 
Damage/wear → Replace the drive
chain.
4. Measure:
Drive chain length (10 links) a 
Out of specification → Replace.
Drive chain length (10 links):
: 150.1 mm (5.91 in) 
						

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DRIVE CHAIN INSPECTION
5. Check:
Drive chain stiffness a 
Clean and oil the chain and hold as
illustrated.
Stiff → Replace the drive chain.
6. Install:
Joint 1 
O-ring 2 
Drive chain 3 
NOTE:
When installing the drive chain, apply the lith-
ium soap base grease on the joint and O-rings.
7. Install:
Link plate 4 
NOTE:
Press the link plate onto the joint using a
chain riveter 5.
Rivet the end of the joint using a chain riv-
eter.
After riveting the joint, make sure its move-
ment is smooth.
New
New
8. Lubricate:
Drive chain
Drive chain lubricant:
SAE 10W-30 motor oil or suit-
able chain lubricants 
						

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DRIVE CHAIN SLACK ADJUSTMENT
DRIVE CHAIN SLACK ADJUSTMENT
1. Elevate the rear wheel by placing the
suitable stand under the engine.
2. Check:
Drive chain slack a 
Above the seal guard installation bolt.
Out of specification → Adjust.
NOTE:
Before checking and/or adjusting, rotate the
rear wheel through several revolutions and
check the slack several times to find the tight-
est point. Check and/or adjust the chain slack
with the rear wheel in this “tight chain” position.
Drive chain slack:
40 ~ 50 mm (1.6 ~ 2.0 in)
3. Adjust:
Drive chain slack
Drive chain slack adjustment steps:
Loosen the axle nut 1 and locknuts 2.
Adjust the chain slack by turning the
adjusters 3.
To tighten → Turn the adjuster 3 coun-
terclockwise.
To loosen → Turn the adjuster 3 clock-
wise and push wheel for-
ward.
Turn each adjuster exactly the same
amount to maintain correct axle alignment.
(There are marks a on each side of the
chain puller alignment.)
NOTE:
Turn the adjuster so that the chain is in line
with the sprocket, as viewed from the rear.
CAUTION:
Too small chain slack will overload the
engine and other vital parts; keep the
slack within the specified limits.