2015 YAMAHA YZ450F oil

REAR WHEEL
4-9
TIP
Tighten the self-locking nuts in stages and in a
crisscross pattern.
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EAS1SL5134ASSEMBLING THE REAR WHEEL
1. Install:
• Bearing (right side) “1”
• Circlip “2”
• Spacer “3”
• Bearing (left side) “4”
• Oil seals “5”
TIP
• Apply the lithium soap base grease to the
bearing and the oil seal lip when installing.
• Install the bearing with seal facing outward.
• Right side of bearing shall be installed first.
• Install the oil seal with its manufacture’s
marks or numbers facing outward.
ECA1DX1006
NOTICE
Install the bearing by pressing its outer race
parallel.
TIP
Use a socket “1” that matches the diameter of
the bearing outer race and that of the oil seal.2. Install:
• Brake disc “1”
• Brake disc bolt “2”
TIP
Tighten the bolts in stages and in a crisscross
pattern.
3. Install:
• Collar “1”
TIP
Apply the lithium soap base grease on the oil
seal lip.
EAS1SL5135INSTALLING THE REAR WHEEL
1. Install:
• Rear wheel
New
New
5
43 1
25
LSLS
Brake disc bolt
14 Nm (1.4 m·kgf, 10 ft·lbf)
LOCTITE®
1
T R..
1
LS

FRONT BRAKE
4-18
WARNING
• Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
brake performance.
• Refill with the same type of brake fluid that
is already in the system. Mixing brake flu-
ids may result in a harmful chemical reac-
tion, leading to poor brake performance.
• When refilling, be careful that water does
not enter the brake fluid reservoir. Water
will significantly lower the boiling point of
the brake fluid and could cause vapor
lock.
ECA13540
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
5. Bleed:
• Brake system
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21.
6. Check:
• Brake fluid level
The minimum level mark or below  Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-26.
7. Check:
• Brake lever free play
Refer to “ADJUSTING THE FRONT
BRAKE” on page 3-22.
• Brake lever operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21.
EAS1SL5145REMOVING THE FRONT BRAKE MASTER
CYLINDER
TIP
Before removing the front brake master cylin-
der, drain the brake fluid from the entire brake
system.
1. Remove:
• Union bolt
• Copper washers
• Brake hoses
TIP
To drain any remaining brake fluid, place a con-
tainer under the master cylinder and the end of
the brake hose.
EAS1SL5146CHECKING THE FRONT BRAKE MASTER
CYLINDER
1. Check:
• Brake master cylinder “1”
Damage/scratches/wear  Replace.
• Brake fluid delivery passages “2”
(brake master cylinder body)
Obstruction  Blow out with compressed
air.
2. Check:
• Brake master cylinder kit
Damage/scratches/wear  Replace.
3. Check:
• Brake master cylinder reservoir cap
4. Check:
• Brake hoses
Cracks/damage/wear  Replace.
EAS1SL5147ASSEMBLING THE FRONT BRAKE MAS-
TER CYLINDER
EWA13520
WARNING
• Before installation, all internal brake com-
ponents should be cleaned and lubricated
with clean or new brake fluid.
• Never use solvents on internal brake com-
ponents.
1. Wash the brake master cylinder and the
brake master cylinder kit with brake fluid.
2. Install:
• Primary cylinder cup “1”
• Secondary cylinder cup “2”
Install to the brake master cylinder piston
“3”.
EWA13520
Recommended brake fluid
DOT 4
1
2

FRONT BRAKE
4-20
WARNING
Proper brake hose routing is essential to in-
sure safe vehicle operation.
ECA1DX1007
NOTICE
During installation, bring the brake hose
into contact with the brake master cylinder
projection “a” and make its bent portion “b”
face downward.
TIP
Turn the handlebar toward right and left to
make sure that the brake hose does not touch
other parts (e.g., wire harness, cables, leads).
Adjust if necessary.
3. Pour brake fluid to the brake master cylinder
reservoir up to the specified level.
EWA13540
WARNING
• Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
brake performance.
• Refill with the same type of brake fluid that
is already in the system. Mixing brake flu-
ids may result in a harmful chemical reac-
tion, leading to poor brake performance.
• When refilling, be careful that water does
not enter the brake master cylinder reser-
voir. Water will significantly lower the boil-
ing point of the brake fluid and could
cause vapor lock.
ECA13540
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.4. Bleed:
• Brake system
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21.
5. Check:
• Brake fluid level
The minimum level mark “a” or below 
Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-26.
6. Check:
• Brake lever free play
Refer to “ADJUSTING THE FRONT
BRAKE” on page 3-22.
• Brake lever operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21.
Recommended brake fluid
DOT 4

REAR BRAKE
4-28
WARNING
• Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
brake performance.
• Refill with the same type of brake fluid that
is already in the system. Mixing brake flu-
ids may result in a harmful chemical reac-
tion, leading to poor brake performance.
• When refilling, be careful that water does
not enter the brake fluid reservoir. Water
will significantly lower the boiling point of
the brake fluid and could cause vapor
lock.
ECA13540
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
5. Bleed:
• Brake system
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21.
6. Check:
• Brake fluid level
The minimum level mark “a” or below 
Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-26.
7. Check:
• Brake pedal operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21.
EAS1SL5158
REMOVING THE REAR BRAKE MASTER
CYLINDER
TIP
Before removing the rear brake master cylin-
der, drain the brake fluid from the entire brake
system.
1. Remove:
• Union bolt
• Copper washers
• Brake hose
TIP
To drain any remaining brake fluid, place a con-
tainer under the master cylinder and the end of
the brake hose.
EAS1SL5159CHECKING THE REAR BRAKE MASTER
CYLINDER
1. Check:
• Brake master cylinder “1”
Damage/scratches/wear  Replace.
• Brake fluid delivery passages “2”
(brake master cylinder body)
Obstruction  Blow out with compressed
air.
2. Check:
• Brake master cylinder kit
Damage/wear  Replace.
3. Check:
• Master cylinder reservoir cap
Crack/damage  Replace.
• Brake master cylinder reservoir diaphragm
holder
• Brake master cylinder reservoir diaphragm
Crack/damage  Replace.
4. Check:
• Brake hoses
Cracks/damage/wear  Replace.
a
1
2

REAR BRAKE
4-30
2. Pour brake fluid to the brake fluid reservoir
up to the specified level.
EWA13090
WARNING
• Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
brake performance.
• Refill with the same type of brake fluid that
is already in the system. Mixing brake flu-
ids may result in a harmful chemical reac-
tion, leading to poor brake performance.
• When refilling, be careful that water does
not enter the brake fluid reservoir. Water
will significantly lower the boiling point of
the brake fluid and could cause vapor
lock.
ECA13540
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
3. Bleed:
• Brake system
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21.
4. Check:
• Brake fluid level
The minimum level mark “a” or below 
Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-26.5. Check:
• Brake pedal operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21. Recommended brake fluid
DOT 4
a
a

HANDLEBAR
4-35
6. Install:
• Right grip “1”
• Collar “2”
Apply adhesive to the tube guide “3”.
TIP
• Before applying the adhesive, wipe off grease
or oil on the tube guide surface “a” with a lac-
quer thinner.
• Install the grip to the tube guide so that the
grip match mark “b” and tube guide slot “c”
form the angle as shown.
7. Install:
• Collar “1”
• Rubber cover “2”
• Throttle grip “3”
TIP
Apply the lithium soap base grease on the
throttle grip sliding surface.8. Install:
• Throttle cables “1”
TIP
Slightly coat the end of throttle cable and inside
of throttle grip with lithium-soap-based grease.
Then, mount the throttle grip onto the handle-
bar.
9. Install:
• Throttle cable housings “1”
• Screw (throttle cable housings) “2”
EWA1DX5001
WARNING
After tightening the throttle cable housing
screws, check that the throttle grip “3”
moves smoothly. If it does not, retighten the
screws for adjustment.
1b
c
3
Screw (throttle cable housings)
3.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
T R..

FRONT FORK
4-38
Disassembling the front fork leg
Order Part name Q’ty Remarks
1Adjuster 1
2 Fork spring 1
3 Dust seal 1
4 Stopper ring 1
5 Inner tube 1
6 Outer tube 1
7 Piston metal 1
8Protector guide 1
9 Slide metal 1
10 Washer 1
11 Oil seals 1
12 Base valve 1
13 Damper assembly 1
For assembly, reverse the disassemble pro-
cedure.
LS
13
2 6
9 8
10 11
4
3 1 57
12
New
NewNew
New
New
New
New
LT
29 Nm (2.9 mkgf, 21 ftIbf)T.R.
55 Nm (5.5 mkgf, 40 ftIbf)T.R.1.3 Nm (0.13 mkgf, 0.94 ftIbf)T.R.
28 Nm (2.8 mkgf, 20 ftIbf)T.R.
30 Nm (3.0 mkgf, 22 ftIbf)T.R.

FRONT FORK
4-39
EAS1SL5167REMOVING THE FRONT FORK LEGS
1. Use a suitable stand to raise the front wheel
off the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
TIP
Record the adjusting screw setting position be-
fore loosening the adjuster and the base valve.
2. Loosen:
• Upper bracket pinch bolts
• Damper assembly
• Lower bracket pinch bolts
EWA13640
WARNING
Before loosening the upper and lower
bracket pinch bolts, support the front fork
leg.
TIP
Before removing the front fork leg from the ve-
hicle, loosen the damper assembly “1” with the
cap bolt ring wrench “2”.
3. Remove:
• Front fork leg (s)
EAS1SL5168DISASSEMBLING THE FRONT FORK LEGS
1. Drain:
• Fork oil
2. Remove:
• Adjuster “1”
(from the inner tube)
TIP
• While compressing the inner tube “2”, set the
cap bolt ring wrench “4” between the inner
tube and locknut “3”.
• Hold the locknut and remove the adjuster.
ECA14180
NOTICE
Do not scratch the inner tube.
3. Remove:
• Dust seal “1”
• Oil seal clip “2”
(with a flat-head screwdriver)
ECA14180
NOTICE
Do not scratch the inner tube.
4. Remove:
• Inner tube “1”
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a. Push in slowly “a” the inner tube just before
it bottoms out and then pull it back quickly
“b”.
b. Repeat this step until the inner tube can be
pulled out from the outer tube.
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Cap bolt ring wrench
90890-01501
YM-01501
12
Cap bolt ring wrench
90890-01501
YM-01501
1
234
1
2