2014 YAMAHA YZ450F oil

CHASSIS
3-27
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 pouring the brake fluid, be careful
that water does not enter the reservoir.
Water will significantly lower the boiling
point of the brake fluid and could cause
vapor lock.
ECA13540
NOTICE
Immediately wipe off the spilled brake fluid
to avoid damage to painted surfaces or
plastic parts.
EAS1SL1098ADJUSTING THE DRIVE CHAIN SLACKECA13550
NOTICE
A drive chain that is too tight will overload
the engine and other vital parts, and one
that is too loose can skip and damage the
swingarm or cause an accident. Therefore,
keep the drive chain slack within the speci
-
fied limits.
1. Use a suitable stand to raise the rear wheel
off the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Shift the transmission into the neutral posi-
tion.
3. Pull the drive chain up above the drive chain
guide installation bolt with a force of about
50 N (5.0 kgf, 36 lbf).
4. Check:
• Drive chain slack “a”
Out of specification  Regulate.
TIP
Measure drive chain slack between the drive
chain guide and the bottom of the chain as
shown.
5. Adjust:
• Drive chain slack
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Loosen the wheel axle nut “1.”
b. Loosen both locknuts “2.”
c. Turn the drive chain puller “3” in direction “a”
or “b” until the specified drive chain slack is
obtained.
TIP
• To maintain the proper wheel alignment, ad-
just both sides evenly.
• Push the rear wheel forward to make sure that
there is no clearance between the swingarm
end plates and the ends of the swingarm.
d. Tighten the locknut.
e. Tighten the wheel axle nut.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
Drive chain slack
50–60 mm (1.97–2.36 in)
Direction “a”
The drive chain slack decreases.
Direction “b”
The drive chain slack increases.
Locknut
21 Nm (2.1 m·kgf, 15 ft·lbf)
Wheel axle nut
135 Nm (13.5 m·kgf, 98 ft·lbf)
a
1
32
a
b
T R..
T R..

CHASSIS
3-28
EAS1SL1099CHECKING THE FRONT FORK LEGS
1. Stand the vehicle upright on a level surface.EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Check:
• Inner tube
Damage/scratches  Replace.
• Front fork leg (s)
Oil leaks between inner tube and outer tube
 Replace the oil seal.
3. Hold the vehicle upright and apply the front
brake.
4. Check:
• Front fork operation
Push down hard on the handlebar several
times and check if the front fork rebounds
smoothly.
Unsmooth operation  Correct or replace.
Refer to “FRONT FORK” on page 4-37.
EAS1SL1100CHECKING THE FRONT FORK PROTEC-
TOR GUIDE
1. Check:
• Protector guide “1”
Out of specification  Replace.
TIP
The protector guide reaches the limit of its use
when it is worn down to the same height “a” as
of the outer tube circumference.
EAS1SL1101
CLEANING THE FRONT FORK OIL SEAL
AND DUST SEAL
1. Remove:
•Protector
• Dust seal “1”ECA?
NOTICE
Be careful not to damage the dust seal and
the inner tube by a driver.
2. Clean:
• Dust seal “a”
• Oil seal “b”
TIP
• Clean the dust seal and oil seal after every
run.
• Apply lithium-soap-based grease on the inner
tube.
EAS1SL1102AIR BLEEDING FROM FRONT FORK
TIP
If the front fork initial movement feels stiff dur-
ing a run, relieve the front fork internal pres-
sure.
1. Use a suitable stand to raise the front wheel
off the ground.
EWA@
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Remove the air bleed screw “1” and release
the internal pressure from the front fork.
1
a
1
LS
a
b

CHASSIS
3-30
CHECKING THE SWINGARM OPERATION
1. Check:
• Swingarm smooth action
• Swingarm free play
Refer to “SWINGARM” on page 4-60.
EAS1SL1105CHECKING THE REAR SUSPENSION
1. Stand the vehicle upright on a level surface.EWA@
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Check:
• Rear shock absorber assembly
Gas leaks/oil leaks  Replace the rear
shock absorber assembly.
Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 4-53.
3. Check:
• Rear shock absorber assembly smooth ac-
tion
• Rear suspension link smooth action
Sit astride the seat and shake your body up
and down several times to check whether
the rear shock absorber assembly operates
smoothly.
Unsmooth operation  Correct or replace.
Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 4-53.
EAS1SL1106ADJUSTING THE REAR SHOCK ABSORB-
ER ASSEMBLY
Use a suitable stand to raise the rear wheel off
the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
Spring preloadECA13590
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.
1. Remove:
• Rear frame
Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 4-53.
2. Adjust:
• Spring preload
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Loosen the locknut “1.”
b. Loosen the adjuster “2” until there is some
clearance between the spring and the ad
-
juster.
c. Measure the spring free length “a.”
d. Turn the adjuster in the direction of “b” or “c”
to make an adjustment.
TIP
• Be sure to remove all dirt and mud from
around the locknut and adjusting ring before
adjustment.
• The length of the spring (installed) changes
1.5 mm (0.06 in) per turn of the adjusting ring.
Direction “b”
Spring preload is increased (suspen-
sion is harder).
Direction “c”
Spring preload is decreased (suspen-
sion is softer).
Spring installed length “d”
Minimum
Position in which the spring is
turned in 1.5 mm (0.06 in) from
its free length.
STD
Position in which the spring is
turned in 10 mm (0.39 in) from its
free length.
Maximum
Position in which the spring is
turned in 18 mm (0.71 in) from its
free length.

FRONT WHEEL
4-3
EAS1SL1122
FRONT WHEEL
Removing the front wheel
OrderPart nameQ’tyRemarks
Use a suitable stand to raise the front wheel
off the ground.
1Front wheel axle pinch bolt4Loosen.
2Front wheel axle nut1
3Front wheel axle1
4Front wheel1
5Collars2
6Oil seals2
7Bearing2
8Brake disc1
For installation, reverse the removal proce-dure.
12 Nm (1.2 mkgf, 8.7 ftIbf)T.R.
New
New
LT
LS
LS
LS
5
76
5 6 7
(6)
8
12
1 3
21 Nm (2.1 mkgf, 15 ftIbf)T.R.
21 Nm (2.1 mkgf, 15 ftIbf)T.R.
4
115 Nm (11.5 mkgf, 83 ftlbf)T.R.

FRONT WHEEL
4-4
EAS1SL1123REMOVING THE FRONT WHEEL
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.
2. Remove:
• Front wheel
EAS1SL1124CHECKING THE FRONT WHEEL
1. Check:
• Front wheel axle
Roll the front wheel axle on a flat surface.
Bends  Replace.
EWA13460
WARNING
Do not use a bent front wheel axle even after
correcting this.
2. Check:
•Tire (s)
• Front wheel
Damage/wear  Replace
Refer to “CHECKING THE TIRES” on page
3-32 and “CHECKING THE WHEELS” on
page 3-33.
3. Check:
• Spokes
Bend/damage  Replace.
Loose  Tighten.
Tap the spokes with a screwdriver.
TIP
A tight spoke will emit a clear, ringing tone; a
loose spoke will sound flat.
4. Tighten:
• Spokes
Refer to “CHECKING AND TIGHTENING
THE SPOKES” on page 3-32.
TIP
After tightening the spokes, measure the wheel
runout.
5. Measure:
• Wheel radial runout “a”
• Wheel lateral runout “b”
Out of specification  Repair/replace.
6. Check:
•Collars
Damage/wear  Replace
7. Check:
• Bearing
Front wheel turns roughly or is loose  Re-
place the wheel bearings.
• Oil seals
Damage/wear  Replace
Spokes
2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
Radial wheel runout limit
2.0 mm (0.08 in)
Lateral wheel runout limit
2.0 mm (0.08 in)
T R..
ab

FRONT WHEEL
4-5
EAS1SL1125DISASSEMBLING THE FRONT WHEEL
1. Remove:
• Oil seals
• Bearing
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Clean the outside of the front wheel hub.
b. Remove the oil seals “1” with a flat-head
screwdriver.
TIP
To prevent damaging the wheel, place a rag “2”
between the screwdriver and the wheel sur
-
face.
c. Remove the bearings with a bearing puller.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SL1126ASSEMBLING THE FRONT WHEEL
1. Install:
• Bearing (left side) “1”
• Spacer “2”
• Bearing (right side) “3”
• Oil seals “4”
TIP
• Apply the lithium soap base grease to the
bearing and the oil seal lip when installing.
• Left side of bearing shall be installed first.
• Install the oil seal with its manufacture's
marks or numbers facing outward.
ECA1DX1005
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.
12
New
Brake disc bolt
12 Nm (1.2 m·kgf, 8.7 ft·lbf)
LOCTITE®
4
3
2
1
4
New
New
1
T R..

FRONT WHEEL
4-6
3. Install:
• Collar “1”
TIP
Apply the lithium soap base grease on the oil
seal lip.
EAS1SL1127INSTALLING THE FRONT WHEEL
1. Install:
• Front wheel
TIP
Install the brake disc “1” between the brake
pads “2” correctly.
2. Install:
• Front wheel axle “1”
TIP
Apply the lithium soap base grease to the front
wheel axle.
3. Tighten:
• Front wheel axle nut “1”
ECA14140
NOTICE
Before tightening the front wheel axle nut,
push down hard on the handlebar(s) several
times and check if the front fork rebounds
smoothly.
4. Tighten:
• Front wheel axle pinch bolt “1”
1
LS
Front wheel axle nut
115 Nm (11.5 m·kgf, 83 ft·lbf)
Front wheel axle pinch bolt
21 Nm (2.1 m·kgf, 15 ft·lbf)
T R..
1
T R..
1 1

REAR WHEEL
4-7
EAS1SL1128
REAR WHEEL
Removing the rear wheel
OrderPart nameQ’tyRemarks
Use a suitable stand to raise the rear wheel
off the ground.
1Nut (rear wheel axle)1
2Rear wheel axle1
3Drive chain puller2
4REAR WHEEL1
5Collars2
6Rear wheel sprocket1
7Oil seals2
8Circlip1
9Bearing3
10Brake disc1
For installation, reverse the removal proce-dure.
(6)
21 Nm (2.1 m•kgf, 15 ft•Ibf)T.R.
2 5
7 9
LS
LS(6)
46
1
(6) 3
LS
8
9 10
7 5
LT
14 Nm (1.4 m•kgf, 10 ft•Ibf)T.R.
3
21 Nm (2.1 m•kgf, 15 ft•Ibf)T.R.
42 Nm (4.2 m•kgf, 30 ft•Ibf)T.R.
135 Nm (13.5 m•kgf, 98 ft•lbf)T.R.