2014 YAMAHA YZ450F oil level

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 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 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
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.
EAS1SL1144REMOVING 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.
EAS1SL1145CHECKING 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.
EAS1SL1146ASSEMBLING THE FRONT BRAKE MAS-
TER CYLINDEREWA13520
WARNING
• Before installation, clean and lubricate the
internal parts. Use new brake fluid for
cleaning and lubricating.
• 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
New
New

FRONT BRAKE
4-20
WARNING
Proper brake hose routing is essential to in-
sure safe vehicle operation. Refer to“CA-
BLE ROUTING DIAGRAM” on page 2-33.
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 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.
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 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
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.
EAS1SL1157
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.
EAS1SL1158CHECKING 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.
EAS1SL1159
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 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
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

FRONT FORK
4-41
5. Check:
• Base valve “1”
Wear/damage  Replace.
Contamination  Clean.
• O-rings “2”
Wear/damage  Replace.
• Base valve bushing “3”
Wear/damage  Replace.
• Spring “4”
Damage/fatigue  Replace the base valve.
• Air bleed screw “5”
Wear/damage  Replace.
6. Check:
• Contacting surface “a”
Wear/damage  Replace.
7. Check:
• Adjuster “1”
• O-rings “2”
Wear/damage  Replace.
EAS1SL1169ASSEMBLING THE FRONT FORK LEGSEWA13660
WARNING
• Make sure the oil levels in both front fork
legs are equal.
• Uneven oil levels can result in poor han-
dling and a loss of stability.
TIP
• When assembling the front fork leg, be sure to
replace the following parts:
• Inner tube bushing
• Outer tube bushing
• Oil seals
• Copper washers
• Before assembling the front fork leg, make
sure that all of the components are clean.
1. Stretch the damper assembly fully.
2. Fill:
• Damper assembly
ECA14210
NOTICE
• Be sure to use the recommended oil. Other
oils may have an adverse effect on front
fork performance.
• When disassembling and assembling the
front fork leg, take care not to allow any
foreign material to enter the front fork.
3. After filling, pump the damper assembly “1”
slowly up and down (about 200 mm (7.9 in)
stroke) several times to bleed the damper
assembly of air.
TIP
Avoid excessive full stroke. A stroke of 200 mm
(7.9 in) or more will cause air to enter. In this
case, repeat the steps 1 to 3.
21
New
New
New
2
21 543
a
New
Recommended oil
Suspension oil S1
Standard oil amount
204 cm3 (6.90 US oz, 7.20
Imp.oz)
New
1
2

FRONT FORK
4-42
4. Measure:
• Oil level (left and right) “a”
Out of specification  Regulate.
5. Tighten:
• Locknut “1”
TIP
Fully finger tighten the locknut onto the damper
assembly.
6. Loosen:
• Compression damping force adjuster “1”
TIP
• Before loosening the damping force adjuster,
record the setting position.
• Unless the damping force adjuster is fully
loosened, correct damping characteristic can
-
not be obtained after installation.
7. Install:
• Base valve “1”
(to the damper assembly “2”)
TIP
First bring the damper rod pressure to a maxi-
mum. Then install the base valve while releas-
ing the damper rod pressure.
8. Check:
• Damper assembly
Not fully stretched  Repeat the steps 1 to
7.
9. Tighten:
• Base valve “1”
TIP
Hold the damper assembly with the cap bolt
ring wrench “2” and use the cap bolt wrench “3”
to tighten the base valve.
Standard oil level
145-148 mm (5.71-5.83 in)
From top of fully stretched
damper assembly.
1
a
Base valve
28 Nm (2.8 m·kgf, 20 ft·lbf)
1
1
2
T R..