warning YAMAHA YZ450F 2016 User Guide

ENGINE
3-16
d. Install the oil strainer.
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6. Install:
• Engine oil drain bolt
• Drain bolt
7. Pour the specified amount of engine oil into
the oil filler cap hole.
8. Install:
• Oil filler cap
9. Check:
• Oil level
Refer to “CHECKING THE ENGINE OIL
LEVEL” on page 3-14.
10.Check:
• Engine oil pressure
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a. Slightly loosen the oil pressure check bolt
“1”.
EWA
WARNING
When the engine is started with the check
bolt removed, oil will spout; therefore, al-
ways loosen it before the checkup.
Start the engine and keep it idling until oil
starts to seep from the oil pressure check
bolt.
EWA
WARNING
Always keep the engine idling speed during
the checkup without increasing the engine
speed.
ECA
NOTICE
If no engine oil seeps out after one minute,
immediately turn the engine off so it will not
seize.
b. If no engine oil seeps out, check the engine
oil for leaks, and the engine oil passage and
the oil pump for damage.
c. Check the oil pressure again.
d. Tighten the oil pressure check bolt.
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TIP
• Because the air pressure is lower at high alti-
tudes, the air-fuel mixture will become richer.
If the idling speed is low, turn the starter knob/
idle screw a few clicks counterclockwise to in-
crease the speed before the adjustment.
• Before adjusting the engine idling speed,
make sure that the air filter element is not
clogged, the engine compression is proper,
and the throttle grip free play is proper.
• Adjust the engine idling speed with the starter
knob/idle screw pushed in completely. Oil strainer bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Drain bolt
20 Nm (2.0 m·kgf, 14 ft·lbf)
Engine oil quantity
With oil filter element replace-
ment
0.69 L (0.73 US qt, 0.61 Imp.qt)
Quantity (disassembled)
0.95 L (1.00 US qt, 0.84 Imp.qt)
1
2New
T R..
New
T R..
Oil pressure check bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
1
T R..

CHASSIS
3-22
EASB111088
CHASSIS
EASB111089BLEEDING THE BRAKE SYSTEMEWA13100
WARNING
Bleed the brake system whenever:
• The system is disassembled.
• A brake hose is loosened, disconnected,
or replaced.
• The brake fluid level is very low.
• Brake operation is faulty.
1. Remove:
• Brake master cylinder cap
• Reservoir diaphragm
• Reservoir float (front brake)
• Protector (rear brake)
TIP
• Be careful not to spill any brake fluid or allow
the reservoir to overflow.
• Make sure that there is enough brake fluid be-
fore applying the brake. Ignoring this precau-
tion could allow air to enter the brake system,
considerably lengthening the bleeding proce-
dure.
• If bleeding is difficult, it may be necessary to
let the brake fluid settle for a few hours. Re-
peat the bleeding procedure when the tiny
bubbles in the hose have disappeared.
2. Bleed the brake system.
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a. Fill the reservoir to the proper level with the
recommended brake fluid.
b. Install the reservoir diaphragm.
c. Connect the plastic hose “1” to the bleed
screw “2” securely, and place a container
under the end of the plastic hose.d. Slowly apply the brake several times.
e. Fully pull the brake lever or fully press down
the brake pedal and hold it in position.
f. Loosen the bleed screw.
TIP
Loosening the bleed screw will release the
pressure in the brake caliper and cause the
brake lever to contact the throttle grip or the
brake pedal to fully extend.
g. Tighten the bleed screw and then release
the brake lever or brake pedal.
h. Repeat steps (d) to (g) until all of the air bub-
bles have disappeared from the brake fluid
in the plastic hose.
TIP
During the procedure, keep adding brake fluid
to the reservoir.
ECA
NOTICE
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
i. Tighten the bleed screw.
j. Pour brake fluid to the reservoir up to the
specified level.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-27.
EWA13110
WARNING
After bleeding the hydraulic brake system,
check the brake operation.
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1 2
A
A. Front
B. Rear
Bleed screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
2
1B
T R..

CHASSIS
3-23
EASB111090CHECKING THE BRAKE HOSE
1. Check:
• Brake hose “1”
Cracks/damage/wear  Replace.
2. Check:
• Brake hose clamp
Loose Connection  Tighten the clamp bolt.
3. Stand the vehicle upright and apply the front
brake and the rear brake several times.
4. Check:
• Brake hoses
Brake fluid leaks  Replace the damaged
brake hose.
Refer to “FRONT BRAKE” on page 4-12.
Refer to “REAR BRAKE” on page 4-22.
EASB111091ADJUSTING THE FRONT BRAKE
1. Check:
• Brake lever position “a”2. Remove:
• Brake lever cover
3. Adjust:
• Brake lever position
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a. Loosen the locknut “1”.
b. Turn the adjusting bolt “2” in direction “a” or
“b” until the specified brake lever position is
obtained.
c. Tighten the locknut.
EWA13050
WARNING
A soft or spongy feeling in the brake lever
can indicate the presence of air in the brake
system. Before the vehicle is operated, the
air must be removed by bleeding the brake
system. Air in the brake system will consid-
erably reduce braking performance.
ECA13490
NOTICE
After adjusting the brake lever position,
make sure there is no brake drag.
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A. Front
B. Rear
Brake lever position
95 mm (3.74 in)
Extent of adjustment
86–105 mm (3.39–4.13 in)
1
1
Direction “a”
Brake lever position is increased.
Direction “b”
Brake lever position is decreased.
Locknut
5 Nm (0.5 m·kgf, 3.6 ft·lbf)
a
b
T R..

CHASSIS
3-24
4. Install:
• Brake lever cover
EASB111092ADJUSTING THE REAR BRAKE
1. Check:
• Brake pedal position “a”
(distance from the top of the rider footrest to
the top of the brake pedal)
Out of specification  Regulate.
2. Adjust:
• Brake pedal position
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a. Loosen the locknut “1”.
b. Turn the adjusting bolt “2” in direction “a” or
“b” until the specified brake pedal position is
obtained.
c. Tighten the locknut.
EWA
WARNING
A soft or spongy feeling in the brake pedal
can indicate the presence of air in the brake
system. Before running, bleed the brake
system. Air in the brake system will cause
braking performance to be reduced.
ECA
NOTICE
After adjusting the brake pedal position,
make sure that there is no brake drag.
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EASB111093CHECKING THE FRONT BRAKE PADS
1. Measure:
• Brake pad thickness “a”
Out of specification  Replace as a set.
TIP
The pads worn up to the indicator “b” grooves
mean that the brake pad thickness limit is
reached. Brake pedal position
0.0 mm (0.00 in)
Direction “a”
Brake pedal is raised.
Direction “b”
Brake pedal is lowered.
Locknut
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
1 2
a
b
T R..
Brake pad lining thickness (inner)
4.4 mm (0.17 in)
Limit
1.0 mm (0.04 in)
Brake pad lining thickness (outer)
4.4 mm (0.17 in)
Limit
1.0 mm (0.04 in)
a
b
a

CHASSIS
3-25
2. Replace:
• Brake pads
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a. Remove the pad pin plug “1”.
b. Loosen the pad pin “2”.
c. Remove the brake caliper “3” from the front
fork.
d. Remove the pad pin and brake pads “4”.
e. Connect the plastic hose “5” to the bleed
screw “6” and place a container under the
end of the plastic hose.f. Loosen the bleed screw and push the brake
caliper piston in.
EWA
WARNING
Do not reuse the drained brake fluid.
g. Tighten the bleed screw.
h. Install the brake pads “7” and the pad pin.
TIP
• Install the brake pads with their projections “a”
into the brake caliper recesses “b”.
• Temporarily tighten the pad pin at this point.
i. Install the brake caliper “8” and tighten the
pad pin “9”.
j. Install the pad pin plug “10”.
1
3
2
4
6
5
Bleed screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
Bolt (brake caliper)
28 Nm (2.8 m·kgf, 20 ft·lbf)
Pad pin
17 Nm (1.7 m·kgf, 12 ft·lbf)
Pad pin plug
2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
T R..
7
a b
T R..
8
9
T R..

CHASSIS
3-27
f. Loosen the bleed screw and push the brake
caliper piston in.
EWA
WARNING
Do not reuse the drained brake fluid.
g. Tighten the bleed screw.
h. Install the brake pad “10” and the pad pin
“11”.
TIP
• Install the brake pads with their projections “a”
into the brake caliper recesses “b”.
• Temporarily tighten the pad pin at this point.
i. Install the brake caliper “12” and the rear
wheel “13”.
Refer to “REAR WHEEL” on page 4-7.
j. Tighten the pad pin “14”.
k. Install the pad pin plug “15” and the protector
“16”.
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3. Check:
• Brake fluid level
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-27.
4. Check:
• Brake pedal operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-22.
EASB111095CHECKING THE REAR BRAKE PAD INSU-
LATOR
1. Remove:
• Brake pads
Refer to “REAR BRAKE” on page 4-22.
2. Check:
• Rear brake pad insulator “1”
Damage  Replace.
EASB111096CHECKING THE BRAKE FLUID LEVEL
1. Stand the vehicle upright on a level surface.
TIP
In order to ensure a correct reading of the brake
fluid level, make sure that the top of the brake
fluid reservoir is horizontal. Bleed screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
Pad pin
17 Nm (1.7 m·kgf, 12 ft·lbf)
Pad pin plug
2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
Bolt (protector)
7 Nm (0.7 m·kgf, 5.1 ft·lbf)
T R..
10 11
a
b
T R..
13
14
12
T R..
15
16

CHASSIS
3-28
2. Check:
• Brake fluid level
The minimum level mark “a” or below 
Add.
EWA
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.
ECA
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
EASB111097ADJUSTING 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
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a. Loosen the wheel axle nut “1”.
b. Loosen both locknuts “2”.
c. Turn the adjusting bolt “3” in direction “a” or
“b” until the specified drive chain slack is ob-
tained. Specified brake fluid
DOT 4
A. Front brake
B. Rear brake
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.
a

CHASSIS
3-29
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.
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EASB111098CHECKING THE FRONT FORK LEGS
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:
• 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 4-38.
EASB111099CHECKING 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.
EASB111100CLEANING 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. Locknut
21 Nm (2.1 m·kgf, 15 ft·lbf)
Wheel axle nut
135 Nm (13.5 m·kgf, 98 ft·lbf)
1
32
a
b
T R..
T R..1
a
1

CHASSIS
3-30
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.
EASB111101AIR 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.
3. Tighten:
• Air bleed screw
EASB111102
ADJUSTING THE FRONT FORK LEGSEWA32D1006
WARNING
• Always adjust the left and right front forks
evenly. If this is not done, the vehicle may
have poor stability.
• Securely support the vehicle so that there
is no danger of it falling over.
Rebound damping
ECA@
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.
1. Adjust:
• Rebound damping
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a. Turn the adjuster “1” in the direction of “a” or
“b” to make an adjustment.
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Air bleed screw
1.3 Nm (0.13 m·kgf, 0.94 ft·lbf)
LS
a
b
T R..
1
Direction “a”
Rebound damping is increased (sus-
pension is harder).
Direction “b”
Rebound damping is decreased (sus-
pension is softer).
Rebound damping adjusting posi-
tions
Maximum
Fully turned in
Standard
11 clicks out*
Minimum
20 clicks out*
* With the adjuster fully turned in
1
a
b

CHASSIS
3-31
Compression dampingECA@
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.
1. Adjust:
• Compression damping
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a. Turn the adjuster “1” in the direction of “a” or
“b” to make an adjustment.
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EASB111103CHECKING THE SWINGARM OPERATION
1. Check:
• Swingarm smooth action
• Swingarm free play
Refer to “SWINGARM” on page 4-62.
EASB111104
CHECKING 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 4-55.
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 4-55.
EASB111105ADJUSTING 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 preload
ECA@
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.
1. Remove:
• Rear frame
Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 4-55. Direction “a”
Compression damping is increased
(suspension is harder).
Direction “b”
Compression damping is decreased
(suspension is softer).
Compression damping adjusting
positions
Maximum
Fully turned in
Standard
8 clicks out* (USA) (CAN)
16 clicks out* (EUR) (JPN) (AUS)
(NZL) (ZAF)
Minimum
20 clicks out*
* With the adjuster fully turned in
a b
1