2016 YAMAHA WR 450F air bleeding

3
PERIODIC CHECKS AND ADJUSTMENTS
PERIODIC MAINTENANCE............................................................................. 3-1
INTRODUCTION ........................................................................................ 3-1
PERIODIC MAINTENANCE CHART FOR THE EMISSION
CONTROL SYSTEM ....................... .......................................................... 3-1
GENERAL MAINTENANCE AND LUBRICATION CHART ........................ 3-2
MAINTENANCE INTERVALS FOR COMPETITION USE ......................... 3-4
PRE-OPERATION INSPECTION AND MAINTENANCE ................................. 3-9
GENERAL INSPECTION AND MAINTENANCE........................................ 3-9
ENGINE .......................................................................................................... 3-10
CHECKING THE COOLANT LEVEL ........................................................ 3-10
CHECKING THE COOLING SYSTEM ..................................................... 3-10
CHANGING THE COOLANT.................................................................... 3-10
CHECKING THE RADIATOR CAP .......................................................... 3-11
CHECKING THE RADIATOR CAP VALVE OPENING PRESSURE ....... 3-11
CHECKING THE COOLANT CIRCULATORY SYSTEM FOR LEAKS .... 3-12
ADJUSTING THE CLUTCH LEVER FREE PLAY .................................... 3-12
ADJUSTING THE THROTTLE GRIP FREE PLAY .................................. 3-13
LUBRICATING THE THROTTLE CABLE ................................................ 3-14
CLEANING THE AIR FILTER ELEMENT................................................. 3-14
CHECKING THE THROTTLE BODY JOINT ............................................ 3-15
CHECKING THE BREATHER HOSES .................................................... 3-15
CHECKING THE EXHAUST SYSTEM............................. ........................ 3-15
CHECKING THE FUEL LINE ................................................................... 3-16
CHECKING THE ENGINE OIL LEVEL............................. ........................ 3-16
CHANGING THE ENGINE OIL ................................................................ 3-17
ADJUSTING THE ENGINE IDLING SPEED ......... ................................... 3-19
ADJUSTING THE VALVE CLEARANCE ................................................. 3-20
CLEANING THE SPARK ARRESTER ..................................................... 3-24
CHASSIS ........................................................................................................ 3-25
BLEEDING THE BRAKE SYST EM .......................................................... 3-25
CHECKING THE BRAKE HOSE .............................................................. 3-26
ADJUSTING THE FRONT BRAKE .......................................................... 3-26
ADJUSTING THE REAR BRAKE ............................................................. 3-27
CHECKING THE FRONT BR AKE PADS ................................................. 3-27
CHECKING THE REAR BRAKE PADS ........................... ........................ 3-29
CHECKING THE REAR BRAKE PAD INSULATOR ................................ 3-30
CHECKING THE BRAKE FLUID LEVEL.................................................. 3-30
ADJUSTING THE DRIVE CHAIN SLACK ................................................ 3-31
CHECKING THE FRONT FORK LEGS ................................................... 3-31
CHECKING THE FRONT FORK PROTECTOR GUIDE .......................... 3-32
CLEANING THE FRONT FORK OI L SEAL AND DUST SEAL ................ 3-32
AIR BLEEDING FROM FRONT FORK .................................................... 3-32
ADJUSTING THE FRONT FORK LEGS .................................................. 3-33
CHECKING THE SWINGARM OPERATION ........................................... 3-34
CHECKING THE REAR SUSPENSION ................................................... 3-34

CHASSIS
3-25
EAS2GC1101
CHASSIS
EAS2GC1102BLEEDING THE BRAKE SYSTEMEWA
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.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
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
• Wipe off any brake fluid on the brake discs, tires, wheels, etc.
• 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 3-30.
EWA
WARNING
After bleeding the hydraulic brake system,
check the brake operation.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
1
2
A
A. Front
B. Rear
Bleed screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
2
1B
T R..

CHASSIS
3-26
EAS2GC1103CHECKING 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 hosesBrake fluid leaks  Replace the damaged
brake hose.
Refer to “FRONT BRAKE” on page 5-13.
Refer to “REAR BRAKE” on page 5-23.
EAS2GC1104ADJUSTING THE FRONT BRAKE
1. Check: • Brake lever position “a” 2. Remove:
• Brake lever cover
3. Adjust: • Brake lever position
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
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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4. Install: • Brake lever cover
A. Front
B. Rear
Brake lever position95 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.
Locknut5 Nm (0.5 m·kgf, 3.6 ft·lbf)
a
b
T R..

CHASSIS
3-32
3. Hold the vehicle upright and apply the front brake.
4. Check:
• Front fork operationPush 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 5-40.
EAS2GC1112CHECKING 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.
EAS2GC1113CLEANING 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.
EAS2GC1114AIR 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

FRONT BRAKE
5-20
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
5. Bleed:• Brake systemRefer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-25.
6. Check: • Brake fluid level
The minimum level mark or below  Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-30.
7. Check: • Brake lever free playRefer to “ADJUSTING THE FRONT
BRAKE” on page 3-26.
• Brake lever operation A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-25.
EAS2GC1176REMOVING 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.
EAS2GC1177CHECKING 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 hosesCracks/damage/wear  Replace.
EAS2GC1178ASSEMBLING THE FRONT BRAKE MAS-
TER CYLINDER
EWA
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”.
EWA
WARNING
Apply brake fluid to the cylinder cups and
install them as shown. Wrong orientation in
installation causes poor braking perfor-
mance. Specified brake fluid
DOT 4
1
2

REAR BRAKE
5-30
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.
5. Bleed:• Brake system
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-25.
6. Check:
• Brake fluid levelThe minimum level mark “a” or below 
Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-30.
7. Check: • Brake pedal operationA softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-25.
EAS2GC1189REMOVING 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.
EAS2GC1190CHECKING 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 capCrack/damage  Replace.
• Brake master cylinder reservoir diaphragm holder
• Brake master cylinder reservoir diaphragm
Crack/damage  Replace.
4. Check: • Brake hoses
Cracks/damage/wear  Replace.
EAS2GC1191ASSEMBLING THE REAR BRAKE MASTER
CYLINDER
EWA
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.
a
1 2