2014 YAMAHA YZ450F steering

PRE-OPERATION INSPECTION AND MAINTENANCE
3-7
EAS1SL1067
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
EAS1SL1068GENERAL INSPECTION AND MAINTENANCE
TIP
Perform usual maintenance enough so that, in the race course, a confirmation of that and simple set-
ting adjustments may only be left, in order to get enough time to use effectively.
ITEMinspectPage
CoolantCheck that coolant is filled up to the radiator cap.
Check the cooling system for leakage.3-8 – 10
FuelCheck that a fresh gasoline is filled in the fuel tank.
Check the fuel line for leakage.1-22
Engine oilCheck that the oil level is correct. Check the crank-
case and oil line for leakage.3-14 – 16
Gear shifter and clutchCheck that gears can be shifted correctly in order and
that the clutch operates smoothly.3-10 – 11
Throttle grip/Housing
Check that the throttle grip operation and free play
are correctly adjusted. Lubricate the throttle grip and
housing, if necessary.
3-11 – 12
BrakesCheck the play of front brake and effect of front and
rear brake.3-21 – 27
Drive chainCheck drive chain slack and alignment. Check that
the drive chain is lubricated properly.3-27
4-64 – 65
WheelsCheck for excessive wear and tire pressure. Check
for loose spokes and have no excessive play.3-32 – 33
SteeringCheck that the handlebar can be turned smoothly and
have no excessive play.3-33 – 34
Front forks and rear
shock absorberCheck that they operate smoothly and there is no oil
leakage.3-28 – 32
Cables (wires)
Check that the clutch and throttle cables move
smoothly. Check that they are not caught when the
handlebars are turned or when the front forks travel
up and down.
—
Exhaust pipeCheck that the exhaust pipe is tightly mounted and
has no cracks.3-13 – 14
Rear wheel sprocketCheck that the rear wheel sprocket tightening bolt is
not loose.4-8 – 9
LubricationCheck for smooth operation. Lubricate if necessary. 3-12 , 3-34
Bolts and nutsCheck the chassis and engine for loose bolts and
nuts.1-25 – 26
Lead connectorsCheck that the AC magneto, ECU and ignition coil are
connected tightly.1-12 – 14
Settings
Is the machine set suitably for the condition of the rac-
ing course and weather or by taking into account the
results of test runs before racing? Are inspection and
maintenance completely done?10-1 – 8

CHASSIS
3-33
2. Tighten:
• Spokes
Use a spoke nipple wrench “1” for tighten-
ing.
TIP
• Do not give a half turn (180°) or more for one
tightening.
• Make sure that tightening after a break-in is
done until the initial looseness in nipples dis
-
appears.
• Make sure that tightening is done in stages,
not at a time.
EAS1SL1109CHECKING THE WHEELS
1. Check:
• Wheel (s)
Damage/out-of-round  Replace.EWA13260
WARNING
Never attempt to make any repairs to the
wheel.
TIP
After replacing a tire or a wheel, always bal-
ance the wheel.
EAS1SL1110CHECKING THE WHEEL BEARINGS
1. Check:
• Wheel bearings
“CHECKING THE FRONT WHEEL” on page
4-4and “CHECKING THE REAR WHEEL”
on page 4-8.
EAS1SL1111
CHECKING AND ADJUSTING THE STEER-
ING HEAD
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. Check:
• Steering head
Grasp the bottom of the front fork legs and
gently rock the front fork.
Blinding/looseness  Adjust the steering
head.
3. Remove:
• Handlebar
Refer to “HANDLEBAR” on page 4-31.
• Upper bracket
Refer to “STEERING HEAD” on page 4-49.
4. Adjust:
• Steering head
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the washer “1.”
b. After loosening the ring nut “2” with a steer-
ing nut wrench “3,” tighten it to the specified
torque.
TIP
• Set the torque wrench at a right angle to the
steering nut wrench.
• Move the steering to the left and right a couple
of times to check that it moves smoothly.
Spoke nipple wrench (6–7)
90890-01521
YM-01521
Spokes
2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
1
T R..
1

CHASSIS
3-34
c. Turn the front fork to the right and left a few
times, and make sure that the steering ro
-
tates smoothly. If it does not turn smoothly,
remove the lower bracket and check the up
-
per and lower bearings.
Refer to “STEERING HEAD” on page 4-49.
d. Loosen the ring nut fully turn and then tight-
en it to specification with a steering nut
wrench.
EWA13140
WARNING
Do not overtighten the ring nut beyond the
specified torque. Otherwise, the steering
may malfunction.
e. Check the steering head for looseness or
binding by turning the front fork all the way in
both directions. If any binding is felt, remove
the lower bracket and check the upper and
lower bearings.
Refer to “STEERING HEAD” on page 4-49.
f. Install the washer “1”.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
5. Install:
• Upper bracket
Refer to “STEERING HEAD” on page 4-49.
• Handlebar
Refer to “HANDLEBAR” on page 4-31.
EAS1SL1112LUBRICATING THE LEVERS
1. Lubricate the pivoting points and metal-to-
metal moving parts of the following parts.
•Brake lever
• Clutch lever
EAS1SL1113LUBRICATING THE PEDAL
1. Lubricate the pivoting point and metal-to-
metal moving parts of the pedal.
Steering nut wrench
90890-01403
Exhaust flange nut wrench
YU-A9472
Ring nut (initial tightening torque)
38 Nm (3.8 m·kgf, 27 ft·lbf)
Ring nut (final tightening torque)
7 Nm (0.7 m·kgf, 5.1 ft·lbf)
3
2
T R..
T R..
1
Recommended lubricant
Silicone grease
Recommended lubricant
Lithium-soap-based grease
Recommended lubricant
Lithium-soap-based grease

HANDLEBAR................................................................................................. 4-31
REMOVING THE HANDLEBAR............................................................... 4-33
CHECKING THE HANDLEBAR ............................................................... 4-33
INSTALLING THE HANDLEBAR ............................................................. 4-33
FRONT FORK................................................................................................. 4-37
REMOVING THE FRONT FORK LEGS ................................................... 4-39
DISASSEMBLING THE FRONT FORK LEGS ......................................... 4-39
CHECKING THE FRONT FORK LEGS ................................................... 4-40
ASSEMBLING THE FRONT FORK LEGS ............................................... 4-41
INSTALLING THE FRONT FORK LEGS ................................................. 4-47
STEERING HEAD........................................................................................... 4-49
REMOVING THE LOWER BRACKET...................................................... 4-50
CHECKING THE STEERING HEAD ........................................................ 4-50
INSTALLING THE STEERING HEAD ...................................................... 4-50
REAR SHOCK ABSORBER ASSEMBLY..................................................... 4-53
HANDLING THE REAR SHOCK ABSORBER ......................................... 4-56
DISPOSING OF A REAR SHOCK ABSORBER ...................................... 4-56
REMOVING THE REAR SHOCK ABSORBER ASSEMBLY.................... 4-56
REMOVING THE BEARING..................................................................... 4-56
CHECKING THE REAR SHOCK ABSORBER ASSEMBLY .................... 4-57
CHECKING THE CONNECTING ARM AND RELAY ARM ...................... 4-57
INSTALLING THE RELAY ARM............................................................... 4-57
INSTALLING THE REAR SHOCK ABSORBER ASSEMBLY .................. 4-58
SWINGARM.................................................................................................... 4-60
REMOVING THE SWINGARM................................................................. 4-61
REMOVING THE BEARING..................................................................... 4-61
CHECKING THE SWINGARM ................................................................. 4-61
INSTALLING THE SWINGARM ............................................................... 4-62
CHAIN DRIVE................................................................................................. 4-63
REMOVING THE DRIVE CHAIN.............................................................. 4-64
CHECKING THE DRIVE CHAIN .............................................................. 4-64
CHECKING THE DRIVE SPROCKET...................................................... 4-65
CHECKING THE REAR WHEEL SPROCKET ......................................... 4-65
INSTALLING THE DRIVE CHAIN ............................................................ 4-65

STEERING HEAD
4-49
EAS1SL1171
STEERING HEAD
Removing the lower bracket
OrderPart nameQ’tyRemarks
Use a suitable stand to raise the front wheel
off the ground.
Number plateRefer to “GENERAL CHASSIS” on page 4-1.
HandlebarRefer to “HANDLEBAR” on page 4-31.
1Front fender1
2Steering stem nut1
3Front fork leg (s)2Refer to “FRONT FORK” on page 4-37.
4Upper bracket1
5Steering ring nut1
6Lower bracket1
7Bearing race cover1
8Upper bearing1
9Bearing (lower side)1
10Bearing races2
For installation, reverse the removal proce-dure.
2
4
5
7
3
1
6
8
9
10
LS
1st
2ndT.R.
LS
LS
T.R.21 Nm (2.1 mlbf) kgf, 15 ft
T.R.9 Nm (0.9 mlbf) kgf, 6.5 ft
T.R.21 Nm (2.1 mlbf) kgf, 15 ft
T.R.10 Nm (1.0 mlbf) kgf, 7.2 ft
T.R.145 Nm (14.5 mlbf) kgf, 105 ft
38 Nm (3.8 m
lbf) kgf, 27 ft
7 Nm (0.7 m
lbf) kgf, 5.1 ft

STEERING HEAD
4-50
EAS1SL1172REMOVING THE LOWER BRACKET
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:
• Ring nut “1”
TIP
Remove the ring nut with the steering nut
wrench “2”.
EWA13730
WARNING
Securely support the lower bracket so that
there is no danger of it falling.
EAS1SL1173CHECKING THE STEERING HEAD
1. Wash with kerosene:
• Bearing
• Bearing races
2. Check:
• Bearing
• Bearing races
Damage/pitting  Replace.
3. Replace:
• Bearing
• Bearing races
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the bearing race from the steering
head pipe with a long rod “1” and a hammer.
b. Remove the bearing race from the lower
bracket with a chisel “2” and a hammer.
c. Install a new bearing race.ECA14270
NOTICE
• Take care not to damage the steering shaft
thread.
• If the bearing race is not installed properly,
the steering head pipe could be damaged.
TIP
Always replace the bearing and the bearing
race as a set.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
4. Check:
• Upper bracket
• Lower bracket
(along with the steering stem)
Bends/cracks/damage  Replace.
EAS1SL1174INSTALLING THE STEERING HEAD
1. Install:
• Lower bearing “1”
TIP
Apply the lithium soap base grease on the dust
seal lip and bearing inner circumference.
Steering nut wrench
90890-01403
Exhaust flange nut wrench
YU-A9472

STEERING HEAD
4-51
2. Install:
• Bearing races
• Upper bearing “1”
• Bearing race cover “2”
TIP
Apply the lithium soap base grease on the
bearing and bearing race cover lip.
3. Install:
• Lower bracket “1”
TIP
Apply the lithium soap base grease on the
bearing, the portion “a” and thread of the steer
-
ing stem.
4. Install:
• Steering ring nut “1”
TIP
Install the steering nut with its stepped side “a”
facing downward.
Tighten the steering ring nut with a steering
nut wrench “2.”
Refer to “CHECKING AND ADJUSTING
THE STEERING HEAD” on page 3-33.
5. Check the steering stem by turning this lock
to lock. If there is any binding, remove the
steering stem and check the steering bear
-
ing.
6. Install:
• Washer “1”
7. Install:
• Front fork “1”
• Upper bracket “2”
TIP
• Temporarily tighten the pinch bolts (lower
bracket).
• Do not tighten the pinch bolts (upper bracket)
yet.
Steering ring nut
7 Nm (0.7 m·kgf, 5.1 ft·lbf)
LS
1 a
LSLS
T R..

STEERING HEAD
4-52
8. Install:
• Steering stem nut “1”
TIP
Apply the lithium soap base grease to the con-
tact surface of the steering stem nut when in-
stalling.
9. After tightening the nut, check the steering
for smooth movement. If not, adjust the
steering by loosening the steering ring nut
little by little.
10.Adjust:
• Front fork top end “a”
11.Tighten:
• Pinch bolt (upper bracket) “1”
• Pinch bolt (lower bracket) “2”
EWA33DD049
WARNING
Tighten the lower bracket to specified
torque. If torqued too much, it may cause
the front fork to malfunction.Steering stem nut
145 Nm (14.5 m·kgf, 105 ft·lbf)
Front fork top end (standard) “a”
0 mm (0 in)
T R..
a
Upper bracket pinch bolts
21 Nm (2.1 m·kgf, 15 ft·lbf)
Lower bracket pinch bolts
21 Nm (2.1 m·kgf, 15 ft·lbf)
T R..
T R..
21