2014 YAMAHA YZ450F Owners Manual

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

ELECTRICAL SYSTEM
3-35
EAS1SL1114
ELECTRICAL SYSTEM
EAS1SL1115CHECKING THE SPARK PLUG
1. Remove:
• Seat
• Air scoop (left/right)
Refer to “GENERAL CHASSIS” on page 4-
1.
• Fuel tank “1”
Refer to “FUEL TANK” on page 7-1.ECA1DX1001
NOTICE
Do not use too much force to pull the hose.
TIP
Remove the fuel tank, turn this 180° clockwise,
and put it in the frame “2” as shown.
2. Remove:
• Spark plug cap
• Spark plug
Refer to “CAMSHAFT” on page 5-11.ECA13330
NOTICE
In order not to allow the dirt accumulated
around the spark plug to drop from the
spark plug hole into the cylinder, clean it be
-
fore removing the spark plug.
3. Check:
• Spark plug type
Wrong type  Replace.
4. Check:
• Electrode
Damage/wear  Replace the spark plug.
• Insulator
Abnormal color  Replace the spark plug.
Normal color is medium-to-light tan.
5. Clean:
• Spark plug
(with a spark plug cleaner or a wire brush)
6. Measure:
• Spark plug gap “a”
Out of specification  Adjust the spark plug
gap.
7. Install:
• Spark plug
TIP
Before installing the spark plug, clean the spark
plug and gasket surface.
8. Install:
• Spark plug cap
• Fuel tank
• Air scoop (left/right)
• Seat
• Side cover (left/right)
Refer to “GENERAL CHASSIS” on page 4-
1.
EAS1SL1116CHECKING THE IGNITION TIMING
1. Remove:
• Timing mark accessing screw “1”Manufacturer/model
NGK/CR8E
1
1
2
Spark plug gap
0.7–0.8 mm (0.028–0.031 in)
Spark plug
13 Nm (1.3 m·kgf, 9.4 ft·lbf)T R..
1

ELECTRICAL SYSTEM
3-36
2. Attach:
• Timing light “1”
• Digital tachometer “2”
To the high tension code “3”.
3. Adjust:
• Engine idling speed
Refer to “ADJUSTING THE ENGINE
IDLING SPEED” on page 3-16.
4. Check:
• Ignition timing
Check whether the alignment mark “a” on
the left crankcase cover is within the firing
range “b” on the rotor.
Incorrect firing range  Check rotor and
Crankshaft position sensor.
5. Install:
• Timing mark accessing screw
Timing light
90890-03141
YU-03141
Digital tachometer
90890-06760
YU-39951-B
Timing mark accessing screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
2
1
3
a
b
T R..

4
CHASSIS
GENERAL CHASSIS........................................................................................ 4-1
REMOVING THE LEFT SIDE COVER ....................................................... 4-2
REMOVING THE SEAT ............................................................................. 4-2
REMOVING THE NUMBER PLATE ........................................................... 4-2
FRONT WHEEL................................................................................................ 4-3
REMOVING THE FRONT WHEEL............................................................. 4-4
CHECKING THE FRONT WHEEL ............................................................. 4-4
DISASSEMBLING THE FRONT WHEEL ................................................... 4-5
ASSEMBLING THE FRONT WHEEL ......................................................... 4-5
INSTALLING THE FRONT WHEEL ........................................................... 4-6
REAR WHEEL.................................................................................................. 4-7
REMOVING THE REAR WHEEL ............................................................... 4-8
CHECKING THE REAR WHEEL................................................................ 4-8
DISASSEMBLING THE REAR WHEEL ..................................................... 4-8
CHECKING AND REPLACING THE REAR WHEEL SPROCKET ............ 4-8
ASSEMBLING THE REAR WHEEL ........................................................... 4-9
INSTALLING THE REAR WHEEL.............................................................. 4-9
FRONT BRAKE.............................................................................................. 4-11
INTRODUCTION ...................................................................................... 4-15
CHECKING THE FRONT BRAKE DISC .................................................. 4-15
REMOVING THE FRONT BRAKE CALIPER ........................................... 4-15
DISASSEMBLING THE FRONT BRAKE CALIPER................................. 4-15
CHECKING THE FRONT BRAKE CALIPER ........................................... 4-16
ASSEMBLING THE FRONT BRAKE CALIPER ....................................... 4-16
INSTALLING THE BRAKE CALIPER PISTON ........................................ 4-16
INSTALLING THE FRONT BRAKE CALIPER ......................................... 4-17
REMOVING THE FRONT BRAKE MASTER CYLINDER ........................ 4-18
CHECKING THE FRONT BRAKE MASTER CYLINDER......................... 4-18
ASSEMBLING THE FRONT BRAKE MASTER CYLINDER .................... 4-18
INSTALLING THE FRONT BRAKE MASTER CYLINDER....................... 4-19
REAR BRAKE................................................................................................ 4-21
INTRODUCTION ...................................................................................... 4-25
CHECKING THE REAR BRAKE DISC..................................................... 4-25
REMOVING THE REAR BRAKE CALIPER ............................................. 4-26
DISASSEMBLING THE REAR BRAKE CALIPER ................................... 4-26
CHECKING THE REAR BRAKE CALIPER .............................................. 4-26
ASSEMBLING THE REAR BRAKE CALIPER ......................................... 4-26
INSTALLING THE BRAKE CALIPER PISTON ........................................ 4-27
INSTALLING THE REAR BRAKE CALIPER ............................................ 4-27
REMOVING THE REAR BRAKE MASTER CYLINDER .......................... 4-28
CHECKING THE REAR BRAKE MASTER CYLINDER ........................... 4-28
ASSEMBLING THE REAR BRAKE MASTER CYLINDER....................... 4-29
INSTALLING THE REAR BRAKE MASTER CYLINDER ......................... 4-29

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

GENERAL CHASSIS
4-1
EAS1SL1117
TIP
This section is intended for those who have basic knowledge and skill concerning the servicing of
Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.). Those who have little knowl
-
edge and skill concerning servicing are requested not to undertake inspection, adjustment, disas-
sembly, or reassembly only by reference to this manual. It may lead to servicing trouble and
mechanical damage.
EAS1SL1118
GENERAL CHASSIS
Removing the seat and side cover
OrderPart nameQ’tyRemarks
1Seat1
2Air scoop (left)1
3Air scoop (right)1
4Side cover (left)1
5Side cover (right)1
6Number plate1
7Rear fender1
For installation, reverse the removal proce-dure.
4 (2)
75
1
3
6
2
7 Nm (0.7 m•kgf, 5.1 ftIbf)T.R.7 Nm (0.7 mkgf, 5.1 ftIbf)T.
R
.
7 Nm (0.7 mkgf, 5.1 ftIbf)T.R.
7 Nm (0.7 mkgf, 5.1 ftIbf)T.R.
22 Nm (2.2 mkgf, 16 ftIbf)T.R.
1.3 Nm (0.13 mkgf, 0.94 ftIbf)T.R.16 Nm (1.6 mkgf, 12 ftIbf)T.
R
.

GENERAL CHASSIS
4-2
EAS1SL1119REMOVING THE LEFT SIDE COVER
1. Remove:• Bolt (side cover)
• Side cover “1”
TIP
Draw the left side cover “1” backward to re-
move it because its projection “a” is inserted in
the rear frame.
EAS1SL1120REMOVING THE SEAT
TIP
The fuel tank cap cover and the seat are cou-
pled with each other with a plastic band.
When removing the seat, always remove the
fuel tank cap cover beforehand.
1. Remove:• Fuel tank cap cover “1”
Refer to “FUEL TANK CAP” on page 1-21.
2. Remove: • Seat “1”
EAS1SL1121
REMOVING THE NUMBER PLATE
1. Remove:• Bolt (number plate)
• Number plate “1”
TIP
• The projection “a” is inserted into the band of
the number plate. Pull the band off the projec-
tion before removal.
• Remove the clutch cable “2” from the cable
guide “b” on the number plate.
• The projection “c” on the lower bracket is in- serted into the number plate. Remove the
number plate by pulling it off the projection.
1
a
1
1
1