2014 YAMAHA YZ450F brake

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
4-29
ASSEMBLING THE REAR BRAKE MASTER
CYLINDER
EWA13520
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
WARNING
Apply brake fluid to the cylinder cups and
install them as shown. Wrong orientation in
installation causes poor braking perfor
-
mance.
3. Install:
• Spring “1”
Install to the brake master cylinder piston
“2.”
TIP
Install the spring with a smaller inside diameter
to the brake master cylinder piston.
4. Install:
• Master cylinder kit “1”
• Push rod “2”
• Circlip “3”
• Dust boot “4”
TIP
• Before installation, apply brake fluid to the
brake master cylinder kit.
• Before installation, apply silicone grease to
the push rod end.
• Use circlip pliers to install the circlip.
EAS1SL1160INSTALLING THE REAR BRAKE MASTER
CYLINDER
1. Install:
• Copper washers
• Brake hose
• Union bolt
EWA13530
WARNING
Proper brake hose routing is essential to in-
sure safe vehicle operation.Refer to“CABLE
ROUTING DIAGRAM” on page 2-33.
ECA1DX1008
NOTICE
Make sure that the pipe portion of the brake
hose touches the projection “a” on the
brake caliper.
Recommended brake fluid
DOT 4
New
New
2
3
1
2
3
1Brake hose union bolt
30 Nm (3.0 m·kgf, 22 ft·lbf)
12
New
New
13
4
2NewNew
New
T R..

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

HANDLEBAR
4-31
EAS1SL1161
HANDLEBAR
Removing the handlber
OrderPart name Q’tyRemarks
Number plate Remove the band only.
1 Clutch cable 1 Disconnect.
2 Clutch lever holder 1
3 Engine stop switch 1
4 Brake master cylinder 1
5 Throttle cable cap 1
6 Throttle cable (pull) 1 Disconnect.
7 Throttle cable (return) 1 Disconnect.
8 Right grip 1
9 Tube guide 1
10 Collars 1
11 Left grip 1
12 Handlebar upper holder 2
13 Handlebar 1
14 Handlebar lower holder 2
15 Damper 4

HANDLEBAR
4-36
10.Install:
• Rubber cover “1”
• Cover (throttle cable housings) “2”
11.Install:
• Front brake master cylinder assembly “1”
• Front brake master cylinder holder “2”
• Bolt (brake master cylinder holder) “3”
TIP
• Install the brake master cylinder holder with
the “UP” mark facing up.
• Install in order for the top of the front brake
master cylinder assembly to be level.
• First, tighten the upper bolt, then the lower
bolt.
12.Install:
• Clutch cable “1”
TIP
Before installation, apply the lithium-soap-
based grease to the clutch cable end.
13.Adjust:
• Clutch lever free play
Refer to “ADJUSTING THE CLUTCH LE-
VER FREE PLAY” on page 3-10.
14.Adjust:
• Throttle grip free play
Refer to “ADJUSTING THE THROTTLE
GRIP FREE PLAY” on page 3-11.
Front brake master cylinder hold-
er bolt
9 Nm (0.9 m·kgf, 6.5 ft·lbf)
T R..
Clutch lever free play
7.0-12.0 mm (0.28-0.47 in)
Throttle grip free play
3.0-5.0 mm (0.12-0.20 in)
1LS

FRONT FORK
4-37
EAS1SL1165
FRONT FORK
Removing the front fork legs
OrderPart nameQ’tyRemarks
Use a suitable stand to raise the front wheel
off the ground.
Front wheelRefer to “FRONT WHEEL” on page 4-3.
Front brake caliperRefer to “FRONT BRAKE” on page 4-11.
Number plateRefer to “GENERAL CHASSIS” on page 4-1.
1Protector1
2Upper bracket pinch bolts2Loosen.
3Damper assembly1Loosen.
4Lower bracket pinch bolts2Loosen.
5Front fork leg1
For installation, reverse the removal proce-dure.
3
2
4
5
1
T.R.21 Nm (2.1 mlbf) kgf, 15 ft
T.R.9 Nm (0.9 mlbf) kgf, 6.5 ft
T.R.5 Nm (0.5 mlbf) kgf, 3.6 ft
T.R.5 Nm (0.5 mlbf) kgf, 3.6 ft

SWINGARM
4-60
EAS1SL1184
SWINGARM
Removing the swingarm
OrderPart nameQ’tyRemarks
Use a suitable stand to raise the front wheel
off the ground.
Brake hose holderRefer to “REAR BRAKE” on page 4-21.
Rear brake caliperRefer to “REAR BRAKE” on page 4-21.
Bolt (brake pedal)
Drive chain
1Collars2
2Oil seals2
3Thrust bearing2
4Bushing2
5Oil seals2
6Bearing4
For installation, reverse the removal proce-dure.
1
2
3
6
4
6
4
1
3
6
2
5
T.R.70 Nm (7.0 mlbf) kgf, 51 ft
T.R.4.0 Nm (0.40 mlbf) kgf, 2.9 ft

5
ENGINE
ENGINE REMOVAL......................................................................................... 5-1
REMOVING THE SILENCER ..................................................................... 5-6
REMOVING THE EXHAUST PIPE 2.......................................................... 5-6
REMOVING THE DRIVE SPROCKET ....................................................... 5-6
REMOVING THE ENGINE ......................................................................... 5-7
CHECKING THE SILENCER AND EXHAUST PIPE.................................. 5-7
CHANGING THE SILENCER FIBER ......................................................... 5-7
INSTALLING THE ENGINE........................................................................ 5-8
INSTALLING THE BRAKE PEDAL ............................................................ 5-9
INSTALLING THE DRIVE SPROCKET...................................................... 5-9
INSTALLING THE EXHAUST PIPE AND MUFFLER............................... 5-10
CAMSHAFT.................................................................................................... 5-11
REMOVING THE CAMSHAFT ................................................................. 5-13
CHECKING THE CAMSHAFT.................................................................. 5-14
CHECKING THE TIMING CHAIN AND CAMSHAFT SPROCKET .......... 5-15
CHECKING THE TIMING CHAIN TENSIONERS .................................... 5-15
CHECKING THE DECOMPRESSION SYSTEM...................................... 5-16
INSTALLING THE CAMSHAFTS ............................................................. 5-16
CYLINDER HEAD........................................................................................... 5-19
REMOVING THE CYLINDER HEAD........................................................ 5-21
CHECKING THE TIMING CHAIN GUIDE (INTAKE SIDE) ...................... 5-21
CHECKING THE CYLINDER HEAD ........................................................ 5-21
INSTALLING THE CYLINDER HEAD ...................................................... 5-22
VALVES AND VALVE SPRINGS................................................................... 5-24
REMOVING THE VALVES ....................................................................... 5-25
CHECKING THE VALVES AND VALVE GUIDES ................................... 5-26
CHECKING THE VALVE SEATS ............................................................. 5-27
CHECKING THE VALVE SPRINGS......................................................... 5-29
CHECKING THE VALVE LIFTERS .......................................................... 5-29
INSTALLING THE VALVES ..................................................................... 5-30
CYLINDER AND PISTON............................................................................... 5-32
REMOVING THE PISTON ....................................................................... 5-33
CHECKING THE CYLINDER AND PISTON ............................................ 5-33
CHECKING THE PISTON RINGS............................................................ 5-34
CHECKING THE PISTON PIN ................................................................. 5-35
INSTALLING THE PISTON AND CYLINDER .......................................... 5-35