warning YAMAHA YZ450F 2005 Owner's Manual

5 - 2
CHAS
EC598100
REAR WHEEL
Extent of removal:
1 Rear wheel removal
2 Wheel bearing removal
3 Brake disc removal
Extent of removal Order Part name Q’ty Remarks
REAR WHEEL REMOVAL
WARNING
Support the machine securely so there is no
danger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
1 Nut (rear wheel axle) 1
2 Rear wheel axle 1
3 Chain puller 2
4 Rear wheel 1 Refer to “REMOVAL POINTS”.
5 Collar 2
6 Driven sprocket 1
7 Oil seal 2
8 Circlip 1
9 Bearing 2 Refer to “REMOVAL POINTS”.
10 Brake disc 1
2
31
3
FRONT WHEEL AND REAR WHEEL

5 - 4
CHASFRONT WHEEL AND REAR WHEEL
EC514200
Wheel axle
1. Measure:
Wheel axle bends
Out of specification → Replace.
Use the dial gauge 1.
NOTE:
The bending value is shown by one half of the
dial gauge reading.
WARNING
Do not attempt to straighten a bent axle.
Wheel axle bending limit:
0.5 mm (0.020 in)
EC594200
Brake disc
1. Measure:
Brake disc deflection (only rear brake
disc)
Use the dial gauge 1.
Out of specification → Inspect wheel
runout.
If wheel runout is in good condition,
replace the brake disc.
2. Measure:
Brake disc thickness a
Out of limit → Replace.
Disc deflection limit:
Standard
Rear—0.15 mm
(0.006 in)
Disc wear limit:
Standard
Front3.0 mm (0.12 in) 2.5 mm (0.10 in)
Rear4.0 mm (0.16 in) 3.5 mm (0.14 in)

5 - 10
CHASFRONT BRAKE AND REAR BRAKE
EC5A0000
FRONT BRAKE AND REAR BRAKE
EC5A8000
FRONT BRAKE
Extent of removal:
1 Brake hose removal
2 Caliper removal
3 Master cylinder removal
Extent of removal Order Part name Q’ty Remarks
FRONT BRAKE REMOVAL
WARNING
Support the machine securely so there is no
danger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Drain the brake fluid. Refer to “REMOVAL POINTS”.
1 Brake hose holder (protector) 2
2 Brake hose holder (caliper) 1
3 Union bolt 2
4 Brake hose 1
5 Pad pin plug 1 Remove when loosening the pad pin.
6 Pad pin 1 Loosen when disassembling the caliper.
7 Caliper 1
8Brake lever 1
9 Master cylinder bracket 1
10 Master cylinder 1
2
3
132

5 - 11
CHAS
EC5A8100
REAR BRAKE
Extent of removal:
1 Master cylinder removal
2 Brake hose removal
3 Caliper removal
Extent of removal Order Part name Q’ty Remarks
REAR BRAKE REMOVAL
WARNING
Support the machine securely so there is no
danger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Rear wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Drain the brake fluid. Refer to “REMOVAL POINTS”.
1 Brake pedal 1
2 Master cylinder 1
3 Brake hose holder 2
4 Union bolt 2
5 Brake hose 1
6 Pad pin plug 1 Remove when loosening the pad pin.
7 Pad pin 1 Loosen when disassembling the caliper.
8 Caliper 1
3
1
321
FRONT BRAKE AND REAR BRAKE

5 - 14
CHASFRONT BRAKE AND REAR BRAKE
EC5A3000
REMOVAL POINTS
Brake fluid
1. Remove:
[Front]
Master cylinder cap 1
[Rear]
Master cylinder cap 1
Protector
NOTE:
Do not remove the diaphragm.
ÈFront
ÉRear
2. Connect the transparent hose 2 to the
bleed screw 1 and place a suitable con-
tainer under its end.
ÈFront
ÉRear
È
É
3. Loosen the bleed screw and drain the
brake fluid while pulling the lever in or
pushing down on the pedal.
CAUTION:
Do not reuse the drained brake fluid.
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled
fluid immediately.
EC533301
Caliper piston
1. Remove:
Caliper piston
Use compressed air and proceed care-
fully.
WARNING
Cover piston with rag and use extreme
caution when expelling piston from cylin-
der.
Never attempt to pry out piston.
ÈFront
ÉRear
Caliper piston removal steps:
Insert a piece of rag into the caliper to lock
one caliper.
Carefully force the piston out of the caliper
cylinder with compressed air.
ÈÉ
È
É

5 - 15
CHASFRONT BRAKE AND REAR BRAKE
EC533402
Piston seal kit
1. Remove:
Dust seal 1
Piston seal 2
NOTE:
Remove the piston seals and dust seals by
pushing them with a finger.
CAUTION:
Never attempt to pry out piston seals and
dust seals.
WARNING
Replace the piston seals and dust seals
whenever a caliper is disassembled.
ÈFront
ÉRear
È
É
EC5A4000
INSPECTION
EC534112
Master cylinder
1. Inspect:
Master cylinder inner surface
a
Wear/scratches → Replace master cylin-
der assembly.
Stains → Clean.
WARNING
Use only new brake fluid.
ÈFront
ÉRear
2. Inspect:
Diaphragm 1
Crack/damage → Replace.
ÈFront
ÉRear
ÈÉ
ÈÉ
3. Inspect: (front brake only)
Reservoir float 1
Damage → Replace.

5 - 16
CHAS
4. Inspect:
Master cylinder piston 1
Master cylinder cup 2
Wear/damage/score marks → Replace
master cylinder kit.
ÈFront
ÉRear
ÈÉ
EC534214
Caliper
1. Inspect:
Caliper cylinder inner surface
a
Wear/score marks → Replace caliper
assembly.
ÈFront
ÉRear
ÈÉ
2. Inspect:
Caliper piston 1
Wear/score marks → Replace caliper pis-
ton assembly.
WARNING
Replace the piston seals and dust seals 2
whenever a caliper is disassembled.
EC534301
Brake hose
1. Inspect:
Brake hose 1
Crack/damage → Replace.
EC5A5000
ASSEMBLY AND INSTALLATION
WARNING
All internal parts should be cleaned in
new brake fluid only.
Internal parts should be lubricated with
brake fluid when installed.
Replace the piston seals and dust seals
whenever a caliper is disassembled.
FRONT BRAKE AND REAR BRAKE

5 - 17
CHAS
EC5A5800
Caliper piston
1. Clean:
Caliper
Piston seal
Dust seal
Caliper piston
Clean them with brake fluid.
2. Install:
Piston seal 1
Dust seal 2
WARNING
Always use new piston seals and dust
seals.
NOTE:
Fit the piston seals and dust seals onto the slot
on caliper correctly.
ÈFront
ÉRear
3. Install:
Caliper piston 1
NOTE:
Apply the brake fluid on the piston wall.
CAUTION:
Install the piston with its shallow
depressed side
a facing the caliper.
Never force to insert.
ÈFront
ÉRear
EC5A5700
Front caliper
1. Install:
Pad support 1
Brake pad 2
Pad pin 3
NOTE:
Install the brake pads with their projections
a into the caliper recesses
b.
Temporarily tighten the pad pin at this point.
È
New
New
É
È
É
FRONT BRAKE AND REAR BRAKE

5 - 19
CHASFRONT BRAKE AND REAR BRAKE
3. Install:
Caliper 1
Rear wheel 2
Refer to “FRONT WHEEL AND REAR
WHEEL” section.
4. Tighten:
Pad pin 3
5. Install:
Pad pin plug 4
Master cylinder kit
1. Clean:
Master cylinder
Master cylinder kit
Clean them with brake fluid.
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)
2. Install:
Master cylinder cup (primary) 1
Master cylinder cup (secondary) 2
To master cylinder piston 3.
NOTE:
Apply the brake fluid on the master cylinder
cup.
WARNING
After installing, cylinder cup should be
installed as shown direction. Wrong instal-
lation cause improper brake performance.
ÈFront
ÉRear
ÈÉ
ÈÉ
3. Install:
Spring 1
To master cylinder piston 2.
NOTE:
Install the spring at the smaller dia. side.
ÈFront
ÉRear
ÈÉ

5 - 21
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Brake lever 1
Bolt (brake lever) 2
Nut (brake lever) 3
NOTE:
Apply the lithium soap base grease on the
brake lever sliding surface, bolt and contacting
surface of the master cylinder piston.
Rear master cylinder
1. Install:
Copper washer 1
Brake hose 2
Union bolt 3
WARNING
Always use new copper washers.
CAUTION:
Install the brake hose so that its pipe por-
tion
a directs as shown and lightly
touches the projection
b on the master
cylinder.
T R..6 Nm (0.6 m · kg, 4.3 ft · lb)
T R..6 Nm (0.6 m · kg, 4.3 ft · lb)
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)
2. Install:
Master cylinder 1
Bolt (master cylinder) 2
3. Install:
Spring 1
Brake pedal 2
O-ring 3
Bolt (brake pedal) 4
Clip 5
NOTE:
Apply the lithium soap base grease on the bolt,
O-ring and brake pedal bracket.
T R..11 Nm (1.1 m · kg, 8.0 ft · lb)
New
T R..26 Nm (2.6 m · kg, 19 ft · lb)