warning YAMAHA YZ426F 2001 Owner's Manual

5 - 2
CHAS

EC598100
REAR WHEEL
Extent of removal:
1
Rear wheel removal
2
Wheel bearing removal
3
Break disc removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removal
REAR WHEEL REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING

Support the machine securely so there is no
danger of it falling over.
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”.
10Brake disk
1
2
31
3

FRONT WHEEL AND REAR WHEEL

5 - 4
CHASFRONT WHEEL AND REAR WHEEL
EC514200
Wheel axle
1. Measure:
lWheel 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:
lBrake 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:
lBrake disc thickness a
Out of limit ® Replace.
Disc deflection limit:
Standard
Rear —0.15 mm
(0.006 in)
Disc wear limit:
Standard
Front 3.0 mm (0.12 in) 2.5 mm (0.10 in)
Rear 4.0 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 removal2 Caliper removal
3 Master cylinder removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalFRONT BRAKE REMOVAL
Hold the machine by placing the
suitable stand under the engine.
Drain the brake fluid.
WARNING
Support the machine securely so there is nodanger of it falling over.
Refer to “REMOVAL POINTS”.
1 Hose cover 1
2 Brake hose holder 1
3 Bolt (brake hose holder) 2 Only loosening.
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
9 Brake lever 1
10 Master cylinder bracket 1
11 Master cylinder 1
2
3
1
3
2

5 - 11
CHAS
EC5A8100
REAR BRAKE
Extent of removal:1 Caliper removal2 Brake hose removal
3 Master cylinder removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalREAR BRAKE REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
Rear wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Drain the brake fluid. Refer to “REMOVAL POINTS”.
1 Pad pin plug 1 Remove when loosening the pad pin.
2 Pad pin 1 Loosen when disassembling the caliper.
3 Caliper 1
4 Brake hose holder 2
5 Union bolt 2
6 Brake hose 1
7 Brake pedal 1
8 Reservoir tank 1
9 Reservoir hose 1
10 Master cylinder 1
3
1
321
FRONT BRAKE AND REAR BRAKE

5 - 14
CHASFRONT BRAKE AND REAR BRAKE
EC5A3000
REMOVAL POINTS
Brake fluid
1. Remove:
[Front]
lMaster cylinder cap 1
[Rear]
lMaster cylinder guard 1
lReservoir tank cap 2
NOTE:
Do not remove the diaphragm.
Front
õRear
2. Connect the transparent hose 2 to the
bleed screw 1 and place a suitable con-
tainer under its end.
Front
õRear

õ
3. Loosen the bleed screw and drain the
brake fluid while pulling the lever in or
pushing down on the pedal.
ACHTUNG:CAUTION:
lDo not reuse the drained brake fluid.
lBrake fluid may erode painted surfaces or
plastic parts. Always clean up spilled
fluid immediately.
EC533301
Caliper piston
1. Remove:
lCaliper piston
Use compressed air and proceed care-
fully.
WARNING
lCover piston with rag and use extreme
caution when expelling piston from cylin-
der.
lNever attempt to pry out piston.
Front
õRear
Caliper piston removal steps:
lInsert a piece of rag into the caliper to lock
one caliper.
lCarefully force the piston out of the caliper
cylinder with compressed air.
õ


õ

5 - 15
CHASFRONT BRAKE AND REAR BRAKE
EC533402
Piston seal kit
1. Remove:
lDust seal 1
lPiston seal 2
NOTE:
Remove the piston seals and dust seals by
pushing them with a finger.
ACHTUNG:CAUTION:
Never attempt to pry out piston seals and
dust seals.
WARNING
Replace the piston seals and dust seals
whenever a caliper is disassembled.
Front
õRear

õ
EC5A4000
INSPECTION
EC534112
Master cylinder
1. Inspect:
lMaster cylinder inner surface a
Wear/scratches ® Replace master cyl-
inder assembly.
Stains ® Clean.
WARNING
Use only new brake fluid.
Front
õRear
2. Inspect:
lDiaphragm 1
Crack/damage ® Replace.
Front
õRear
õ

õ

3. Inspect:
lMaster cylinder piston 1
lMaster cylinder cup 2
Wear/damage/score marks ® Replace
master cylinder kit.
Front
õRear
õ

5 - 16
CHAS
EC534214
Caliper
1. Inspect:
lCaliper cylinder inner surface a
Wear/score marks ® Replace caliper
assembly.
Front
õRear
õ
2. Inspect:
lCaliper piston 1
Wear/score marks ® Replace caliper
piston assembly.
WARNING
Replace the piston seals and dust seals 2
whenever a caliper is disassembled.
EC534301
Brake hose
1. Inspect:
lBrake hose 1
Crack/damage ® Replace.
EC5A5000
ASSEMBLY AND INSTALLATION
WARNING
lAll internal parts should be cleaned in
new brake fluid only.
lInternal parts should be lubricated with
brake fluid when installed.
lReplace the piston seals and dust seals
whenever a caliper is disassembled.
EC5A5800
Caliper piston
1. Clean:
lCaliper
lPiston seal
lDust seal
lCaliper piston
Clean them with brake fluid.
FRONT BRAKE AND REAR BRAKE

5 - 17
CHAS
2. Install:
lPiston seal 1
lDust 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.
Front
õRear

New
New
õ
3. Install:
lCaliper piston 1
NOTE:
Apply the brake fluid on the piston wall.
ACHTUNG:CAUTION:
lFor the front caliper, install the piston
with its depressed side a facing the cali-
per. For the rear caliper, install the piston
with its shallow depressed side b facing
the caliper.
lNever force to insert.
Front
õRear
EC5A5700
Front caliper
1. Install:
lPad support 1
lBrake pad 2
lPad pin 3
NOTE:
lInstall the brake pads with their projections
a into the caliper recesses b.
lTemporarily tighten the pad pin at this point.

õ
FRONT BRAKE AND REAR BRAKE

5 - 18
CHAS

FRONT BRAKE AND REAR BRAKE
2. Install:
l
Copper washer
1
l
Union bolt
2

WARNING

Always use new copper washers.
ACHTUNG:CAUTION:

Install the brake hose so that its pipe por-
tion
a
directs as show and lightly touches
the projection
b
on the caliper.
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)

3. Install:
l
Brake hose holder
1

l
Caliper
2

l
Bolt (caliper)
3

NOTE:

Fit the brake hose holder cut
a over the pro-
jection b on the front fork and clamp the brake
hose.
4. Tighten:
lPad pin 4
5. Install:
lPad pin plug 5
EC5A5100
Rear caliper
1. Install:
lPad support 1
lBrake pad 2
lPad pin 3
NOTE:
lInstall the brake pads with their projections
a into the caliper recesses b.
lTemporarily tighten the pad pin at this point.
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)

5 - 19
CHAS

FRONT BRAKE AND REAR BRAKE
2. Install:
l
Disc cover
1

l
Bolt (disc cover)
2

T R..7 Nm (0.7 m · kg, 5.1 ft · lb)

3. Install:
l
Copper washer
1

l
Brake hose
2

l
Union bolt
3

WARNING

Always use new copper washers.
ACHTUNG:CAUTION:

Install the brake hose to the caliper with the
paint
a
on the pipe facing the caliper and
with the pipe contacting the caliper projec-
tion
b
.
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)

4. Install:
l
Caliper
1

l
Rear wheel
2

Refer to “FRONT WHEEL AND REAR
WHEEL” section.
5. Tighten:
l
Pad pin
3

6. Install:
l
Pad pin plug
4

T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)