brake YAMAHA YZ250F 2001 Manuale duso (in Italian)

5 - 1
CHAS

EC500000
CHASSIS
EC590000
FRONT WHEEL AND REAR WHEEL
EC598000
FRONT WHEEL
FRONT WHEEL AND REAR WHEEL
Extent of removal:
1
Front wheel removal
2
Wheel bearing removal
3
Brake disc removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removal
FRONT 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 Brake hose cover 1
2 Bolt (brake hose holder) 2 Only loosening.
3 Bolt (axle holder) 4 Only loosening.
4 Nut (front wheel axle) 1
5 Front wheel axle 1
6 Front wheel 1
7 Collar 2
8 Oil seal 2
9 Bearing 2 Refer to “REMOVAL POINTS”.
10Brake disc
1
2
31
3





5

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
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 Drive chain puller 2
4 Rear wheel 1 Refer to “REMOVAL POINTS”.
5 Collar 2
6 Rear wheel sprocket 1
7 Oil seal 2
8 Circlip 1
9 Bearing 2 Refer to “REMOVAL POINTS”.
10Brake disc
1
2
31
3

FRONT WHEEL AND REAR WHEEL

5 - 4
CHAS

FRONT WHEEL AND REAR WHEEL
EC514200
Wheel axle
1. Measure:
l
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:
l
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:
l
Brake disc thickness
a

Out of limit
®
Replace.
Brake disc deflection limit:
Rear:
: 0.15 mm (0.006 in)
Brake disc thickness:
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 - 5
CHAS

FRONT WHEEL AND REAR WHEEL
EC595000
ASSEMBLY AND INSTALLATION
Front wheel
1. Install:
l
Bearing (left)
1

l
Spacer
2

l
Bearing (right)
3

l
Oil seal
4

NOTE:

l
Apply the lithium soap base grease on the
bearing and oil seal lip when installing.
l
Use a socket that matches the outside diam-
eter of the race of the bearing.
l
Left side of bearing shall be installed first.
l
Install the oil seal with its manufacture’s
marks or numbers facing outward.
ACHTUNG:CAUTION:
Do not strike the inner race of the bearing.
Contact should be made only with the outer
race.
2. Install:
lBrake disc 1
lBolt (brake disc) 2
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
3. Install:
lCollar 1
NOTE:
lApply the lithium soap base grease on the oil
seal lip.
lInstall the collars with their projections a
facing the wheel.
4. Install:
lWheel
NOTE:
Install the brake disc 1 between the brake
pads 2 correctly.

5 - 6
CHASFRONT WHEEL AND REAR WHEEL
5. Install:
lWheel axle 1
NOTE:
Apply the lithium soap base grease on the
wheel axle.
6. Install:
lNut (wheel axle) 1
T R..105 Nm (10.5 m · kg, 75 ft · lb)
7. Tighten:
lBolt (axle holder) 1
NOTE:
Before tightening the bolt, fit the wheel axle to
the axle holder by stroking the front fork sev-
eral times with the front brake applied.
8. Install:
lBrake hose 1
To brake hose holder 2.
NOTE:
Before tightening the bolt (brake hose holder),
pass the brake hose in front of the axle boss
a, then fit it into the hose groove b so that the
brake hose does not contact the nut (wheel
axle).
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

5 - 7
CHASFRONT WHEEL AND REAR WHEEL
9. Install:
lBrake hose cover 1
lWasher 2
lBolt [brake hose cover (M8)] 3
lBolt [brake hose cover (M6)] 4
T R..16 Nm (1.6 m · kg, 11 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
Rear wheel
1. Install:
lBearing (right) 1
lCirclip 2
lSpacer 3
lBearing (left) 4
lOil seal 5
NOTE:
lApply the lithium soap base grease on the
bearing and oil seal lip when installing.
lInstall the bearing with seal facing outward.
lUse a socket that matches the outside diam-
eter of the race of the bearing.
lRight side of bearing shall be installed first.
lInstall the oil seal with its manufacture’s
marks or numbers facing outward.
ACHTUNG:CAUTION:
Do not strike the inner race of the bearing.
Contact should be made only with the outer
race.
2. Install:
lBrake disc 1
lBolt (brake disc) 2
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..14 Nm (1.4 m · kg, 10 ft · lb)

5 - 8
CHAS
3. Install:
lRear wheel sprocket 1
lBolt (rear wheel sprocket) 2
lWasher (rear wheel sprocket) 3
lNut (rear wheel sprocket) 4
NOTE:
Tighten the nuts in stage, using a crisscross
pattern.
T R..42 Nm (4.2 m · kg, 30 ft · lb)
FRONT WHEEL AND REAR WHEEL
4. Install:
lCollar 1
NOTE:
Apply the lithium soap base grease on the oil
seal lip.
5. Install:
lWheel
NOTE:
Install the brake disc 1 between the brake
pads 2 correctly.
6. Install:
lDrive chain 1
NOTE:
Push the wheel 2 forward and install the drive
chain.
7. Install:
lLeft drive chain puller 1
lWheel axle 2
NOTE:
lInstall the left drive chain puller, and insert
the wheel axle from left side.
lApply the lithium soap base grease on the
wheel axle.

5 - 10
CHASFRONT BRAKE AND REAR BRAKE
EC5A0000
FRONT BRAKE AND REAR BRAKE
EC5A8000
FRONT BRAKE
Extent of removal:1 Brake hose removal2 Brake caliper removal
3 Brake 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 Brake 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 Brake caliper 1
9 Brake lever 1
10 Brake master cylinder bracket 1
11 Brake master cylinder 1
2
3
1
3
2

5 - 11
CHAS
EC5A8100
REAR BRAKE
Extent of removal:1 Brake caliper removal2 Brake hose removal
3 Brake 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 Brake 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
10Brake master cylinder
1
3
1
321
FRONT BRAKE AND REAR BRAKE

5 - 12
CHAS
BRAKE CALIPER DISASSEMBLY
Front
õRear
Extent of removal:1 Front brake caliper disassembly2 Rear brake caliper disassembly
Extent of removal Order Part name Q’ty Remarks
BRAKE CALIPER DISASSEM-
BLYAB
1 Pad pin 1 1
2 Brake pad 2 2
3 Pad support 1 1
4 Brake caliper piston 2 1 Refer to “REMOVAL POINTS”.
5 Dust seal 2 1
Refer to “REMOVAL POINTS”.
6 Piston seal 2 1
12
FRONT BRAKE AND REAR BRAKE