brake YAMAHA YZ250F 2003 Owner's Manual

3 - 30
INSP
ADJREAR BRAKE PAD INSULATOR INSPECTION/
BRAKE FLUID LEVEL INSPECTION
3. Inspect:
Brake fluid level
Refer to “BRAKE FLUID LEVEL
INSPECTION” section.
4. Check:
Brake pedal operation
A softy or spongy feeling → Bleed
brake system.
Refer to “BRAKE SYSTEM AIR
BLEEDING” section.
EC36b000
REAR BRAKE PAD INSULATOR
INSPECTION
1. Remove:
Brake pad
Refer to “REAR BRAKE PAD INSPEC-
TION AND REPLACEMENT” section.
2. Inspect:
Rear brake pad insulator 1
Damage → Replace.
BRAKE FLUID LEVEL INSPECTION
1. Place the brake master cylinder so that
its top is in a horizontal position.
2. Inspect:
Brake fluid level
Fluid at lower level → Fill up.
aLower level
ÅFront
ıRear
WARNING
Use only designated quality brake fluid to
avoid poor brake performance.
Refill with same type and brand of brake
fluid; mixing fluids could result in poor
brake performance.
Be sure that water or other contaminants
do not enter master cylinder when refill-
ing.
Clean up spilled fluid immediately to
avoid erosion of painted surfaces or plas-
tic parts.
Recommended brake fluid:
DOT #4
Å
ı

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INSP
ADJ
FRONT FORK INSPECTION
3. Adjust:
Drive chain slack
Drive chain slack adjustment steps:
Loosen the axle nut 1 and locknuts 2.
Adjust the drive chain slack by turning the
adjusters 3.
To tighten → Turn the adjuster 3 coun-
terclockwise.
To loosen → Turn the adjuster 3 clock-
wise and push wheel forward.
Turn each adjuster exactly the same
amount to maintain correct axle alignment.
(There are marks a on each side of the
drive chain puller alignment.)
NOTE:
Turn the adjuster so that the drive chain is in
line with the sprocket, as viewed from the
rear.
CAUTION:
Too small drive chain slack will overload
the engine and other vital parts; keep the
slack within the specified limits.
Tighten the axle nut while pushing down
the drive chain.
T R..
Axle nut:
125 Nm (12.5 m • kg, 90 ft • lb)
Tighten the locknuts.
T R..
Locknut:
16 Nm (1.6 m • kg, 11 ft • lb)
EC36C000
FRONT FORK INSPECTION
1. Inspect:
Front fork smooth action
Operate the front brake and stroke the
front fork.
Unsmooth action/oil leakage → Repair
or replace.

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INSP
ADJ
LUBRICATION
LUBRICATION
To ensure smooth operation of all compo-
nents, lubricate your machine during setup,
after break-in, and after every race.
1All control cable
2Clutch lever pivot
3Shift pedal pivot
4Footrest pivot
5Throttle-to-handlebar contact
6Drive chain
7Tube guide cable winding portion
8Throttle cable end
9Clutch cable end
0Hot starter cable endÅUse Yamaha cable lube or equivalent on these
areas.
ıUse SAE 10W-30 motor oil or suitable chain
lubricants.
ÇLubricate the following areas with high quality,
lightweight lithium-soap base grease.
CAUTION:
Wipe off any excess grease, and avoid get-
ting grease on the brake discs.
AAA
AAB
CC

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ENGCLUTCH
EC4A0000
CLUTCH
Extent of removal:1 Push rod 1, 2 and push lever shaft removal2 Push pod 1 disassembly
3 Friction plate and clutch plate removal4 Primary driven gear removal
Extent of removal Order Part name Q’ty Remarks
CLUTCH REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Brake pedal Refer to “ENGINE REMOVAL” section.
Clutch cable Disconnect at engine side.
1 Clutch cover 1
2 Clutch spring 5
3 Pressure plate 1
4 Push rod 1 1
5 Circlip 1
6 Washer 1
7 Bearing 1
8 Ball 1
9Push rod 2
1
4
1
12
3

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ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
Extent of removal:1 Oil filter element removal2 Water pump removal
3 Right crankcase cover removal
Extent of removal Order Part name Q’ty Remarks
OIL FILTER ELEMENT, WATER
PUMP AND RIGHT CRANK-
CASE COVER REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Drain the coolant. Refer to “COOLANT REPLACEMENT”
section in the CHAPTER 3.
Radiator hose 3 Disconnect at water pump side.
Exhaust pipe Refer to “EXHAUST PIPE AND
SILENCER” section.
Brake pedal Refer to “ENGINE REMOVAL” section.
Right engine guard
1 Oil filter element cover 1
2 Oil filter element 1
13

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ENGENGINE REMOVAL
Extent of removal:1 Engine removal
Extent of removal Order Part name Q’ty Remarks
Ignition coil
Disconnect the CDI magneto lead.
Right engine guard
1 Lower engine guard 1
2 Neutral switch 1
3 Bolt (oil hose) 2
4 Drive chain sprocket cover 1
5 Nut (drive sprocket) 1
Refer to “REMOVAL POINTS”. 6 Lock washer 1
7 Drive sprocket 1
8 Clip 1
9 Bolt (brake pedal) 1
10 Brake pedal 1
11 Upper engine bracket 2
12 Lower engine bracket 2
13 Engine mounting bolt 3
14 Pivot shaft 1
Refer to “REMOVAL POINTS”.
15 Engine 1
1

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ENGENGINE REMOVAL
EC4M3000
REMOVAL POINTS
EC4F3100
Drive sprocket
1. Remove:
Nut (drive sprocket) 1
Lock washer 2
NOTE:
Straighten the lock washer tab.
Loosen the nut while applying the rear brake.
2. Remove:
Drive sprocket 1
Drive chain 2
NOTE:
Remove the drive sprocket together with the
drive chain.
EC4M3301
Engine removal
1. Remove:
Pivot shaft 1
NOTE:
If the pivot shaft is pulled all the way out, the
swingarm will come loose. If possible, insert a
shaft of similar diameter into the other side of
the swingarm to support it.
2. Remove:
Engine 1
From right side.
NOTE:
Make sure that the couplers, hoses and cables
are disconnected.
1

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ENGENGINE REMOVAL
EC4M5000
ASSEMBLY AND INSTALLATION
Engine installation
1. Install:
Engine 1
Install the engine from right side.
Pivot shaft 2
Engine mounting bolt (lower) 3
Lower engine bracket 4
Bolt (engine bracket) 5
Engine mounting bolt (front) 6
Upper engine bracket 7
Engine mounting bolt (upper) 8
Lower engine guard 9
Bolt (lower engine guard) 0
NOTE:
Apply the molybdenum disulfide grease on the
pivot shaft.
EC4M5211
Brake pedal
1. 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-rings and brake pedal bracket.
Install the clip with its stopper portion a fac-
ing inward.
T R..85 Nm (8.5 m · kg, 61 ft · lb)
T R..69 Nm (6.9 m · kg, 50 ft · lb)
T R..34 Nm (3.4 m · kg, 24 ft · lb)
T R..69 Nm (6.9 m · kg, 50 ft · lb)
T R..55 Nm (5.5 m · kg, 40 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..26 Nm (2.6 m · kg, 19 ft · lb)
Drive sprocket
1. Install:
Drive sprocket 1
Drive chain 2
NOTE:
Install the drive sprocket together with the
drive chain.

4 - 86
ENGENGINE REMOVAL
2. Install:
Lock washer 1
Nut (drive sprocket) 2
NOTE:
Tighten the nut while applying the rear brake.
T R..75 Nm (7.5 m · kg, 54 ft · lb)
3. Bend the lock washer tab to lock the nut.
4. Install:
Drive chain sprocket guide 1
Drive chain sprocket cover 2
Screw (drive chain sprocket cover) 3
T R..8 Nm (0.8 m · kg, 5.8 ft · lb)
Oil hose and neutral switch
1. Install:
O-ring 1
Dowel pin 2
Oil hose 3
Bolt (oil hose) 4
NOTE:
Apply the lithium soap base grease on the O-
ring.
2. Install:
Spring 1
Pin 2
O-ring 3
Neutral switch 4
Screw (neutral switch) 5
NOTE:
Apply the lithium soap base grease on the O-
ring.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)

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