2002 YAMAHA YZ250LC ECU

34 Nm (3.4 m•kg, 24 ft•lb)
4-60
ENGINE REMOVALENG
Extent of removal Order Part name Q’ty Remarks
ENGINE REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
Seat and fuel tankRefer to “SEAT, FUEL TANK AND
SIDE COVERS” section.
Carburetor and carburetor jointRefer to “CARBURETOR AND REED
VALVE” section.
Exhaust pipe and silencer Refer to “EXHAUST PIPE AND
Exhaust pipe stay (rear) SILENCER” section.
Clutch cable Disconnect at engine side.
Radiator Refer to “RADIATOR” section.
Spark plug
Disconnect the CDI magneto lead.
CDI unit
Reservoir tank (rear brake) Refer to “FRONT BRAKE AND REAR
BRAKE” section in the CHAPTER 5.
EC4M0000
ENGINE REMOVAL
w
Support the machine securely so there is no dan-
ger of it falling over.



26 Nm (2.6 m•kg, 19 ft•lb)
69 Nm (6.9 m•kg, 50 ft•lb)
69 Nm (6.9 m•kg, 50 ft•lb)
75 Nm (7.5 m•kg, 54 ft•lb)
8 Nm (0.8 m•kg, 5.8 ft•lb)
85 Nm (8.5 m•kg, 61 ft•lb)
5NX-9-30-4C 6/5/01 4:25 PM Page 22

5-1
CHASFRONT WHEEL AND REAR WHEEL
Extent of removal Order Part name Q’ty Remarks
FRONT WHEEL REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
1 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”.
10 Brake disk 1
EC500000
CHASSISEC590000
FRONT WHEEL AND REAR WHEELEC598000
FRONT WHEEL
2
13
3
Extent of removal:1Front wheel removal2Wheel bearing removal3Brake disc removal
w
Support the machine securely so there is no dan-
ger of it falling over.
5
23 Nm (2.3 m•kg, 17 ft•lb)
23 Nm (2.3 m•kg, 17 ft•lb)
105 Nm (10.5 m•kg, 75 ft•lb)
16 Nm (1.6 m•kg, 11 ft•lb)
7 Nm (0.7 m•kg, 5.1 ft•lb)12 Nm (1.2 m•kg, 8.7 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
5NX-9-30-5A 6/7/01 2:00 PM Page 2

5-2
CHASFRONT WHEEL AND REAR WHEEL
EC598100
REAR WHEEL
Extent of removal:1Rear wheel removal2Wheel bearing removal3Brake disc removal
Extent of removal Order Part name Q’ty Remarks
REAR WHEEL REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable 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 disk 1
2
13
3
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Support the machine securely so there is no dan-
ger of it falling over.
125 Nm (12.5 m•kg, 90 ft•lb)
14 Nm (1.4 m•kg, 10 ft•lb)
42 Nm (4.2 m•kg, 30 ft•lb)
5NX-9-30-5A 6/7/01 2:00 PM Page 4

5-10
CHASFRONT BRAKE AND REAR BRAKE
Extent of removal Order Part name Q’ty Remarks
FRONT BRAKE REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
Drain the brake fluid. 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 1Loosen when disassembling the caliper.
8 Caliper 1
9 Brake lever 1
10 Master cylinder bracket 1
11 Master cylinder 1
EC5A0000
FRONT BRAKE AND REAR BRAKEEC5A8000
FRONT BRAKE
Extent of removal:1Brake hose removal2Caliper removal3Master cyilinder removal
w
Support the machine securely so there is no dan-
ger of it falling over.
2
1
3
3
2
9 Nm (0.9 m•kg, 6.5 ft•lb)
6 Nm (0.6 m•kg, 4.3 ft•lb)
6 Nm (0.6 m•kg, 4.3 ft•lb)
6 Nm (0.6 m•kg, 4.3 ft•lb)
3 Nm (0.3 m•kg, 2.2 ft•lb)
18 Nm (1.8 m•kg, 13 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
7 Nm (0.7 m•kg, 5.1 ft•lb)16 Nm (1.6 m•kg, 11 ft•lb)
23 Nm (2.3 m•kg, 17 ft•lb)
30 Nm (3.0 m•kg, 22 ft•lb)
30 Nm (3.0 m•kg, 22 ft•lb)
5NX-9-30-5A 6/7/01 2:00 PM Page 20

5-11
CHASFRONT BRAKE AND REAR BRAKE
EC5A8100
REAR BRAKE
Extent of removal Order Part name Q’ty Remarks
REAR BRAKE REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
Rear wheel Refer to “FRONT WHEEL AND
REAR WHEEL” section.
Drain the brake fluid. Refer to “REMOVAL POINTS”.
1 Pad pin pulg 1
Remove when loosening the pad pin.
2 Pad pin 1Loosen 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
Extent of removal:1Caliper removal2Brake hose removal3Master cylinder removal
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Support the machine securely so there is no dan-
ger of it falling over.
2
1
3
31
1 Nm (0.1 m•kg, 0.7 ft•lb)
30 Nm (3.0 m•kg, 22 ft•lb)
3 Nm (0.3 m•kg, 2.2 ft•lb)
18 Nm (1.8 m•kg, 13 ft•lb)
6 Nm (0.6 m•kg, 4.3 ft•lb)
26 Nm (2.6 m•kg, 19 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
7 Nm (0.7 m•kg, 5.1 ft•lb)
5NX-9-30-5A 6/7/01 2:00 PM Page 22

5-27
CHASFRONT FORK
Extent of removal Order Part name Q’ty Remarks
FRONT FORK REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
Front wheel Refer to “FRONT WHEEL AND
REAR WHEEL”section.
Front caliper Refer to “FRONT BRAKE AND
REAR BRAKE”section.
Number plate
1 Protector 1
2 Brake hose holder 2
3 Pinch bolt (handle crown) 2 Only loosening.
4 Cap bolt 1
Loosen when disassembling the front fork.
5 Pinch bolt (under bracket) 2 Only loosening.
6 Front fork 1
1
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Support the machine securely so there is no dan-
ger of it falling over.
Extent of removal:1Front fork removal
4 Nm (0.4 m•kg, 2.9 ft•lb)
20 Nm (2.0 m•kg, 14 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
23 Nm (2.3 m•kg, 17 ft•lb)
EC550000
FRONT FORK
5NX-9-30-5B 6/7/01 2:04 PM Page 2

5-47
CHASSTEERING
Extent of removal Order Part name Q’ty Remarks
STEERING REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
Number plate
Handlebar Refer to “HANDLEBAR” section.
Cable guide
Front fender
1 Steering shaft nut 1
2 Front fork 2 Refer to “FRONT FORK” section.
3 Handle crown 1
4 Ring nut 1 Use special tool.
Refer to “REMOVAL POINTS”.
5 Under bracket 1
6 Ball race cover 1
7 Bearing (upper) 1
8 Bearing (lower) 1 Refer to “REMOVAL POINTS”.
9 Ball race 2 Refer to “REMOVAL POINTS”. Extent of removal:1Under bracket removal 2Bearing removal
2
1
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Support the machine securely so there is no dan-
ger of it falling over.
23 Nm (2.3 m•kg, 17 ft•lb)
145 Nm (14.5 m•kg, 105 ft•lb)
9Tighten ring nut.
38 Nm (3.8 m•kg, 27 ft•lb)
9Loosen it one turn.
9Retighten it.
7 Nm (0.7 m•kg, 5.1 ft•lb)
TIGHTENING STEPS:
20 Nm (2.0 m•kg, 14 ft•lb)
EC560000
STEERING
5NX-9-30-5C 6/5/01 4:37 PM Page 16

5-52
CHASSWINGARM
Extent of removal Order Part name Q’ty Remarks
SWINGARM REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
Brake hose holderRefer to “FRONT BRAKE AND
Rear caliperREAR BRAKE”section.
Bolt (brake pedal) Shift the brake pedal backward.
Drive chain
1 Chain support 1
2 Chain tensioner (lower) 1
3
Bolt (rear shock absorber-relay arm)1 Hold the swingarm.
4 Bolt (connecting rod) 1
5 Pivot shaft 1
6 Swingarm 1
EC570000
SWINGARM
Extent of removal:1Swingarm removal
1
w
Support the machine securely so there is no dan-
ger of it falling over.



53 Nm (5.3 m•kg, 38 ft•lb)
80 Nm (8.0 m•kg, 58 ft•lb)
19 Nm (1.9 m•kg, 13 ft•lb)
7 Nm (0.7 m•kg, 5.1 ft•lb)
85 Nm (8.5 m•kg, 61 ft•lb)
5NX-9-30-5D 6/5/01 4:40 PM Page 2