2005 YAMAHA YZ250LC ECU

4-17
ENGCARBURETOR AND REED VALVE
2. Tighten:
9Screw (carburetor joint) 1
3. Tighten:
9Screw (air cleaner joint) 1
NOTE:
Place the screw head awith its top as shown
and secure the clamp in alignment with the hori-
zontal line bthat passes the center of the car-
buretor bore.
4. Connect:
9TPS (throttle position sensor) lead 1
9Solenoid valve lead 2
Refer to “CABLE ROUTING DIAGRAM”
section in the CHAPTER 2.
5. Adjust:
9Idle speed
Refer to “IDLE SPEED ADJUSTMENT”
section in the CHAPTER 3.
1P8-9-30-4A 11/5/04 9:32 PM Page 34

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.
CarburetorRefer 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.
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)
64 Nm (6.4 m•kg, 46 ft•lb)
75 Nm (7.5 m•kg, 54 ft•lb)
8 Nm (0.8 m•kg, 5.8 ft•lb)
34 Nm (3.4 m•kg, 24 ft•lb)
64 Nm (6.4 m•kg, 46 ft•lb)
85 Nm (8.5 m•kg, 61 ft•lb)
1P8-9-30-4C 21/5/04 12:59 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 Bolt (axle holder) 4 Only loosening.
2 Nut (front wheel axle) 1
3 Front wheel axle 1
4 Front wheel 1
5 Collar 2
6 Oil seal 2
7 Bearing 2 Refer to “REMOVAL POINTS”.
8 Brake disc 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.
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)
12 Nm (1.2 m•kg, 8.7 ft•lb)
1P8-9-30-5A 19/5/04 9:28 AM 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 disc 1
2
13
3
w
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)
16 Nm (1.6 m•kg, 11 ft•lb)
16 Nm (1.6 m•kg, 11 ft•lb)
42 Nm (4.2 m•kg, 30 ft•lb)
1P8-9-30-5A 19/5/04 9:28 AM 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 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 1Loosen when disassembling the caliper.
7 Caliper 1
8 Brake lever 1
9 Master cylinder bracket 1
10 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
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)
23 Nm (2.3 m•kg, 17 ft•lb)
30 Nm (3.0 m•kg, 22 ft•lb)
2
10 Nm (1.0 m•kg, 7.2 ft•lb)
7 Nm (0.7 m•kg, 5.1 ft•lb)
30 Nm (3.0 m•kg, 22 ft•lb)
1P8-9-30-5A 19/5/04 9:28 AM 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 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 1Loosen when disassembling the caliper.
8 Caliper 1
Extent of removal:1Master cylinder removal2Brake hose removal3Caliper removal
w
Support the machine securely so there is no dan-
ger of it falling over.
2
3
31
1
1 Nm (0.1 m•kg, 0.7 ft•lb)
30 Nm (3.0 m•kg, 22 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)
1P8-9-30-5A 19/5/04 9:28 AM Page 22

5-26
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 Pinch bolt (handle crown) 2 Only loosening.
3 Damper assembly 1
Loosen when disassembling the front fork.
Use special tool. Refer to “REMOVAL POINTS”.
4 Pinch bolt (under bracket) 2 Only loosening.
5 Front fork 1
1
w
Support the machine securely so there is no dan-
ger of it falling over.
Extent of removal:1Front fork removal
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
7 Nm (0.7 m•kg, 5.1 ft•lb)
20 Nm (2.0 m•kg, 14 ft•lb)
23 Nm (2.3 m•kg, 17 ft•lb)
EC550000
FRONT FORK
1P8-9-30-5B 20/5/04 2:11 PM Page 2

5-48
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.
Front fender
1 Steering shaft cap 1
2 Steering shaft nut 1
3 Front fork 2 Refer to “FRONT FORK” section.
4 Handle crown 1
5 Ring nut 1 Use special tool.
Refer to “REMOVAL POINTS”.
6 Under bracket 1
7 Bearing race cover 1
8 Bearing (upper) 1
9 Bearing (lower) 1 Refer to “REMOVAL POINTS”.
10 Bearing race 2 Refer to “REMOVAL POINTS”. Extent of removal:1Under bracket removal 2Bearing removal
2
1
w
Support the machine securely so there is no dan-
ger of it falling over.
145 Nm (14.5 m•kg, 105 ft•lb)
EC560000
STEERING
23 Nm (2.3 m•kg, 17 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)
4Nm (0.4 m•kg, 2.9 ft•lb)
1P8-9-30-5C 11/5/04 11:09 AM Page 16