brake YAMAHA YZ125LC 2012 Owner's Manual

4-23
KICK SHAFT AND SHIFT SHAFT
KICK SHAFT AND SHIFT SHAFT
REMOVING THE PRIMARY DRIVE GEAR
Order Part name Q'ty Remarks
Drain the transmission oil. Refer to "CHANGING THE TRANSMISSION
OIL" section in the CHAPTER 3.
Clutch cable Disconnect at engine side.
Bolt (brake pedal) Shift the brake pedal downward.
Radiator hose 4 Disconnect at water pump side.
Bolt (push rod)Refer to "CYLINDER HEAD, CYLINDER
AND PISTON" section.
1 Kickstarter crank 1
2 Crankcase cover (right) 1
3 Bolt (Primary drive gear) 1 Only loosening. Refer to removal section.
4 Primary driven gear 1 Refer to "CLUTCH" section.
5 Primary drive gear 1

4-35
ENGINE REMOVAL
ENGINE REMOVAL
REMOVING THE ENGINE
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.Refer to "HANDLING NOTE".
Seat and fuel tank Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
Carburetor Refer to "CARBURETOR AND REED
VALVE" section.
Exhaust pipe and silencer Refer to "EXHAUST PIPE AND SILENCER"
section.
Clutch cable Disconnect at the engine side.
Radiator Refer to "RADIATOR" section.
Spark plug cap
Disconnect the CDI magneto lead.
1 Drive chain sprocket cover 1
2 Nut (drive sprocket) 1 Refer to removal section.
3 Lock washer 1 Refer to removal section.
4 Drive sprocket 1 Refer to removal section.
5Clip 1
6 Bolt (brake pedal) 1
26 Nm (2.6 m kg, 19 ft lb)
64 Nm (6.4 m kg, 46 ft lb)
64 Nm (6.4 m kg, 46 ft lb)
85 Nm (8.5 m kg, 61 ft lb)
75 Nm (7.5 m kg, 54 ft lb)
5 Nm (0.5 m kg, 3.6 ft lb)
34 Nm (3.4 m kg, 24 ft lb)

4-36
ENGINE REMOVAL
7 Brake pedal 1
8 Engine bracket 2
9 Engine mounting bolt 3
10 Pivot shaft 1 Refer to removal section.
11 Engine 1 Refer to removal section. Order Part name Q'ty Remarks
26 Nm (2.6 m kg, 19 ft lb)
64 Nm (6.4 m kg, 46 ft lb)
64 Nm (6.4 m kg, 46 ft lb)
85 Nm (8.5 m kg, 61 ft lb)
75 Nm (7.5 m kg, 54 ft lb)
5 Nm (0.5 m kg, 3.6 ft lb)
34 Nm (3.4 m kg, 24 ft lb)

4-37
ENGINE REMOVAL
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
REMOVING THE DRIVE
SPROCKET
1. Remove:
• Nut (drive sprocket) "1"
• Lock washer "2"
• Straighten the lock washer tab.
• Loosen the nut while applying the
rear brake.
2. Remove:
• Drive sprocket "1"
• Drive chain "2"
Remove the drive sprocket together
with the drive chain.
REMOVING THE ENGINE
1. Remove:
• Pivot shaft "1"
If the pivot shaft is pulled all the way
out, the swingarm will come loose. If
possible, insert a shaft of similar di-
ameter into the other side of the swin-
garm to support it.
2. Remove:
• Engine "1"
From right side.
Make sure that the couplers, hoses
and cables are disconnected.
INSTALLING THE ENGINE
1. Install:
• Engine "1"
Install the engine from right side.
• Pivot shaft "2"
• Engine mounting bolt (lower) "3"
• Engine mounting bolt (front) "4"
• Engine bracket "5"
• Bolt (engine bracket) "6"
• Engine mounting bolt (upper) "7"
Apply the molybdenum disulfide
grease on the pivot shaft.
INSTALLING THE BRAKE PEDAL
1. Install:
• Spring "1"
• Brake pedal "2"
• O-ring "3"
• Bolt (brake pedal) "4"
• Clip "5"
Apply the lithium soap base grease
on the bolt, O-rings and brake pedal
bracket.
INSTALLING THE DRIVE
SPROCKET
1. Install:
• Drive sprocket "1"
• Drive chain "2"
Install the drive sprocket together
with the drive chain.
2. Install:
• Lock washer "1"
• Nut (drive sprocket) "2"
Tighten the nut while applying the
rear brake.
3. Bend the lock washer tab to lock
the nut.
Pivot shaft:
85 Nm (8.5 m•kg, 61
ft•lb)
Engine mounting bolt
(lower):
64Nm (6.4 m•kg, 46
ft•lb)
Engine mounting bolt
(front):
64 Nm (6.4 m•kg, 46
ft•lb)
Bolt (engine bracket):
34 Nm (3.4 m•kg, 24
ft•lb)
Engine mounting bolt
(upper):
34 Nm (3.4 m•kg, 24
ft•lb)
Bolt (brake pedal):
26 Nm (2.6 m•kg, 19
ft•lb)
Nut (drive sprocket):
75 Nm (7.5 m•kg, 54
ft•lb)

5-1
FRONT WHEEL AND REAR WHEEL
CHASSIS
This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles
(e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request-
ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual. It may lead to
servicing trouble and mechanical damage.
FRONT WHEEL AND REAR WHEEL
REMOVING THE FRONT WHEEL
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.Refer to "HANDLING NOTE".
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 section.
8 Brake disc 1
5

5-2
FRONT WHEEL AND REAR WHEEL
REMOVING THE REAR WHEEL
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.Refer to "HANDLING NOTE".
1 Nut (rear wheel axle) 1
2 Rear wheel axle 1
3 Drive chain puller 2
4 Rear wheel 1 Refer to removal section.
5 Collar 2
6 Rear wheel sprocket 1
7 Oil seal 2
8 Circlip 1
9 Bearing 2 Refer to removal section.
10 Brake disc 1

5-3
FRONT WHEEL AND REAR WHEEL
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
REMOVING THE REAR WHEEL
1. Remove:
• Wheel "1"
Push the wheel forward and remove
the drive chain "2".
REMOVING THE WHEEL BEARING
1. Remove:
• Bearing "1"
Remove the bearing using a general
bearing puller "2".
CHECKING THE WHEEL
1. Measure:
• Wheel runout
Out of limit → Repair/replace.
2. Inspect:
• Bearing
Rotate inner race with a finger.
Rough spot/seizure → Replace.
Replace the bearings, oil seal and
wheel collar as a set.
CHECKING THE WHEEL AXLE
1. Measure:
• Wheel axle bends
Out of specification → Replace.
Use the dial gauge "1".
The bending value is shown by one
half of the dial gauge reading.
Do not attempt to straighten a bent
axle.
CHECKING THE BRAKE DISC
1. Measure:
• Brake disc deflection (only rear
brake disc)
Use the dial gauge "1".
Out of specification → Inspect
wheel runout.
If wheel runout is in good condi-
tion, replace the brake disc.
2. Measure:
• Brake disc thickness "a"
Out of limit → Replace.INSTALLING THE FRONT WHEEL
1. Install:
• Bearing (left) "1"
• Spacer "2"
• Bearing (right) "3"
• Oil seal "4"
• Apply the lithium soap base grease
on the bearing and oil seal lip when
installing.
• Use a socket that matches the out-
side diameter of the race of the
bearing.
• Left side of bearing shall be in-
stalled first.
• Install the oil seal with its manufac-
ture's marks or numbers facing out-
ward.
Do not strike the inner race of the
bearing. Contact should be made
only with the outer race.
Wheel runout limit:
Radial "1": 2.0 mm
(0.08 in)
Lateral "2": 2.0 mm
(0.08 in)
Wheel axle bending limit:
0.5 mm (0.020 in)
Brake disc deflection lim-
it:
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)

5-4
FRONT WHEEL AND REAR WHEEL
2. Install:
• Brake disc "1"
• Bolt (brake disc) "2"
Tighten the bolts in stage, using a
crisscross pattern.
3. Install:
•Collar "1"
• Apply the lithium soap base grease
on the oil seal lip.
• Install the collars with their projec-
tions "a" facing the wheel.
4. Install:
• Wheel
Install the brake disc "1" between the
brake pads "2" correctly.
5. Install:
• Wheel axle "1"
Apply the lithium soap base grease
on the wheel axle.
6. Install:
• Nut (wheel axle) "1"
7. Tighten:
• Bolt (axle holder) "1"
Before tightening the bolt, fit the
wheel axle to the axle holder by strok-
ing the front fork several times with
the front brake applied.
INSTALLING THE REAR WHEEL
1. Install:
• Bearing (right) "1"
• Circlip "2"
• Spacer "3"
• Bearing (left) "4"
• Oil seal "5"
• Apply the lithium soap base grease
on the bearing and oil seal lip when
installing.
• Install the bearing with seal facing
outward.
• Use a socket that matches the out-
side diameter of the race of the
bearing.
• Right side of bearing shall be in-
stalled first.
• Install the oil seal with its manufac-
ture's marks or numbers facing out-
ward.
Do not strike the inner race of the
bearing. Contact should be made
only with the outer race.
2. Install:
• Brake disc "1"
• Bolt (brake disc) "2"
Tighten the bolts in stage, using a
crisscross pattern.
3. Install:
• Rear wheel sprocket "1"
• Bolt (rear wheel sprocket) "2"
• Washer (rear wheel sprocket) "3"
• Nut (rear wheel sprocket) "4"
Tighten the nuts in stage, using a
crisscross pattern.
Bolt (brake disc):
12 Nm (1.2 m•kg, 8.7
ft•lb)
Nut (wheel axle):
105 Nm (10.5 m•kg, 75
ft•lb)
Bolt (axle holder):
21 Nm (2.1 m•kg, 15
ft•lb)
Bolt (brake disc):
14 Nm (1.4 m•kg, 10
ft•lb)
Nut (rear wheel sprock-
et):
42 Nm (4.2 m•kg, 30
ft•lb)

5-5
FRONT WHEEL AND REAR WHEEL
4. Install:
•Collar "1"
Apply the lithium soap base grease
on the oil seal lip.
5. Install:
• Wheel
Install the brake disc "1" between the
brake pads "2" correctly.
6. Install:
• Drive chain "1"
Push the wheel "2" forward and install
the drive chain.
7. Install:
• Left drive chain puller "1"
• Wheel axle "2"
• Install the left drive chain puller, and
insert the wheel axle from left side.
• Apply the lithium soap base grease
on the wheel axle.
8. Install:
• Right drive chain puller "1"
• Washer "2"
• Nut (wheel axle) "3"
Temporarily tighten the nut (wheel
axle) at this point.
9. Adjust:
• Drive chain slack "a"
Refer to "ADJUSTING THE
DRIVE CHAIN SLACK" section in
the CHAPTER 3.
10. Tighten:
• Nut (wheel axle) "1"
• Locknut "2"
Drive chain slack:
48–58 mm (1.9–2.3 in)
Nut (wheel axle):
125 Nm (12.5 m•kg, 90
ft•lb)
Locknut:
19 Nm (1.9 m•kg, 13
ft•lb)

5-6
FRONT BRAKE AND REAR BRAKE
FRONT BRAKE AND REAR BRAKE
REMOVING THE FRONT BRAKE
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.Refer to "HANDLING NOTE".
Drain the brake fluid. Refer to removal section.
1 Brake hose holder (protector) 2
2 Union bolt 2
3 Brake hose 1
4 Pad pin plug 1 Remove when loosening the pad pin.
5Pad pin 1Loosen when disassembling the brake cali-
per.
6 Brake caliper 1
7Brake lever 1
8 Brake master cylinder bracket 1
9 Brake master cylinder 1