2012 YAMAHA YZ125LC wheel

2-9
TIGHTENING TORQUES
CHASSIS
△- marked portion shall be checked for torque tightening after break-in or before each race.
ItemThread
sizeQ'ty Tightening torque Remarks
△Upper bracket and outer tube M84 21 Nm (2.1 m•kg, 15 ft•lb)
△Lower bracket and outer tube M8 4 21 Nm (2.1 m•kg, 15 ft•lb)
△Upper bracket and steering stem M24 1 145 Nm (14.5 m•kg, 105 ft•lb)
△Handlebar upper holder M8 4 28 Nm (2.8 m•kg, 20 ft•lb)
△Handlebar lower holder M12 2 40 Nm (4.0 m•kg, 29 ft•lb)
△Steering ring nut M28 1 Refer to TIP.
Front fork and damper assembly M51 2 30 Nm (3.0 m•kg, 22 ft•lb)
Front fork and adjuster M22 2 55 Nm (5.5 m•kg, 40 ft•lb)Copper
washer
Damper assembly and base valve M42 2 29 Nm (2.9 m•kg, 21 ft•lb)
Adjuster and damper assembly M12 2 29 Nm (2.9 m•kg, 21 ft•lb)
Bleed screw (front fork) and base valve M5 2 1 Nm (0.1 m•kg, 0.7 ft•lb)
△Front fork and front fork protector M6 6 5 Nm (0.5 m•kg, 3.6 ft•lb)
△Cable guide (front brake hose) and lower
bracketM6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
△Front fork protector and brake hose hold-
erM6 2 8 Nm (0.8 m•kg, 5.8 ft•lb)
Throttle cable cap M4 2 1 Nm (0.1 m•kg, 0.7 ft•lb)
△Front brake master cylinder and bracket M6 2 9 Nm (0.9 m•kg, 6.5 ft•lb)
Brake lever mounting bolt M6 1 6 Nm (0.6 m•kg, 4.3 ft•lb)
Brake lever mounting nut M6 1 6 Nm (0.6 m•kg, 4.3 ft•lb)
Brake lever position locknut M6 1 5 Nm (0.5 m•kg, 3.6 ft•lb)
Clutch lever mounting nut M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Clutch lever holder M5 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Front brake master cylinder cap M4 2 2 Nm (0.2 m•kg, 1.4 ft•lb)
△Front brake hose union bolt (brake master
cylinder)M10 1 30 Nm (3.0 m•kg, 22 ft•lb)Copper
washer
△
Front brake hose union bolt (caliper) M10 1 30 Nm (3.0 m•kg, 22 ft•lb)Copper
washer
△Front brake caliper and front fork M8 2 28 Nm (2.8 m•kg, 20 ft•lb)
Grip cap upper and lower M6 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Brake caliper (front and rear) and pad pin
plugM10 2 3 Nm (0.3 m•kg, 2.2 ft•lb)
△Brake caliper (front and rear) and pad pin M10 2 18 Nm (1.8 m•kg, 13 ft•lb)
△Brake caliper (front and rear) and bleed
screwM8 2 6 Nm (0.6 m•kg, 4.3 ft•lb)
△Front wheel axle and axle nut M16 1 105 Nm (10.5 m•kg, 75 ft•lb)
△Front wheel axle holder M8 4 21 Nm (2.1 m•kg, 15 ft•lb)
△Front brake disc and wheel hub M6 6 12 Nm (1.2 m•kg, 8.7 ft•lb)
△Rear brake disc and wheel hub M6 6 14 Nm (1.4 m•kg, 10 ft•lb)
Footrest bracket and frame M10 4 55 Nm (5.5 m•kg, 40 ft•lb)TORX

2-10
TIGHTENING TORQUES
△Brake pedal mounting M8 1 26 Nm (2.6 m•kg, 19 ft•lb)
△Rear brake master cylinder and frame M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Rear brake master cylinder cap M4 2 2 Nm (0.2 m•kg, 1.4 ft•lb)
△
Rear brake hose union bolt (caliper) M10 1 30 Nm (3.0 m•kg, 22 ft•lb)Copper
washer
△Rear brake hose union bolt (master cylin-
der)M10 1 30 Nm (3.0 m•kg, 22 ft•lb)Copper
washer
△Rear wheel axle and axle nut M20 1 125 Nm (12.5 m•kg, 90 ft•lb)
△Nipple (spoke) — 72 3 Nm (0.3 m•kg, 2.2 ft•lb)
△Driven sprocket and wheel hub M8 6 42 Nm (4.2 m•kg, 30 ft•lb)
△Disc cover and rear brake caliper M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
△Protector and rear brake caliper M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Drive chain puller adjust bolt and locknut M8 2 19 Nm (1.9 m•kg, 13 ft•lb)
Engine :
△Engine and frame (front) M10 1 64 Nm (6.4 m•kg, 46 ft•lb)
△Engine and frame (lower) M10 1 64 Nm (6.4 m•kg, 46 ft•lb)
△Engine bracket and frame M8 2 34 Nm (3.4 m•kg, 24 ft•lb)
△Engine bracket and engine M8 1 34 Nm (3.4 m•kg, 24 ft•lb)
△Pivot shaft and nut M16 1 85 Nm (8.5 m•kg, 61 ft•lb)
△Relay arm and swingarm M14 1 70 Nm (7.0 m•kg, 50 ft•lb)
△Relay arm and connecting rod M14 1 80 Nm (8.0 m•kg, 58 ft•lb)
△Connecting rod and frame M14 1 80 Nm (8.0 m•kg, 58 ft•lb)
△Rear shock absorber and frame M10 1 56 Nm (5.6 m•kg, 40 ft•lb)
△Rear shock absorber and relay arm M10 1 53 Nm (5.3 m•kg, 38 ft•lb)
△Rear frame and frame (upper) M8 1 32 Nm (3.2 m•kg, 23 ft•lb)
△Rear frame and frame (lower) M8 2 29 Nm (2.9 m•kg, 21 ft•lb)
△Swingarm and brake hose holder M54 3 Nm (0.3 m•kg, 2.2 ft•lb)
Swingarm and patch M4 4 2 Nm (0.2 m•kg, 1.4 ft•lb)
Drive chain tensioner M8 2 16 Nm (1.6 m•kg, 11 ft•lb)
Drive chain support and swingarm M6 37 Nm (0.7 m•kg, 5.1 ft•lb)
Seal guard and swingarm M5 4 6 Nm (0.6 m•kg, 4.3 ft•lb)
Cable guide and frame M5 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
△Fuel tank boss and frame M10 2 20 Nm (2.0 m•kg, 14 ft•lb)
△Fuel tank M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
△Fuel tank and fuel cock M6 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Fuel tank and seat set bracket M6 1 7 Nm (0.7 m•kg, 5.1 ft•lb)
Fuel tank and hooking screw (fitting band) M6 1 7 Nm (0.7 m•kg, 5.1 ft•lb)
Fuel tank and fuel tank bracket M6 4 7 Nm (0.7 m•kg, 5.1 ft•lb)
△Air scoop and fuel tank M6 4 7 Nm (0.7 m•kg, 5.1 ft•lb)
△Air scoop and radiator guard (lower) M6 2 6 Nm (0.6 m•kg, 4.3 ft•lb)
△Front fender M6 4 7 Nm (0.7 m•kg, 5.1 ft•lb)
△Rear fender (front) M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
△Rear fender (rear) M6 2 12 Nm (1.2 m•kg, 8.7 ft•lb)
△Side cover M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Seat M8 2 19 Nm (1.9 m•kg, 13 ft•lb)ItemThread
sizeQ'ty Tightening torque Remarks

3-4
MAINTENANCE INTERVALS
TIRE, WHEELS
Inspect air pressure, wheel
run-out, tire wear and
spoke looseness●●
Retighten sprocket bolt●●
Inspect bearings●
Replace bearings●
Lubricate●Lithium base grease
THROTTLE, CONTROL CA-
BLE
Check routing and connec-
tion●●
Lubricate●●Yamaha cable lube or SAE
10W-40 motor oil ItemAfter
break-in
Every
race
(about
2.5
hours)Every
third
(about
7.5
hours)Every
fifth
(about
12.5
hours)
As re-
quiredRemarks

3-5
PRE-OPERATION INSPECTION AND MAINTENANCE
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator cap. Check the cool-
ing system for leakage.P. 3-6 – 7
FuelCheck that a fresh mixture of oil and gasoline is filled in the fuel
tank. Check the fuel line for leakage.P. 1-12
Transmission oilCheck that the oil level is correct. Check the crankcase for leak-
age.P. 3-8 – 9
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P. 3-7
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P. 3-7 – 8
Brakes Check the play of front brake and effect of front and rear brake. P. 3-9 – 12
Drive chainCheck drive chain slack and alignment. Check that the drive chain
is lubricated properly.P. 3-12 – 13
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P. 3-16
SteeringCheck that the handlebar can be turned smoothly and have no ex-
cessive play.P. 3-17
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage.
P. 3-13 – 16
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or when
the front forks travel up and down.—
Muffler Check that the muffler is tightly mounted and has no cracks. P. 4-3 – 4
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P. 3-12
Lubrication Check for smooth operation. Lubricate if necessary. P. 3-18
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P. 1-13
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P. 1-7
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs be-
fore racing? Are inspection and maintenance completely done?P. 7-1 – 11

3-11
CHASSIS
2. Replace:
• Brake pad
Brake pad replacement steps:
a. Remove the pad pin plug "1".
b. Loosen the pad pin "2".
c. Remove the brake caliper "3"
from the front fork.
d. Remove the pad pin and brake
pads "4".
e. Connect the transparent hose "5"
to the bleed screw "6" and place
the suitable container under its
end.
f. Loosen the bleed screw and push
the brake caliper piston in.
Do not reuse the drained brake flu-
id.
g. Tighten the bleed screw.
h. Install the brake pads "7" and pad
pin.
• Install the brake pads with their pro-
jections "a" into the brake caliper re-
cesses "b".
• Temporarily tighten the pad pin at
this point.
i. Install the brake caliper "8" and
tighten the pad pin "9".
j. Install the pad pin plug "10".
3. Inspect:
• Brake fluid level
Refer to "CHECKING THE
BRAKE FLUID LEVEL" section.
4. Check:
• Brake lever operation
A softy or spongy feeling→Bleed
brake system.
Refer to "BLEEDING THE HY-
DRAULIC BRAKE SYSTEM" sec-
tion.CHECKING AND REPLACING THE
REAR BRAKE PADS
1. Inspect:
• Brake pad thickness "a"
Out of specification→Replace as
a set.
2. Replace:
• Brake pad
Brake pad replacement steps:
a. Remove the protector "1" and pad
pin plug "2".
b. Loosen the pad pin "3".
c. Remove the rear wheel "4" and
brake caliper "5".
Refer to "FRONT WHEEL AND
REAR WHEEL" section in the
CHAPTER 5.
d. Remove the pad pin "6" and brake
pads "7".
Bleed screw:
6 Nm (0.6 m•kg, 4.3
ft•lb)
Bolt (brake caliper):
28 Nm (2.8 m•kg, 20
ft•lb)
Pad pin:
18 Nm (1.8 m•kg, 13
ft•lb)
Pad pin plug:
3 Nm (0.3 m•kg, 2.2
ft•lb)
Brake pad thickness:
6.4 mm (0.25 in)
: 1.0 mm (0.04
in)

3-12
CHASSIS
e. Connect the transparent hose "8"
to the bleed screw "9" and place
the suitable container under its
end.
f. Loosen the bleed screw and push
the brake caliper piston in.
Do not reuse the drained brake flu-
id.
g. Tighten the bleed screw.
h. Install the brake pad "10" and pad
pin "11".
• Install the brake pads with their pro-
jections "a" into the brake caliper re-
cesses "b".
• Temporarily tighten the pad pin at
this point.
i. Install the brake caliper "12" and
rear wheel "13".
Refer to "FRONT WHEEL AND
REAR WHEEL" section in the
CHAPTER 5.
j. Tighten the pad pin "14".k. Install the pad pin plug "15" and
protector "16".
3. Inspect:
• Brake fluid level
Refer to "CHECKING THE
BRAKE FLUID LEVEL" section.
4. Check:
• Brake pedal operation
A softy or spongy feeling→Bleed
brake system.
Refer to "BLEEDING THE HY-
DRAULIC BRAKE SYSTEM" sec-
tion.
CHECKING THE REAR BRAKE
PAD INSULATOR
1. Remove:
•Brake pad
Refer to "CHECKING AND RE-
PLACING THE REAR BRAKE
PADS" section.
2. Inspect:
• Rear brake pad insulator "1"
Damage→Replace.
CHECKING THE BRAKE FLUID
LEVEL
1. Place the brake master cylinder
so that its top is in a horizontal po-
sition.
2. Inspect:
• Brake fluid level
Fluid at lower level→Fill up.
• 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 perfor-
mance.
• Be sure that water or other con-
taminants do not enter master
cylinder when refilling.
• Clean up spilled fluid immediate-
ly to avoid erosion of painted
surfaces or plastic parts.
a. Lower level
A. Front
B. Rear
CHECKING THE SPROCKET
1. Inspect:
• Sprocket teeth "a"
Excessive wear→Replace.
Replace the drive sprocket, rear
wheel sprocket and drive chain as a
set.
CHECKING THE DRIVE CHAIN
1. Measure:
• Drive chain length (15 links) "a"
Out of specification→Replace.
• While measuring the drive chain
length, push down on the drive
chain to increase its tension.
• Measure the length between drive
chain roller "1" and "16" as shown.
• Perform this measurement at two or
three different places.
Bleed screw:
6 Nm (0.6 m•kg, 4.3
ft•lb)
Pad pin:
18 Nm (1.8 m•kg, 13
ft•lb)
Pad pin plug:
3 Nm (0.3 m•kg, 2.2
ft•lb)
Bolt (protector):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Recommended brake flu-
id:
DOT #4
Drive chain length (15
links):
: 242.9 mm
(9.563 in)

3-13
CHASSIS
2. Remove:
• Master link clip
•Joint "1"
• Drive chain "2"
3. Clean:
• Drive chain
Place it in kerosene, and brush off
as much dirt as possible. Then re-
move the drive chain from the ker-
osene and dry the drive chain.
4. Check:
• Drive chain stiffness "a"
Clean and oil the drive chain and
hold as illustrated.
Stiff→Replace the drive chain.
5. Install:
• Drive chain "1"
•Joint "2"
• Master link clip "3"
Be sure to install the master link
clip to the direction as shown.
a. Turning direction6. Lubricate:
• Drive chain
ADJUSTING THE DRIVE CHAIN
SLACK
1. Elevate the rear wheel by placing
the suitable stand under the en-
gine.
2. Check:
• Drive chain slack "a"
Above the seal guard installation
bolt.
Out of specification→Adjust.
Before checking and/or adjusting, ro-
tate the rear wheel through several
revolutions and check the slack sev-
eral times to find the tightest point.
Check and/or adjust the drive chain
slack with the rear wheel in this "tight
chain" position.
3. Adjust:
• Drive chain slack
Drive chain slack adjustment
steps:
a. Loosen the axle nut "1" and lock-
nuts "2".
b. Adjust the drive chain slack by
turning the adjusters "3".c. 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.) NOTICE: Im-
proper drive chain slack will
overload the engine as well as
other vital parts of the motorcy-
cle and can lead to chain slip-
page or breakage. To prevent
this from occurring, keep the
drive chain slack within the
specified limits.
Turn the adjuster so that the drive
chain is in line with the sprocket, as
viewed from the rear.
d. Tighten the axle nut while pushing
down the drive chain.
e. Tighten the locknuts.
CHECKING THE FRONT FORK
1. Inspect:
• Front fork smooth action
Operate the front brake and
stroke the front fork.
Unsmooth action/oil leakage→
Repair or replace.
Drive chain lubricant:
SAE 10W-40 motor oil
or suitable chain lubri-
cants
Drive chain slack:
48–58 mm (1.9–2.3 in)
To tighten→Turn the adjuster "3"
counterclockwise.
To loosen→Turn the adjuster "3"
clockwise and push wheel for-
ward.
Axle nut:
125 Nm (12.5 m•kg, 90
ft•lb)
Locknut:
19 Nm (1.9 m•kg, 13
ft•lb)

3-14
CHASSIS
CLEANING THE FRONT FORK OIL
SEAL AND DUST SEAL
1. Remove:
•Protector
• Dust seal "1"
Use a thin screw driver, and be care-
ful not to damage the inner fork tube
and dust seal.
2. Clean:
• Dust seal "a"
• Oil seal "b"
• Clean the dust seal and oil seal af-
ter every run.
• Apply the lithium soap base grease
on the inner tube.
RELIEVING THE FRONT FORK
INTERNAL PRESSURE
If the front fork initial movement feels
stiff during a run, relieve the front fork
internal pressure.
1. Elevate the front wheel by placing
a suitable stand under the engine.
2. Remove the air bleed screw "1"
and release the internal pressure
from the front fork.
3. Install:
• Air bleed screwADJUSTING THE FRONT FORK
REBOUND DAMPING FORCE
1. Adjust:
• Rebound damping force
By turning the adjuster "1".
• STANDARD POSITION:
This is the position which is back
by the specific number of clicks
from the fully turned-in position.
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
Always adjust each front fork to
the same setting. Uneven adjust-
ment can cause poor handling and
loss of stability.
ADJUSTING THE FRONT FORK
COMPRESSION DAMPING FORCE
1. Adjust:
• Compression damping force
By turning the adjuster "1".• STANDARD POSITION:
This is the position which is back
by the specific number of clicks
from the fully turned-in position.
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
Always adjust each front fork to
the same setting. Uneven adjust-
ment can cause poor handling and
loss of stability.
CHECKING THE REAR SHOCK
ABSORBER
1. Inspect:
• Swingarm smooth action
Abnormal noise/unsmooth action
→Grease the pivoting points or
repair the pivoting points.
Damage/oil leakage→Replace.
ADJUSTING THE REAR SHOCK
ABSORBER SPRING PRELOAD
1. Elevate the rear wheel by placing
the suitable stand under the en-
gine.
2. Remove:
• Rear frame Air bleed screw:
1 Nm (0.1 m•kg, 0.7
ft•lb)
Stiffer "a" →Increase the re-
bound damping force. (Turn
the adjuster "1" in.)
Softer "b" →Decrease the re-
bound damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position20 clicks out
(from maximum
position)
Standard position:
14 clicks out
* 13 clicks out
* For EUROPE
Stiffer "a" →Increase the com-
pression damping force. (Turn
the adjuster "1" in.)
Softer "b" →Decrease the com-
pression damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position20 clicks out
(from maximum
position)
Standard position:
13 clicks out
* 12 clicks out
* For EUROPE