2002 YAMAHA YZ125LC wheel

2-9
SPECMAINTENANCE SPECIFICATIONS
NOTE:
1. First, tighten the ring nut approximately 38 Nm (3.8 m•kg, 27 ft•lb) by using the ring nut wrench,
then loosen the ring nut one turn.
2. Retighten the ring nut 7 Nm (0.7 m•kg, 5.1 ft•lb).
Part to be tightened Thread size Q'tyT ightening torqueNm m•kg ft•lb
Handle crown and outer tube M 8 ×1.25 4 23 2.3 17
Under bracket and outer tube M 8 ×1.25 4 20 2.0 14
Handle crown and steering shaft M24 ×1.0 1 145 14.5 105
Handlebar holder (upper) M 8 ×1.25 4 28 2.8 20
Steering ring nut M28 ×1.0 1 Refer to NOTE
Front fork and cap bolt M48 ×1.0 2 30 3.0 22
Front fork and base valve M30 ×1.0 2 55 5.5 40
Cap bolt and damper rod (front fork) M12 ×1.25 2 29 2.9 21
Bleed screw (front fork) and cap bolt M 5 ×0.8 2 1 0.1 0.7
Front fork and protector M 6 ×1.0 6 10 1.0 7.2
Cable guide (front brake hose) and guide stayM 5 ×0.8 1 4 0.4 2.9
Front fork and brake hose holder M 6 ×1.0 2 10 1.0 7.2
Front fork and hose cover M 8 ×1.25 1 16 1.6 11
Front fork and hose cover M 6 ×1.0 1 7 0.7 5.1
Throttle cable cap M 4 ×0.7 2 1 0.1 0.7
Front brake master cylinder and bracket M 6 × 1.0 2 9 0.9 6.5
Brake lever (bolt) M 6 ×1.0 1 6 0.6 4.3
(nut) M 6 ×1.0 1 6 0.6 4.3
Brake lever position locknut M 6 ×1.0 1 5 0.5 3.6
Clutch lever (bolt) M 6 ×1.0 1 2 0.2 1.4
Clutch lever holder M 5 ×0.8 2 4 0.4 2.9
Front brake master cylinder cap M 4 ×0.7 2 2 0.2 1.4
Front brake hose union bolt (master cylinder)M10 ×1.25 1 30 3.0 22
Front brake hose union bolt (caliper) M10 ×1.25 1 30 3.0 22
Front brake caliper and front fork M 8 ×1.25 2 23 2.3 17
Grip cap upper and lower M 6 ×1.0 2 4 0.4 2.9
Brake caliper (front and rear) and pad pin plugM10 ×1.0 1 3 0.3 2.2
Brake caliper (front and rear) and pad pin M10 ×1.0 1 18 1.8 13
Brake caliper (front and rear) and bleed screwM 8 ×1.25 1 6 0.6 4.3
Front wheel axle and nut M16 ×1.5 1 105 10.5 75
Front wheel axle holder M 8 ×1.25 4 23 2.3 17
Front brake disc and wheel hub M 6 ×1.0 6 12 1.2 8.7
Rear brake disc and wheel hub M 6 ×1.0 6 14 1.4 10
Brake pedal mounting M 8 ×1.25 1 26 2.6 19
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5NY-9-30-2A 5/24/01 8:03 PM Page 10

2-10
SPECMAINTENANCE SPECIFICATIONS
Part to be tightened Thread size Q'tyT ightening torqueNm m•kg ft•lb
Rear brake master cylinder and frame M 6 ×1.0 2 10 1.0 7.2
Rear brake reservoir tank and frame M 6 ×1.0 1 7 0.7 5.1
Rear brake hose union bolt (caliper) M10 ×1.25 1 30 3.0 22
Rear brake hose union bolt (master cylinder) M10 ×1.25 1 30 3.0 22
Rear wheel axle and nut M20 ×1.5 1 125 12.5 90
Nipple (spoke) – 72 3 0.3 2.2
Driven sprocket and wheel hub M 8 ×1.25 6 42 4.2 30
Disc cover and rear brake caliper M 6 ×1.0 2 7 0.7 5.1
Protector and rear brake caliper M 6 ×1.0 2 7 0.7 5.1
Engine mounting:
Engine and frame (front) M10 ×1.25 1 69 6.9 50
Engine and frame (lower) M10 ×1.25 1 69 6.9 50
Engine bracket and frame M 8 ×1.25 2 34 3.4 24
Engine bracket and engine M 8 ×1.25 1 34 3.4 24
Pivot shaft and nut M16 ×1.5 1 85 8.5 61
Relay arm and swingarm M14 ×1.5 1 80 8.0 58
Relay arm and connecting rod M14 ×1.5 1 80 8.0 58
Connecting rod and frame M14 ×1.5 1 80 8.0 58
Rear shock absorber and frame M10 ×1.25 1 56 5.6 40
Rear shock absorber and relay arm M10 ×1.25 1 53 5.3 38
Rear frame and frame M 8 ×1.25 3 29 2.9 21
Swingarm and brake hose holder M 5 ×0.8 4 2 0.2 1.4
Chain tensioner mounting M 8 ×1.25 2 19 1.9 13
Chain support and swingarm M 6 ×1.0 3 7 0.7 5.1
Seal guard and swingarm M 5 ×0.8 4 6 0.6 4.3
Fuel tank mounting M 6 ×1.0 2 10 1.0 7.2
Fuel tank and fuel cock M 6 ×1.0 2 7 0.7 5.1
Fuel tank and seat set bracket M 6 ×1.0 1 7 0.7 5.1
Fuel tank and hooking screw (fitting band) M 6 ×1.0 1 7 0.7 5.1
Fuel tank and fuel tank bracket M 6 ×1.0 4 7 0.7 5.1
Air scoop mounting M 6 ×1.0 6 4 0.4 2.9
Front fender mounting M 6 ×1.0 4 7 0.7 5.1
Rear fender mounting M 6 ×1.0 4 7 0.7 5.1
Side cover mounting M 6 ×1.0 2 7 0.7 5.1
Seat mounting M 8 ×1.25 2 19 1.9 13
Number plate M 6 ×1.0 1 7 0.7 5.1
NOTE:

- marked portion shall be checked for torque tightening after break-in or before each race.


 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5NY-9-30-2A 5/24/01 8:03 PM Page 11

2-14
SPECCABLE ROUTING DIAGRAM
LPass the radiater breather
hose and CDI magneto
lead between the frame and
radiator.
MAlign the top of the brake hose
neck with the brake hose
holder bottom.
NPass the brake hose in front
of the axle boss, then fit it
into the hose groove so that
the brake hose does not
contact the nut (wheel axle).
OFit the brake hose into the
guide on the protector.
PPosition each lead at the lower
left of the main tube (frame)
and put the clamp ends within
the area as shown by the
arrow.
5NY-9-30-2B 5/23/01 8:03 PM Page 28

3-2
MAINTENANCE INTERVALS
INSP
ADJ
Item Remarks
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolantEvery two years
Inspect hoses
OUTSIDE NUTS AND BOLTS Refer to “STARTING
RetightenAND BREAK-IN” section
in the CHAPTER 1.
AIR FILTER
Clean and lubricateUse foam air-filter oil
Replace
FRAME
Clean and inspect
FUEL TANK, COCK
Clean and inspect
BRAKES
Adjust lever position and pedal height
Lubricate pivot point
Check brake disc surface
Check fluid level and leakage
Retighten brake disc bolts, caliper bolts,

master cylinder bolts and union bolts
Replace pads
Replace brake fluidEvery one year
FRONT FORKS
Inspect and adjust
Replace oilSuspension oil “01”
Replace oil seal
FRONT FORK OIL SEAL AND DUST SEAL
Clean and lubeLithium base grease
REAR SHOCK ABSORBER
(After
Inspect and adjustrain ride)
Lube Molybdenum disulfide grease
Retighten
CHAIN GUARD AND ROLLERS
Inspect
SWINGARM
Inspect, lube and retightenMolybdenum disulfide grease
RELAY ARM, CONNECTING ROD
Inspect, lube and retightenMolybdenum disulfide grease
STEERING HEAD
Inspect free play and retighten
Clean and lubeLithium base grease
Replace bearing
TIRE, WHEELS
Inspect air pressure, wheel run-out,

tire wear and spoke looseness
Retighten sprocket bolt
Inspect bearings
Replace bearings
LubricateLithium base grease
THROTTLE, CONTROL CABLE
Check routing and connectionYamaha cable lube or
LubricateSAE 10W-30 motor oil
After
break-
inEvery
raceEvery
thirdEvery
fifthAs re-
quired
3
5NY-9-30-3A 5/23/01 8:24 PM Page 3

3-4
PRE-OPERATION INSPECTION AND MAINTENANCE
INSP
ADJ
EC320000
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.
EC321000
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
Coolant Check that coolant is filled up to the radiator filler cap.
Check the cooling system for leakage.P3-5~9
Fuel Check that a fresh mixture of oil and gasoline is filled in
the fuel tank. Check the fuel line for leakage.P1-12
Transmission oil Check that the oil level is correct. Check the crankcase
for leakage.P3-12~14
Gear shifter and clutch Check that gears can be shifted correctly in order and
that the clutch operates smoothly.P3-9
Throttle grip/Housing Check that the throttle grip operation and free play
are correctly adjusted. Lubricate the throttle grip and P3-10~11
housing, if necessary.
Brakes Check the play of front brake and effect of front and
rear brake.P3-17~23
Chain Check chain slack and alignment. Check that the chain
is lubricated properly.P3-24~26
Wheels Check for excessive wear and tire pressure. Check for
loose spokes and have no excessive play.P3-34~35
Steering Check that the handlebar can be turned smoothly and
have no excessive play.P3-35~36
Front forks and Check that they operate smoothly and there is no oil
rear shock absorber leakage.P3-26~33
Cables (wires) Check that the clutch and throttle cables move smooth-
ly. 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.P3-15~16
Sprocket Check that the driven sprocket tightening bolt is
not loose.P3-24
Lubrication Check for smooth operation. Lubricate if necessary. P3-37
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P1-16
Lead connectors Check that the CDI magneto, CDI unit, and ignition coil
are connected tightly.P1-6
Settings Is the machine set suitably for the condition of the
racing course and weather or by taking into account the
P7-1~24
results of test runs before racing? Are inspection and
maintenance completely done?
5NY-9-30-3A 5/23/01 8:24 PM Page 14

3-21
REAR BRAKE PAD INSPECTION AND REPLACEMENT
INSP
ADJ
3. Inspect:
9Brake fluid level
Refer to “BRAKE FLUID LEVEL
INSPECTION” section.
4. Check:
9Brake lever operation
A softy or spongy feeling Bleed brake
system.
Refer to “BRAKE SYSTEM AIR BLEED-
ING” section.
EC366060
REAR BRAKE PAD INSPECTION AND
REPLACEMENT
1. Inspect:
9Brake pad thickness a
Out of specification Replace as a set.
2. Replace:
9Brake pad
9Install the pad pin plug w.
Pad pin plug:
3 Nm (0.3 m•kg, 2.2 ft•lb)
Brake pad thickness a a
:
Standard
6.4 mm (0.25 in)
1.0 mm (0.04 in)
Brake pad replacement steps:
9Remove the protector 1and pad pin plug
2.
9Loosen the pad pin 3.
9Remove the rear wheel 4and caliper 5.
Refer to “FRONT WHEEL AND REAR
WHEEL” section in the CHAPTER 5.
5NY-9-30-3B 5/23/01 8:33 PM Page 6

3-22
REAR BRAKE PAD INSPECTION AND REPLACEMENT
INSP
ADJ
9Remove the pad pin 6and brake pads 7.
9Connect the transparent hose 8to the
bleed screw 9and place the suitable con-
tainer under its end.
9Loosen the bleed screw and push the
caliper piston in.
cC
Do not reuse the drained brake fluid.
9Tighten the bleed screw.
9Install the brake pads 0and pad pin q.
NOTE:
9Install the brake pads with their projections
ainto the caliper recesses b.
9Temporarily tighten the pad pin at this point.
9Install the caliper wand rear wheel e.
Refer to “FRONT WHEEL AND REAR
WHEEL” section in the CHAPTER 5.
9Tighten the pad pin r.
9Install the pad pin plug tand protector y.
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)
3. Inspect:
9Brake fluid level
Refer to “BRAKE FLUID LEVEL
INSPECTION” section.
4. Check:
9Brake pedal operation
A softy or spongy feeling Bleed brake
system.
Refer to “BRAKE SYSTEM AIR BLEEDING”
section.
5NY-9-30-3B 5/23/01 8:33 PM Page 8

3-25
DRIVE CHAIN SLACK ADJUSTMENT
INSP
ADJ
EC36A060
DRIVE CHAIN SLACK ADJUSTMENT
1. Elevate the rear wheel by placing the suit-
able stand under the engine.
2. Check:
9Drive chain slack a
Above the seal guard installation bolt.
Out of specification Adjust
NOTE:
Before checking and/or adjusting, rotate the rear
wheel through several revolutions and check the
slack several times to find the tightest point. Check
and/or adjust chain slack with rear wheel in this
“tight chain” position.
Drive chain slack:
40~50 mm (1.6~2.0 in)
Drive chain lubricant:
SAE 10W-30 motor oil or suitable
chain lubricants
5. Install:
9Drive chain 1
9Joint 2
9Master link clip 3
cC
Be sure to install the master link clip to the
direction as shown.
aTurning direction
6. Lubricate:
9Drive chain
5NY-9-30-3B 5/23/01 8:33 PM Page 14