2002 YAMAHA YZ125LC maintenance

2-7
SPECMAINTENANCE SPECIFICATIONS
EC212201
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing…
Front suspension: USA, CDN, ZA
EUROPE
AUS, NZ
Front fork travel
300 mm (11.8 in)←…
Fork spring free length
460 mm (18.1 in)←455 mm (17.9 in)
Spring rate, STD K=4.02 N/mm K=Approx.…
(0.410 kg/mm, 4.02 N/mm
23.0 lb/in) (0.410 kg/mm,
23.0 lb/in)
Optional spring/Spacer Yes←…
Oil capacity 573 cm
3←…
(20.2 Imp oz,
19.4 US oz)
Oil level
135 mm (5.31 in)←…
80~150 mm ←…
(From top of outer tube with inner tube(3.15~5.91 in)
and damper rod fully compressed
without spring.)
Oil grade Suspension oil ←…
“01”
Inner tube outer diameter 46 mm (1.81 in)←…
Front fork top end 5 mm (0.20 in)←…
Rear suspension: USA, CDN, ZA
EUROPE
AUS, NZ
Shock absorber travel
132 mm (5.20 in)←…
Spring free length
260 mm (10.24 in) 275 mm (10.83 in)…
Fitting length
248 mm (9.76 in)262 mm (10.31 in)…

240.5~258.5 mm 255.5~273.5 mm…
(9.47~10.18 in)
(10.06~10.77 in)
Spring rate, STD K=45.0 N/mm K=Approx.…
(4.60 kg/mm, 47.0 N/mm
257.6 lb/in) (4.80 kg/mm,
268.8 lb/in)
Optional spring Yes←…
Enclosed gas pressure 1,000 kPa ←…
(10 kg/cm
2,
142 psi)
Swingarm:
Swingarm free play limit
End…
1.0 mm (0.04 in)
Side clearance…
0.2~0.9 mm
(0.008~0.035 in)
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2-8
SPECMAINTENANCE SPECIFICATIONS
Item Standard Limit
Wheel:
Front wheel type Spoke wheel…
Rear wheel type Spoke wheel…
Front rim size/Material 21 ×1.60/Aluminum…
Rear rim size/Material 19 ×1.85/Aluminum…
Rim runout limit:
Radial…
2.0 mm (0.08 in)
Lateral … 2.0 mm (0.08 in)
Drive chain:
Type/Manufacturer DID520DMA2 SDH/DAIDO …
Number of links 111 links+joint …
Chain slack 40~50 mm (1.6~2.0 in) …
Chain length (10 links) … 152.5 mm (6.004 in)
Front disc brake:
Disc outside dia. ×Thickness 250 ×3.0 mm (9.84 ×0.12 in)…
Pad thickness 4.4 mm (0.17 in) 1.0 mm (0.04 in)
Master cylinder inside dia. 11.0 mm (0.433 in)…
Caliper cylinder inside dia. 27.0 mm (1.063 in) ×2…
Brake fluid type DOT #4…
Rear disc brake:
Disc outside dia. ×Thickness 245 ×4.0 mm (9.65 ×0.16 in)…
Deflection limit…
0.15 mm (0.006 in)
Pad thickness 6.4 mm (0.25 in) 1.0 mm (0.04 in)
Master cylinder inside dia. 12.7 mm (0.500 in)…
Caliper cylinder insdie dia. 27.0 mm (1.063 in)…
Brake fluid type DOT #4…
Brake lever & brake pedal:
Brake lever position 95 mm (3.74 in)…
Brake pedal height Zero mm (Zero in)…
(vertical height above footrest top)
Clutch lever free play (lever end) 8~13 mm (0.31~0.51 in)…
Throttle grip free play 3~5 mm (0.12~0.20 in)…
5NY-9-30-2A 5/24/01 8:03 PM Page 9

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

2-11
SPECMAINTENANCE SPECIFICATIONS
EC212300
ELECTRICAL
Part to be tightened Thread size Q’tyT ightening torqueNm m•kg ft•lb
Stator M 6 ×1.0 3 8 0.8 5.8
Rotor M10 ×1.25 1 33 3.3 24
Ignition coil M 6 ×1.0 2 7 0.7 5.1
Item Standard Limit
Ignition system:
Ignition timing (B.T.D.C.) 0.52 mm (0.020 in)…
Advancer type Electrical…
CDI:
Magneto-model (stator)/Manufacturer 4SS-01/YAMAHA…
Source coil 1 resistance (color) 720~1,080 Ωat 20°C (68°F)…
(Green/White-Black/Red)
Source coil 2 resistance (color) 44~66 Ωat 20°C (68°F)…
(Black-Green/Blue)
Pickup coil resistance (color) 248~372 Ωat 20°C (68°F)…
(White/Blue-White/Red)
CDI unit-model/Manufacturer 5NY-00/YAMAHA…
(Except for EUROPE)
5NY-10/YAMAHA…
(For EUROPE)
Ignition coil:
Model/Manufacturer 4SS-00/YAMAHA…
Minimum spark gap 6 mm (0.24 in)…
Primary winding resistance 0.14~0.20 Ωat 20°C (68°F)…
Secondary winding resistance 6.7~10.1kΩat 20°C (68°F)…
5NY-9-30-2A 5/24/01 8:03 PM Page 12

3-1
MAINTENANCE INTERVALS
INSP
ADJ
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
EC310052
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the required
maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in maintaining
and lubricating your machine, consult your Yamaha dealer.
Item Remarks
PISTON
Inspect and clean
Inspect crack
ReplaceRemove carbon
PISTON RING
InspectCheck ring end gap
Replace
PISTON PIN, SMALL END BEARING
Inspect
Replace
CYLINDER HEAD
Inspect and cleanRemove carbon
RetightenCheck gasket
CYLINDER
Inspect and clean
Inspect score marks
ReplaceInspect wear
YPVS
Inspect and clean
CLUTCHInspect housing, friction
Inspect and adjustplate, clutch plate and
Replacespring
TRANSMISSION
Replace oilYamalube 4 (10W-30) or
InspectSAE 10W-30 SE motor oil
Replace bearing
SHIFT FORK, SHIFT CAM, GUIDE BAR
InspectInspect wear
ROTOR NUT
Retighten
MUFFLER
Inspect
Clean
CRANK
Inspect and clean
CARBURETOR
Inspect, adjust and clean
SPARK PLUG
Inspect and clean
Replace
DRIVE CHAIN Use chain lube
Lubricate, slack, alignmentChain slack: 40~50 mm
Replace(1.6~2.0 in)
After
break-
inEvery
raceEvery
thirdEvery
fifthAs re-
quired
3
5NY-9-30-3A 5/23/01 8:24 PM Page 2

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