2005 YAMAHA YZ125LC steering

CHAPTER 4
ENGINE
SEAT, FUEL TANK AND SIDE
COVERS.....................................................4-1
EXHAUST PIPE AND SILENCER..............4-3
RADIATOR..................................................4-4
CARBURETOR AND REED VALVE...........4-7
CYLINDER HEAD , CYLINDER AND
PISTON.....................................................4-17
CLUTCH AND PRIMARY DRIVEN
GEAR.......................................................4-30
KICK AXLE, SHIFT SHAFT AND
PRIMARY DRIVE GEAR...........................4-37
YPVS GOVERNOR...................................4-45
WATER PUMP..........................................4-48
CDI MAGNETO.........................................4-52
ENGINE REMOVAL..................................4-56
CRANKCASE AND CRANKSHAFT.........4-61
TRANSMISSION, SHIFT CAM AND
SHIFT FORK.............................................4-69
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL........5-1
FRONT BRAKE AND REAR BRAKE.......5-10
FRONT FORK...........................................5-26
HANDLEBAR............................................5-41
STEERING................................................5-48
SWINGARM..............................................5-53
REAR SHOCK ABSORBER.....................5-61
1C3-9-30-0 25/5/04 7:14 PM Page 20

1-2
GEN
INFO
MACHINE IDENTIFICATION
EC120001
MACHINE IDENTIFICATION
There are two significant reasons for knowing
the serial number of your machine:
1. When ordering parts, you can give the num-
ber to your Yamaha dealer for positive iden-
tification of the model you own.
2. If your machine is stolen, the authorities will
need the number to search for and identify
your machine.
EC121001
VEHICLE IDENTIFICATION NUMBER
(For USA, CDN, AUS, NZ and E)
The vehicle identification number 1is stamped
on the right of the steering head pipe.
EC122001
FRAME SERIAL NUMBER
(For F, D, GB, I and ZA)
The frame serial number 1is stamped on the
right of the steering head pipe.
EC123001
ENGINE SERIAL NUMBER
The engine serial number 1is stamped into the
elevated part of the right-side of the engine.
EC124000
MODEL LABEL
The model label 1is affixed to the frame under
the rider’s seat. This information will be needed
to order spare parts.
1C3-9-30-1A 17/5/04 1:08 PM Page 4

1-8
GEN
INFO
SPECIAL TOOLS
Part number Tool name / How to use IIIustration
YU-24460-01, 90890-01325Radiator cap testerYU-24460-01 90890-01325
YU-33984, 90890-01352 AdapterYU-33984 90890-01352
These tools are used for checking the cooling
system.
YU-33270-B, 90890-01362Flywheel puller
YU-33270-B 90890-01362
These tool is used to split the crankcase.
YU-33975, 90890-01403 Ring nut wrench
YU-33975 90890-01403
This tool is used when tighten the steering ring nut
to specification.
YM-01442, 90890-01442 Fork seal driver
YM-01442 90890-01442
This tool is used when install the fork oil seal.
YM-01500, 90890-01500 Cap bolt wrench
YM-01500 90890-01500
This tool is used to loosen or tighten the base valve.
YM-01501, 90890-01501 Cap bolt ring wrench
YM-01501 90890-01501
This tool is used to loosen or tighten the damper
assembly.
YU-3112-C, 90890-03112 Yamaha pocket tester
YU-3112-C 90890-03112
Use this tool to inspect the coil resistance,
output voltage and amperage.
YM-91042, 90890-04086 Clutch holding tool
YM-91042 90890-04086
This tool is used to hold the clutch when removing
or installing the clutch boss securing nut.
YM-34487 Dynamic spark tester
YM-34487 90890-06754
90890-06754 Ignition checker
This instrument is necessary for checking the igni-
tion system components.
ACC-QUICK-GS-KT Quick gasket
®ACC-QUICK-GS-KT 90890-85505
90890-85505 YAMAHA Bond No. 1215
This sealant (Bond) is used for crankcase mating
surface, etc.
1C3-9-30-1A 17/5/04 1:08 PM Page 15

1-16
GEN
INFO
TORQUE-CHECK POINTS
EC1A0013
TORQUE-CHECK POINTS
Frame construction Frame to rear frame
Combined seat and tank Fuel tank to frame
Engine mounting Frame to engine
Engine bracket to engine
Engine bracket to frame
Steering Steering shaft to Steering shaft to frame
handlebar Steering shaft to handle crown
Handle crown to handlebar
Suspension Front Steering shaft to Front fork to handle crown
front fork Front fork to under bracket
Rear For link type Assembly of links
Link to frame
Link to shock absorber
Link to swingarm
Rear Installation of shock Shock absorber to frame
absorber
Rear Installation of swingarm Tightening of pivot shaft
Wheel Installation of wheel Front Tightening of front axle
Tightening of axle holder
Rear Tightening of rear axle
Wheel to sprocket
Brake Front Caliper to front fork
Brake disc to wheel
Tightening of union bolt
Master cylinder to handlebar
Tightening of air bleeder
Tightening of brake hose holder
Rear Brake pedal to frame
Brake disc to wheel
Tighening of union bolt
Master cylinder to frame
Tightening of air bleeder
Tightening of brake hose holder
Fuel system Fuel tank to fuel cock
NOTE:
Concerning the tightening torque, refer to “
MAINTENANCE SPECIFICATIONS” section in
the CHAPTER 2.
1C3-9-30-1B 14/5/04 5:03 PM Page 10

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
465 mm (18.3 in)←460 mm (18.1 in)
Spring rate, STD K=4.1 N/mm K=4.0 N/mm…
(0.418 kg/mm, (0.408 kg/mm,
23.4 lb/in) 22.8 lb/in)
Optional spring/Spacer Yes←…
Oil capacity 430 cm
3435 cm3…
(15.1 Imp oz, (15.3 Imp oz,
14.5 US oz) 14.7 US oz)
Oil grade Suspension oil ←…
“S1”
Inner tube outer diameter 48 mm (1.89 in)←…
Front fork top end 5 mm (0.2 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)←…
Fitting length
252 mm (9.92 in)248 mm (9.76 in)…

240.5~258.5 mm←…
(9.47~10.18 in)
Spring rate, STD K=46.0 N/mm ←…
(4.70 kg/mm,
263.2 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)
1C3-9-30-2A 25/5/04 7:13 PM Page 8

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 damper assembly M51 ×1.5 2 30 3.0 22
Front fork and adjuster M22 ×1.25 2 55 5.5 40
Damper assembly and base valve M42 ×1.5 2 29 2.9 21
Adjuster and damper assembly M12 ×1.25 2 29 2.9 21
Bleed screw (front fork) and base valve 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 under bracketM 6 ×1.0 1 4 0.4 2.9
Protector and brake hose holder M 6 ×1.0 2 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 (nut) M 6 ×1.0 1 4 0.4 2.9
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
Front brake caliper and brake hose holder M 6 ×1.0 1 10 1.0 7.2
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 2 3 0.3 2.2
Brake caliper (front and rear) and pad pin M10 ×1.0 2 18 1.8 13
Brake caliper (front and rear) and bleed screwM 8 ×1.25 2 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
Footrest bracket and frame M10 ×1.25 4 55 5.5 40
Brake pedal mounting M 8 ×1.25 1 26 2.6 19


 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1C3-9-30-2A 25/5/04 7:13 PM Page 10

2-13
SPECCABLE ROUTING DIAGRAM
EC240000
CABLE ROUTING DIAGRAM
1Ground lead
2High tension cord
3Grommet
4Air vent hose
5Crankcase breather hose
6Y.P.V.S. breather hose
7Throttle cable
8Clutch cable
9Engine bracket (right)
0Engine bracket (left)
qAir vent hose (left)
wAir vent hose (right)
e“ENGINE STOP” button leadAPass the clutch cable on the
outside of the throttle cable and
“ENGINE STOP” button lead.
BInsert the tip of the fuel tank
breather hose into the hole in
the steering shaft cap.
CAlign the throttle cable locating
tape with the cable guide.
DPass through the cable guide
the throttle cable, “ENGINE
STOP” button lead and clutch
cable.
EPass the throttle cable and
clutch cable above the radiator
hose, and pass the “ENGINE
STOP” button lead below the
radiator hose.FInstall the ignition coil, side
core and ground lead together
to the frame.
GClamp the clutch cable to the
left engine bracket. Clamp the
clutch cable below the position-
ing grommet.
HPass the air vent hose back of
the throttle cable.
IPass the air vent hose, over-
flow hose and crankcase
breather hose between the
frame and connecting rod.
1C3-9-30-2B 27/5/04 4:18 PM Page 26

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 or
Replaceequivalent oil
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 “S1”
Replace oil seal
FRONT FORK OIL SEAL AND DUST SEAL
Clean and lubeLithium base grease
PROTECTOR GUIDE
Replace
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
1C3-9-30-3A 17/5/04 8:42 PM Page 3