2001 YAMAHA YZ125LC check oil

EC083000
MANUAL FORMAT
All of the procedures in this manual are organized in a sequential, step-by-step format. The informa-
tion has been complied to provide the mechanic with an easy to read, handy reference that contains
comprehensive explanations of all disassembly, repair, assembly, and inspection operations.
In this revised format, the condition of a faulty component will precede an arrow symbol and the
course of action required will follow the symbol, e.g.,
9Bearings
Pitting/DamageÕReplace.
EC084002
HOW TO READ DESCRIPTIONS
To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each re-
moval and disassembly section.
1. An easy-to-see exploded diagram 1is provided for removal and disassembly jobs.
2. Numbers 2are given in the order of the jobs in the exploded diagram. A number that is enclosed
by a circle indicates a disassembly step.
3. An explanation of jobs and notes is presented in an easy-to-read way by the use of symbol marks
3. The meanings of the symbol marks are given on the next page.
4. A job instruction chart 4accompanies the exploded diagram, providing the order of jobs, names
of parts, notes in jobs, etc.
5. Extent of removal 5is provided in the job instruction chart to save the trouble of an unnecessary
removal job.
6. For jobs requiring more information, the step-by-step format supplements 6are given in addition
to the exploded diagram and job instruction chart.
4-30
ENGCLUTCH AND PRIMARY DRIVEN GEAR
Extent of removal Order Part name Q’ty Remarks
CLUTCH PLATE AND
FRICTION PLATE REMOVAL
Preparation for Drain the transmission oil.
Refer to “TRANSMISSION OIL REPLACE-removalMENT“ section in the CHAPTER 3.Bolt (brake pedal) Shift the brake pedal downward.
Clutch cable Disconnect at engine side.
1 Clutch cover 1
2 Screw (clutch spring) 5
3 Clutch spring 5
4 Pressure plate 1
5 Push rod 1
6 Plain washer 2
7 Bearing 1
8 Friction plate 8
9 Clutch plate 7
Extent of removal:1Clutch plate and friction plate removal
EC490000CLUTCH AND PRIMARY DRIVEN GEAREC498000CLUTCH PLATE AND FRICTION PLATE
1
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
4-32
ENGCLUTCH AND PRIMARY DRIVEN GEAREC493000REMOVAL POINTSEC483211Clutch boss1. Remove:
9Nut 1
9Lock washer 2
9Clutch boss 3
NOTE:Straighten the lock washer tab and use the
clutch holding tool 4, 5to hold the clutch boss.
Œ
For USA and CDN
º
Except for USA and CDN
EC494000INSPECTIONEC484100Clutch housing and boss1. Inspect:
9Clutch housing 1
Cracks/Wear/Damage Õ Replace.
9Clutch boss 2
Scoring/Wear/Damage ÕReplace.
EC484201Primary driven gear1. Check:
9Circumferential play
Free play exists ÕReplace.
9Gear teeth a
Wear/ Damage ÕReplace.
EC484400Clutch spring1. Measure:
9Clutch spring free length a
Out of specification ÕReplace springs as
a set.
Clutch holding tool:
YM-91042................................4 4
90890-04086............................5 5
Clutch spring free length:
Standard
40.1 mm 38.1 mm
(1.579 in) (1.500 in)
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56
5MV-9-30-0 6/19/00 2:05 PM Page 12

EC0A0000
CONTENTS
CHAPTER 1
GENERAL INFORMATION
DESCRIPTION............................................1-1
MACHINE IDENTIFICATION......................1-2
IMPORTANT INFORMATION.....................1-3
CHECKING OF CONNECTION..................1-6
SPECIAL TOOLS........................................1-7
CONTROL FUNCTIONS.............................1-9
FUEL AND ENGINE MIXING OIL.............1-12
STARTING AND BREAK-IN.....................1-13
TORQUE-CHECK POINTS.......................1-16
CLEANING AND STORAGE....................1-17
CHAPTER 2
SPECIFICATIONS
GENERAL SPECIFICATIONS....................2-1
MAINTENANCE SPECIFICATIONS...........2-3
GENERAL TORQUE SPECIFICATIONS..2-12
DEFINITION OF UNITS............................2-12
CABLE ROUTING DIAGRAM..................2-13
CHAPTER 3
REGULAR INSPECTION
AND ADJUSTMENTS
MAINTENANCE INTERVALS.....................3-1
PRE-OPERATION INSPECTION AND
MAINTENANCE..........................................3-4
ENGINE.......................................................3-5
CHASSIS...................................................3-17
ELECTRICAL............................................3-38
5MV-9-30-0 6/19/00 2:05 PM Page 18

1-1
GEN
INFO
DESCRIPTION
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
1Clutch lever
2”ENGINE STOP” button
3Front brake lever
4Throttle grip
5Radiator cap
6Fuel tank cap
7Kick starter
8Fuel tank
9Radiator
0Coolant drain bolt
qCheck bolt (Transmission oil level)
wRear brake pedal
eValve joint
rFuel cock
tAir cleaner
yDrive chain
uShift pedal
iStarter knob
oFront fork
NOTE:
9The machine you have purchased may differ
slightly from those shown in the following.
9Designs and specifications are subject to
change without notice.
1
5MV-9-30-1A 6/19/00 1:11 PM Page 2

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-33975, 90890-01403 Ring nut wrench
YU-33975 90890-01403
This tool is used when tighten the steering ring nut
to specification.
YM-1423, 90890-01423 Damper rod holder
YM-1423 90890-01423
Use this tool to remove and install the damper rod.
YM-01442, 90890-01442 Fork seal driver
YM-01442 90890-01442
This tool is used when install the fork oil seal.
YU-3112-C, Yamaha pocket tester
YU-3112-C 90890-03112
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.
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1-14
GEN
INFO
STARTING AND BREAK-IN
EC194001
BREAK-IN PROCEDURES
1. Before starting the engine, fill the fuel tank
with a break-in oil-fuel mixture as follows.
2. Perform the pre-operation checks on the
machine.
3. Start and warm up the engine. Check the
idle speed, and check the operation of the
controls and the “ENGINE STOP” button.
4. Operate the machine in the lower gears at
moderate throttle openings for five to eight
minutes. Stop and check the spark plug con-
dition; it will show a rich condition during
break-in.
5. Allow the engine to cool. Restart the engine
and operate the machine as in the step
above for five minutes. Then, very briefly
shift to the higher gears and check full-throt-
tle response. Stop and check the spark
plug.
6. After again allowing the engine to cool,
restart and run the machine for five more
minutes. Full throttle and the higher gears
may be used, but sustained full-throttle op-
eration should be avoided. Check the spark
plug condition.
7. Allow the engine to cool, remove the top
end, and inspect the piston and cylinder.
Remove any high spots on the piston with
#600 grit wet sandpaper. Clean all compo-
nents and carefully reassemble the top end.
8. Drain the break-in oil-fuel mixture from the
fuel tank and refill with the specified mix.
9. Restart the engine and check the operation
of the machine throughout its entire operat-
ing range. Stop and check the spark plug
condition. Restart the machine and operate
it for about 10 to 15 more minutes. The ma-
chine will now be ready to race.
Mixing oil: Mixing ratio:
Yamalube “2-R” 15:1
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2-5
SPECMAINTENANCE SPECIFICATIONS
Part to be tightened Thread size Q'tyT ightening torqueNm m•kg ft•lb
Spark plug M14 ´1.25 1 20 2.0 14
Cylinder head (nut) M 8 ´1.25 5 28 2.8 20
(stud) M 8 ´1.25 5 13 1.3 9.4
Cylinder (nut) M 8 ´1.25 4 30 3.0 22
(stud) M10 ´1.25 4 13 1.3 9.4
Power valve:
Cover M 5 ´0.8 4 4 0.4 2.9
Link lever M 4 ´0.7 1 4 0.4 2.9
Holder (power valve) M 5 ´0.8 4 8 0.8 5.8
Push rod M 5 ´0.8 1 5 0.5 3.6
Thrust plate M 5 ´0.8 1 4 0.4 2.9
Governor fork M 4 ´0.7 2 5 0.5 3.6
Housing M 5 ´0.8 4 5 0.5 3.6
Impeller M 8 ´1.25 1 14 1.4 10
Water pump housing cover M 6 ´1.0 4 10 1.0 7.2
Coolant drain bolt M 6 ´1.0 1 10 1.0 7.2
Radiator hose clamp M 6 ´1.0 8 1 0.1 0.7
Air filter element M 6 ´1.0 1 2 0.2 1.4
Carburetor joint M 6 ´1.0 4 10 1.0 7.2
Air filter case M 6 ´1.0 2 4 0.4 2.9
Air filter joint M 5 ´0.8 5 1 0.1 0.7
Read valve M 3 ´0.5 6 1 0.1 0.7
Crankcase M 6 ´1.0 12 14 1.4 10
Crankcase cover (right) M 6 ´1.0 8 10 1.0 7.2
Crankcase cover (left) M 6 ´1.0 5 5 0.5 3.6
Chain cover M 6 ´1.0 2 5 0.5 3.6
Bearing plate cover M 6 ´1.0 3 10 1.0 7.2
Holder M 6 ´1.0 1 10 1.0 7.2
Oil check bolt M 6 ´1.0 1 10 1.0 7.2
Oil drain bolt M12 ´1.5 1 20 2.0 14
Kick starter M 6 ´1.0 1 10 1.0 7.2
Cluch cover M 6 ´1.0 6 10 1.0 7.2
Primary drive gear M10 ´1.25 1 55 5.5 40
Clutch boss M16 ´1.0 1 80 8.0 58
Clutch spring M 6 ´1.0 5 10 1.0 7.2
Push lever axle M 6 ´1.0 1 7 0.7 5.1
Drive sprocket M16 ´1.0 1 60 6.0 43
Shift pedal M 6 ´1.0 1 10 1.0 7.2
Bearing plate cover (shift cam) M 6 ´1.0 2 10 1.0 7.2
Shift guide M 6 ´1.0 2 10 1.0 7.2
Stopper lever M 6 ´1.0 1 10 1.0 7.2
Segment M 8 ´1.25 1 30 3.0 22
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3-1
MAINTENANCE INTERVALS
INSP
ADJ
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
EC310051
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 cleanllInspect crack
ReplacellRemove carbon
PISTON RING
InspectllCheck ring end gap
Replacell
PISTON PIN, SMALL END BEARING
Inspectl
Replacel
CYLINDER HEAD
Inspect and cleanllRemove carbon
RetightenllCheck gasket
CYLINDER
Inspect and cleanll
lInspect score marks
ReplaceInspect wear
YPVS
Inspect and cleanll
CLUTCHInspect housing, friction
Inspect and adjustllplate, clutch plate and
Replacelspring
TRANSMISSION
Replace oilllYamalube 4 (10W-30) or
InspectlSAE 10W-30 SE motor oil
Replace bearingl
SHIFT FORK, SHIFT CAM, GUIDE BAR
InspectlInspect wear
ROTOR NUT
Retightenll
MUFFLER
Inspectll
Cleanl
CRANK
Inspect and cleanll
CARBURETOR
Inspect, adjust and cleanll
SPARK PLUG
Inspect and cleanll
Replacel
DRIVE CHAIN Use chain lube
Lubricate, slack, alignmentllChain slack: 40~50 mm
Replacel(1.6~2.0 in)
After
break-
inEvery
raceEvery
thirdEvery
fifthAs re-
quired
3
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3-2
MAINTENANCE INTERVALS
INSP
ADJ
Item Remarks
COOLING SYSTEM
Check coolant level and leakagell
Check radiator cap operationl
Replace coolantlEvery two years
Inspect hosesl
OUTSIDE NUTS AND BOLTS Refer to “STARTING
RetightenllAND BREAK-IN” section
in the CHAPTER 1.
AIR FILTER
Clean and lubricatellUse foam air-filter oil
Replacel
FRAME
Clean and inspectll
FUEL TANK, COCK
Clean and inspectll
BRAKES
Adjust lever position and pedal heightll
Lubricate pivot pointll
Check brake disc surfacell
Check fluid level and leakagell
Retighten brake disc bolts, caliper bolts,
ll
master cylinder bolts and union bolts
Replace padsl
Replace brake fluidlEvery one year
FRONT FORKS
Inspect and adjustll
Replace oilllSuspension oil “01”
Replace oil seall
FRONT FORK OIL SEAL AND DUST SEAL
Clean and lubellLithium base grease
REAR SHOCK ABSORBER
Inspect and adjustll
Lube ll
Molybdenum disulfide grease
Retightenll
CHAIN GUARD AND ROLLERS
Inspectll
SWINGARM
Inspect and retightenll
RELAY ARM, CONNECTING ROD
Inspect and lubellMolybdenum disulfide grease
STEERING HEAD
Inspect free play and retightenll
Clean and lubelLithium base grease
Replace bearingl
TIRE, WHEELS
Inspect air pressure, wheel run-out,
ll
tire wear and spoke looseness
Retighten sprocket boltll
Inspect bearingsl
Replace bearingsl
LubricatelLithium base grease
THROTTLE, CONTROL CABLE
Check routing and connectionllYamaha cable lube or
LubricatellSAE 10W-30 motor oil
After
break-
inEvery
raceEvery
thirdEvery
fifthAs re-
quired
3
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