2001 YAMAHA YZ125LC brake

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
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5MV-9-30-2A 6/19/00 1:15 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 ´–4 4 0.4 2.9
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 5 0.5 3.6
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 8 3 0.3 2.2
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 4 7 0.7 5.1
Seat mounting M 6 ´1.0 2 7 0.7 5.1
Number plate M 6 ´1.0 1 7 0.7 5.1
NOTE:
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s- marked portion shall be checked for torque tightening after break-in or before each race.
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5MV-9-30-2A 6/19/00 1:15 PM Page 11

2-13
SPECCABLE ROUTING DIAGRAM
EC240000
1Brake hose
2Fuel tank breather hose
3Cable guide
4Clamp
5“ENGINE STOP” button lead
6Throttle cable
7Air vent hose (right)
8Air vent hose (left)
9Transmission oil breather
hose
0Overflow hose
qRadiator breather hose
wCDI magneto lead
eYPVS breather hose
APass the fuel tank breather
hose between the handlebar
and tension bar, then insert
its end into the hole of the
number plate.
BPass the throttle cable and
“ENGINE STOP” button lead
into the cable guide. Align
with the cable guide the
front end of the tape on the
throttle cable.CClamp the throttle cable and
“ENGINE STOP” button lead
to the frame. With the clamp
ends downward, tighten the
throttle cable to the extent
that it moves smoothly.
DClamp the “ENGINE STOP”
button lead (where there is
no protector), wireharness and
throttle cable all together to the
frame. With the clamp ends
downward, pass the
wireharness on the outer side
of the chassis in relation to the
“ENGINE STOP” button lead.
EPass the air vent hose at
the rear of the throttle cable.
FPass the transmission oil
breather hose, air vent hoses
and overflow hose between
the frame and connecting rod.
GPass the radiator breather
hose and YPVS breather hose
outside the engine bracket
and inside the frame. Then
pass the radiator breather hose inside the YPVS
breather hose.
HClamp the radiater breather
hose and CDI magneto lead
on the rear of the down-tube.
IPass the radiater breather
hose and CDI magneto
lead between the frame and
radiator.
JAlign the top of the brake hose
neck with the brake hose
holder bottom.
KPass 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).
LFit the brake hose into the
guide on the protector.
MPass the throttle cable and
“ENGINE STOP” button lead
over the radiator hose.
NTighten the clamp with its
ends sideways as shown.
5MV-9-30-2B 6/19/00 1:14 PM Page 26

2-14
SPECCABLE ROUTING DIAGRAM
1Brake hose holder
2Master cylinder
3Brake hose
4Hose guide
5CDI unit band
6CDI unit
7High tension cord
8Ignition coil
9Cable guide
0Radiator breather hose
qWireharness
w“ENGINE STOP” button lead
eCDI magneto lead
rClutch cable
tClamp
yCDI unit bracket
uEngine bracket
iCDI unit damper
APass the brake hose into
the brake hose holder.BIf the brake hose contacts
the spring (rear shock
absorber), correct its twist.
CInstall the brake hose so that
its pipe portion directs as
shown and lightly touches
the projection on the master
cylinder.
DPass the reservoir hose
between the brake hose and
swingarm bracket.
EPut the CDI unit fully in
the CDI unit band.
FFasten the ground lead
together with the ignition
coil.
GPass the cluch cable into
the cable guide.
HClamp the CDI magneto lead
on the upper part of
the frame gusset at its
protecting tube.IPass the clutch cable over
the radiator hose.
JClamp the wireharness on
the top of the CDI unit with
the clamp end downward.
KCut the clamp end to be flush
with CDI unit side.
LFit the CDI unit band over
the CDI unit bracket till it
stops.
MInstall the brake hose to
the caliper with the paint on
the pipe facing the caliper
and with the pipe contacting
the caliper projection.
NPass the radiator breather
hose between the frame and
radiator hose so that it is not
kinked or wedged.
OPosition the CDI unit between
the engine brackets as
shown.
5MV-9-30-2B 6/19/00 1:14 PM Page 28

2-15
SPECCABLE ROUTING DIAGRAM
AInstall the brake hose so that its pipe portion
directs as show and lightly touches the
projection on the master cylinder.
BPass the “ENGINE STOP” button lead in
the middle of the clutch holder.
CPass the clutch cable in front of the throttle
cable.
DClamp the “ENGINE STOP” button lead to
the handlebar to 3 clicks.
EPass the brake hose in front of the number
plate and through the cable guide.
FCross the clutch cable and throttle cable
over the number plate boss. 1Brake hose
2Master cylinder
3“ENGINE STOP” button lead
4“ENGINE STOP” button
5Throttle cable
6Clutch cable
7Clamp
8Cable guide
5MV-9-30-2B 6/19/00 1:14 PM Page 30

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
5MV-9-30-3A 6/19/00 1:52 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?
5MV-9-30-3A 6/19/00 1:52 PM Page 14

3-17
INSP
ADJ
CHASSIS/BRAKE SYSTEM AIR BLEEDING
EC360000
CHASSIS
EC361012
BRAKE SYSTEM AIR BLEEDING
w
Bleed the brake system if:
9The system has been disassembled.
9A brake hose has been loosened or removed.
9The brake fluid is very low.
9The brake operation is faulty.
A dangerous loss of braking performance may
occur if the brake system is not properly
bleed.
1. Remove:
9Master cylinder cap
9Diaphragm
9Protector (rear brake)
2. Bleed:
9Brake fluid
Front
Air bleeding steps:
a. Add proper brake fluid to the reservoir.
b. Install the diaphragm. Be careful not to
spill any fluid or allow the reservoir to
overflow.
c. Connect the clear plastic tube 2tightly to
the caliper bleed screw 1.
d. Place the other end of the tube into a
container.
e. Slowly apply the brake lever or pedal
several times.
f. Pull the lever in or push down on the ped-
al. Hold the lever or pedal in position.
g. Loosen the bleed screw and allow the
lever or pedal to travel towards its limit.
h. Tighten the bleed screw when the lever
or pedal limit has been reached; then re-
lease the lever or pedal.
i. Repeat steps (e) to (h) until of the air
bubbles have been removed from the
system.
Bleed screw:
6 Nm (0.6 m•kg, 4.3 ft•lb)
5MV-9-30-3A 6/19/00 1:52 PM Page 42