brake YAMAHA YZ125LC 2007 User Guide

2-17
SPECCABLE ROUTING DIAGRAM
AInstall the brake hose so that its pipe portion
directs as shown and lightly touches the projec-
tion on the master cylinder.
BPass the “ENGINE STOP” button lead in the
middle of the clutch holder.
CClamp the “ENGINE STOP” button lead to the
handlebar.
DPass the brake hose in front of the number
plate and through the cable guide.
EPass the clutch cable through the cable guide
on the number plate. 1Brake hose
2Master cylinder
3“ENGINE STOP” button lead
4“ENGINE STOP” button
5Throttle cable
6Clutch cable
7Clamp
8Cable guide
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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
Replace spring seatEvery one year
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
After
break-
inEvery
raceEvery
thirdEvery
fifthAs re-
quired
3
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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.P3-35~37
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. P3-38
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
P7-1~23
results of test runs before racing? Are inspection and
maintenance completely done?
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3-17
INSP
ADJ
CHASSIS/BRAKE SYSTEM AIR BLEEDING
EC360000
CHASSIS
EC361030
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 bled.
1. Remove:
9Master cylinder cap
9Diaphragm
9Reservoir float (front brake)
9Protector (rear brake)
2. Bleed:
9Brake fluid
ÅFront
ıRear
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 sev-
eral 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)
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3-18
INSP
ADJ
FRONT BRAKE ADJUSTMENT
3. Install:
9Protector (rear brake)
9Reservoir float (front brake)
9Diaphragm
9Master cylinder cap
EC362041
FRONT BRAKE ADJUSTMENT
1. Check:
9Brake lever position a
2. Remove:
9Lever cover
3. Adjust:
9Brake lever position
NOTE:
If bleeding is difficult, it may be necessary
to let the brake fluid system stabilize for a
few hours. Repeat the bleeding procedure
when the tiny bubbles in the system have
disappeared.
j. Add brake fluid to the level line on the
reservoir.
w
Check the operation of the brake after
bleeding the brake system.
Brake lever position a a
:
Standard position Extent of adjutment
95 mm (3.74 in)76 ~ 97 mm
(2.99 ~ 3.82 in)
Brake lever position adjustment steps:
9Loosen the locknut 1.
9Turn the adjusting bolt 2until the lever posi-
tion a is within specified position.
9Tighten the locknut.
cC
Be sure to tighten the locknut, as it will
cause poor brake performance.
Locknut:
5 Nm (0.5 m•kg, 3.6 ft•lb)
4. Install:
9Lever cover
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3-19
REAR BRAKE ADJUSTMENT/
FRONT BRAKE PAD INSPECTION AND REPLACEMENTINSP
ADJ
EC365080
FRONT BRAKE PAD INSPECTION AND
REPLACEMENT
1. Inspect:
9Brake pad thickness a
Out of specification Replace as a set.
2. Replace:
9Brake pad
Brake pad thickness a a
:
Standard
4.4 mm (0.17 in)
1.0 mm (0.04 in)
Brake pad replacement steps:
9Remove the pad pin plug 1.
EC364005
REAR BRAKE ADJUSTMENT
1. Check:
9Brake pedal height a
Out of specificationAdjust.
NOTE:
The brake pedal height is the vertical distance
from the inside top end of the footrest.
2. Adjust:
9Brake pedal height
Brake pedal height a a
:
Zero mm (Zero in)
Pedal height adjustment steps:
9Loosen the locknut 1.
9Turn the adjusting nut 2until the pedal
height ais within specified height.
9Tighten the locknut.
w
9Adjust the pedal height between the
maximum Å Å
and the minimum ı ı
as
shown. (In this adjustment, the bolt 3 3
end b b
should protrude out of the thread-
ed portion 4 4
but not be less than 2 mm
(0.08 in) c c
away from the brake pedal
5 5
).
9After the pedal height adjustment, make
sure that the rear brake does not drag.
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3-20
FRONT BRAKE PAD INSPECTION AND REPLACEMENT
INSP
ADJ
9Loosen the pad pin 2.
9Remove the caliper 3from the front fork.
9Remove the pad pin and brake pads 4.
9Connect the transparent hose 5to the
bleed screw 6and 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 7and pad pin.
NOTE:
9Install the brake pads with their projections
ainto the caliper recesses b.
9Temporarily tighten the pad pin at this point.
9Install the caliper 8and tighten the pad pin
9.
Bleed screw:
6 Nm (0.6 m•kg, 4.3 ft•b)
Bolt (caliper):
23 Nm (2.3 m•kg, 17 ft•lb)
Pad pin:
18 Nm (1.8 m•kg, 13 ft•lb)
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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 0.
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.
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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.
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3-23
REAR BRAKE PAD INSULATOR INSPECTION/
BRAKE FLUID LEVEL INSPECTIONINSP
ADJ
EC36b000
REAR BRAKE PAD INSULATOR
INSPECTION
1. Remove:
9Brake pad
Refer to
“REAR BRAKE PAD INSPEC-
TION AND REPLACEMENT” section.
2. Inspect:
9Rear brake pad insulator 1
Damage Replace.
EC367001
BRAKE FLUID LEVEL INSPECTION
1. Place the master cylinder so that its top is in
a horizontal position.
2. Inspect:
9Brake fluid level
Fluid at lower level Fill up.
aLower level
ÅFront
ıRear
w
9Use only designated quality brake fluid to
avoid poor brake performance.
9Refill with same type and brand of brake flu-
id; mixing fluids could result in poor brake
performance.
9Be sure that water or other contaminants do
not enter master cylinder when refilling.
9Clean up spilled fluid immediately to avoid
erosion of painted surfaces or plastic parts.
Recommended brake fluid:
DOT #4
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