brake YAMAHA YZ250F 2007 User Guide

2 - 26
SPECCABLE ROUTING DIAGRAM
1Throttle cable
2Clamp
3Hot starter cable
4Clutch cable
5Engine stop switch lead
6Cable guide
7Brake hose
8Hose guideÈFasten the engine stop switch lead to the handle-
bar.
ÉPass the clutch cable and hot starter cable
through the cable guide.
ÊPass the brake hose in front of the number plate.
ËPass the throttle cables through the cable guide.
ÌPass the clutch cable and hot starter cable
through the cable guide on the number plate.
A
B
C
A
B
C40˚± 10˚
40˚± 10˚
2
È3
2
5
4
2
3
5
6
Ë1
4
5
7
Ê
6
É
Ì
8

3 - 2
INSP
ADJ
MAINTENANCE INTERVALS
SHIFT FORK, SHIFT CAM, GUIDE BAR
InspectInspect wear
ROTOR NUT
Retighten
EXHAUST PIPE, SILENCER, PRO-
TECTOR
Inspect and retighten
Clean
Replace * Whichever comes first
CRANK
Inspect and clean
CARBURETOR
Inspect, adjust and clean
SPARK PLUG
Inspect and clean
Replace
DRIVE CHAIN
Use chain lube
Chain slack: 48 ~ 58 mm
(1.9 ~ 2.3 in) Lubricate, slack, alignment
Replace
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolant Every two years
Inspect hoses
OUTSIDE NUTS AND BOLTS Refer to “STARTING
AND BREAK-IN” section
in the CHAPTER 1. Retighten
AIR FILTER
Clean and lubricate
Use foam air-filter oil or
equivalent oil
Replace
OIL FILTER
Replace
OIL STRAINER
Clean
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 fluid Every one year
FRONT FORKS
Inspect and adjust
Replace oil Suspension oil “S1”
Replace oil sealItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)As re-
quiredRemarks


3

3 - 4
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
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.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator cap.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-13
Engine oilCheck that the oil level is correct. Check the crankcase and oil
line for leakage.P.3-13 ~ 17
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-9 ~ 10
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-10 ~ 11
Brakes Check the play of front brake and effect of front and rear brake. P.3-23 ~ 29
Drive chainCheck drive chain slack and alignment. Check that the drive
chain is lubricated properly.P.3-30 ~ 32
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-40 ~ 41
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-41 ~ 43
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-32 ~ 39
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or
when the front forks travel up and down.—
Exhaust pipeCheck that the exhaust pipe is tightly mounted and has no
cracks.P.4-3 ~ 5
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-30
Lubrication Check for smooth operation. Lubricate if necessary. P.3-44
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-18
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-6
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 21

3 - 23
INSP
ADJ
CHASSIS/BRAKE SYSTEM AIR BLEEDING
EC360000
CHASSIS
EC361012
BRAKE SYSTEM AIR BLEEDING
WARNING
Bleed the brake system if:
The system has been disassembled.
A brake hose has been loosened or
removed.
The brake fluid is very low.
The brake operation is faulty.
A dangerous loss of braking performance
may occur if the brake system is not prop-
erly bled.
1. Remove:
Brake master cylinder cap
Diaphragm
Reservoir float (front brake)
Protector (rear brake)
2. Bleed:
Brake fluid
È
Front
ÉRear
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 2 tightly
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
pedal. 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
release the lever or pedal.
T R..
Bleed screw:
6 Nm (0.6 m  kg, 4.3 ft  lb)
i. Repeat steps (e) to (h) until of the air
bubbles have been removed from the
system.
È
É

3 - 24
INSP
ADJ
FRONT BRAKE ADJUSTMENT
3. Install:
Protector (rear brake)
Reservoir float (front brake)
Diaphragm
Brake master cylinder cap
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 disap-
peared.
j. Add brake fluid to the level line on the
reservoir.
WARNING
Check the operation of the brake after
bleeding the brake system.
EC362040
FRONT BRAKE ADJUSTMENT
1. Check:
Brake lever position a
2. Remove:
Brake lever cover
3. Adjust:
Brake lever position
4. Install:
Brake lever cover
Brake lever position
a:
Standard position Extent of adjustment
95 mm (3.74 in)76 ~ 97 mm
(2.99 ~ 3.82 in)
Brake lever position adjustment steps:
Loosen the locknut 1.
Turn the adjusting bolt 2 until the lever
position a is within specified position.
Tighten the locknut.
T R..
Locknut:
5 Nm (0.5 m  kg, 3.6 ft  lb)
CAUTION:
Be sure to tighten the locknut, as it will
cause poor brake performance.

3 - 25
INSP
ADJREAR BRAKE ADJUSTMENT/
FRONT BRAKE PAD INSPECTION AND REPLACEMENT
EC364002
REAR BRAKE ADJUSTMENT
1. Check:
Brake pedal height a
Out of specification → Adjust.
Brake pedal height
a:
5 mm (0.20 in)
2. Adjust:
Brake pedal height
Pedal height adjustment steps:
Loosen the locknut 1.
Turn the adjusting nut 2 until the pedal
height a is within specified height.
Tighten the locknut.
WARNING
Adjust the pedal height between the
maximum
È and the minimum
É as
shown. (In this adjustment, the bolt
3
end
b should protrude out of the
threaded portion
4 but not be less than
2 mm (0.08 in)
c away from the brake
pedal
5).
After the pedal height adjustment, make
sure that the rear brake does not drag.
È
É
FRONT BRAKE PAD INSPECTION AND
REPLACEMENT
1. Inspect:
Brake pad thickness a
Out of specification → Replace as a set.
Brake pad thickness:
4.4 mm (0.17 in)
: 1.0 mm (0.04 in)
2. Replace:
Brake pad
Brake pad replacement steps:
Remove the pad pin plug 1.

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INSP
ADJ
FRONT BRAKE PAD INSPECTION AND REPLACEMENT
Loosen the pad pin 2.
Remove the brake caliper 3 from the front
fork.
Remove the pad pin and brake pads 4.
Connect the transparent hose 5 to the
bleed screw 6 and place the suitable con-
tainer under its end.
Loosen the bleed screw and push the
brake caliper piston in.
CAUTION:
Do not reuse the drained brake fluid.
Tighten the bleed screw.
T R..
Bleed screw:
6 Nm (0.6 m  kg, 4.3 ft  lb)
Install the brake pads 7 and pad pin.
NOTE:
Install the brake pads with their projections
a into the brake caliper recesses b.
Temporarily tighten the pad pin at this
point.
Install the brake caliper 8 and tighten the
pad pin 9.
T R..
Bolt (brake caliper):
23 Nm (2.3 m  kg, 17 ft  lb)
Pad pin:
18 Nm (1.8 m  kg, 13 ft  lb)

3 - 27
INSP
ADJ
REAR BRAKE PAD INSPECTION AND REPLACEMENT
3. Inspect:
Brake fluid level
Refer to “BRAKE FLUID LEVEL INSPEC-
TION” section. Install the pad pin plug 0.
T R..
Pad pin plug:
3 Nm (0.3 m  kg, 2.2 ft  lb)
4. Check:
Brake lever operation
A softy or spongy feeling → Bleed brake
system.
Refer to “BRAKE SYSTEM AIR BLEED-
ING” section.
REAR BRAKE PAD INSPECTION AND
REPLACEMENT
1. Inspect:
Brake pad thickness a
Out of specification → Replace as a set.
Brake pad thickness:
6.4 mm (0.25 in)
: 1.0 mm (0.04 in)
2. Replace:
Brake pad
Brake pad replacement steps:
Remove the protector 1 and pad pin plug
2.
Loosen the pad pin 3.
Remove the rear wheel 4 and brake cali-
per 5.
Refer to “FRONT WHEEL AND REAR
WHEEL” section in the CHAPTER 5.

3 - 28
INSP
ADJ
REAR BRAKE PAD INSPECTION AND REPLACEMENT
Remove the pad pin 6 and brake pads 7.
Connect the transparent hose 8 to the
bleed screw 9 and place the suitable con-
tainer under its end.
Loosen the bleed screw and push the
brake caliper piston in.
CAUTION:
Do not reuse the drained brake fluid.
Tighten the bleed screw.
T R..
Bleed screw:
6 Nm (0.6 m  kg, 4.3 ft  lb)
Install the brake pad 0 and pad pin A.
NOTE:
Install the brake pads with their projections
a into the brake caliper recesses b.
Temporarily tighten the pad pin at this
point.
Install the brake caliper B and rear wheel
C.
Refer to “FRONT WHEEL AND REAR
WHEEL” section in the CHAPTER 5.
Tighten the pad pin D.
T R..
Pad pin:
18 Nm (1.8 m  kg, 13 ft  lb)
Install the pad pin plug E and protector
F.
T R..
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 - 29
INSP
ADJREAR BRAKE PAD INSULATOR INSPECTION/
BRAKE FLUID LEVEL INSPECTION
3. Inspect:
Brake fluid level
Refer to “BRAKE FLUID LEVEL INSPEC-
TION” section.
4. Check:
Brake pedal operation
A softy or spongy feeling → Bleed brake
system.
Refer to “BRAKE SYSTEM AIR BLEED-
ING” section.
EC36b000
REAR BRAKE PAD INSULATOR
INSPECTION
1. Remove:
Brake pad
Refer to “REAR BRAKE PAD INSPEC-
TION AND REPLACEMENT” section.
2. Inspect:
Rear brake pad insulator 1
Damage → Replace.
BRAKE FLUID LEVEL INSPECTION
1. Place the brake master cylinder so that its
top is in a horizontal position.
2. Inspect:
Brake fluid level
Fluid at lower level → Fill up.
aLower level
ÈFront
ÉRear
WARNING
Use only designated quality brake fluid to
avoid poor brake performance.
Refill with same type and brand of brake
fluid; mixing fluids could result in poor
brake performance.
Be sure that water or other contaminants
do not enter master cylinder when refill-
ing.
Clean up spilled fluid immediately to
avoid erosion of painted surfaces or plas-
tic parts.
Recommended brake fluid:
DOT #4
ÈÉ