Yamaha Wr250r 2008 Manual

							 
FRONT BRAKE 
4-21 
EAS22520 
ASSEMBLING THE FRONT BRAKE MASTER 
CYLINDER
WARNING
 
EWA13520  
 
Before installation, all internal brake com-
ponents should be cleaned and lubricated
with clean or new brake fluid. 
 
Never use solvents on internal brake com- 
ponents. 
1. Install: 
 
Master cylinder cup 
 
Master cylinder piston
2. Install: 
 
Circlip “1” 
 
Dust boot “2” 
EAS22530 
INSTALLING THE FRONT BRAKE MASTER 
CYLINDER 
1. Install: 
 
Brake master cylinder “1”
NOTE:
 
 
Install the brake master cylinder holder with the
“UP” mark facing up. 
 
Align the end of the brake master cylinder hold-
er with the punch mark “a” on the handlebar. 
 
First, tighten the upper bolt, then the lower bolt.2. Install: 
 
Copper washers “1”  
 
Brake hose “2” 
 
Union bolt “3”
WARNING
 
EWA13530  
Proper brake hose routing is essential to in-
sure safe vehicle operation. Refer to “CA- 
BLE ROUTING” on page 2-30.
NOTE:
 
 
While holding the brake hose, tighten the union
bolt as shown. 
 
Turn the handlebar to the left and right to make
sure the brake hose does not touch other parts
(e.g., wire harness, cables, leads). Correct if 
necessary.
3. Fill: 
 
Brake master cylinder reservoir
(with the specified amount of the recom-
mended brake fluid)
WARNING
 
EWA13540  
 
Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor Recommended fluid
DOT 4
Brake master cylinder holder bolt
7 Nm (0.7 m•kg, 5.1 ft•lb)
New
New
TR..
 
Brake hose union bolt
30 Nm (30. m•kg, 22 ft•lb)
Recommended fluid
DOT 4
a
1
New
TR..
1
2
3New 
						

							 
FRONT BRAKE 
4-22 
brake performance. 
 
Refill with the same type of brake fluid that
is already in the system. Mixing brake flu-
ids may result in a harmful chemical reac-
tion, leading to poor brake performance. 
 
When refilling, be careful that water does
not enter the brake master cylinder reser-
voir. Water will significantly lower the boil-
ing point of the brake fluid and could cause 
vapor lock.
CAUTION:
 
 ECA13540 
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean up 
any spilt brake fluid immediately. 
4. Bleed: 
 
Brake system
Refer to “BLEEDING THE HYDRAULIC
BRAKE SYSTEM” on page 1-25.
5. Check: 
 
Brake fluid level
Below the minimum level mark  
→ 
 Add the
recommended brake fluid to the proper level.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 1-23.
6. Check: 
 
Brake lever free play
Refer to “ADJUSTING THE FRONT DISC
BRAKE” on page 1-22. 
 
Brake lever operation
Soft or spongy feeling  
→ 
 Bleed the brake
system.
Refer to “BLEEDING THE HYDRAULIC
BRAKE SYSTEM” on page 1-25. 
						

							 
REAR BRAKE 
4-23 
EAS22550 
REAR BRAKE 
Removing the rear brake pads
Order Job/Parts to remove Q’ty Remarks  
Rear wheel Refer to“REAR WHEEL” on page 4-7.
1 Protector 1
2 Pin plug 1
3 Brake pad support bolt 1
4 Rear brake pad 2
5 Pad shim 2
6 Insulator 2
7 Rear brake pad spring 1
8 Rear brake caliper assembly 1
For installation, reverse the removal proce-
dure.
1 2 3
4 5
5 6
6 7 8
T R..7 Nm (0.7 m • kg, 5.1 ft • Ib) 
T R..17 Nm (1.7 m • kg, 12 ft • Ib) 
T R..2.5 Nm (0.25 m • kg, 1.8 ft • Ib)  
						

							 
REAR BRAKE 
4-24 
Removing the rear brake master cylinder
Order Job/Parts to remove Q’ty Remarks  
Brake fluidDrain.
Refer to “BLEEDING THE HYDRAULIC 
BRAKE SYSTEM” on page 1-25.
1 Union bolt 1
2 Copper washer 2
3 Brake hose 1
4 Split pin 1
5 Plain washer 1
6 Pin 1
7 Brake master cylinder reservoir cap 1
8 Brake master cylinder reservoir diaphragm plate 1
9 Brake master cylinder reservoir diaphragm 1
10 Rear brake master cylinder 1
For installation, reverse the removal proce-
dure.
1
2
3
4 7
5 8
6 9
10
T R..10 Nm (1.0 m • kg, 7.2 ft • Ib) 
T R..30 Nm (3.0 m • kg, 22 ft • Ib)  
						

							 
REAR BRAKE 
4-25 
Disassembling the rear brake master cylinder
Order Job/Parts to remove Q’ty Remarks  
1 Master cylinder kit 1
For assembly, reverse the disassembly pro-
cedure.
S1
T R..12 Nm (1.2 m • kg, 8.7 ft • Ib)  
						

							 
REAR BRAKE 
4-26 
Removing the rear brake calipers
Order Job/Parts to remove Q’ty Remarks  
Brake fluidDrain.
Refer to“BLEEDING THE HYDRAULIC 
BRAKE SYSTEM” on page 1-25.
Protector Refer to“REAR BRAKE” on page 4-23.
1 Union bolt 1
2 Copper washer 2
3 Rear brake hose 1
4 Pin plug 1
5 Brake caliper support bolt 1
6 Rear brake pad assemblyl 2
7 Rear brake caliper bracket 1
8 Brake pad spring 2
9 Rear brake caliper assembly 1
For installation, reverse the removal proce-
dure.
1
2
3
45
6 78
89
S
T R..30 Nm (3.0 m • kg, 22 ft • Ib) 
T R..17 Nm (1.7 m • kg, 12 ft • Ib) 
T R..2.5 Nm (0.25 m • kg, 1.8 ft • Ib)  
						

							 
REAR BRAKE 
4-27 
Disassembling the rear brake calipers
Order Job/Parts to remove Q’ty Remarks  
1 Brake caliper piston 1
2 Brake caliper dust seal 1
3 Brake caliper piston seal 1
4 Bleed screw 1
For assembly, reverse the disassembly pro-
cedure.
1
2
3
4
S
BF
T R..6 Nm (0.6 m • kg, 4.3 ft • Ib)  
						

							 
REAR BRAKE 
4-28 
EAS22560 
INTRODUCTION
WARNING
 
EWA14100  
Disc brake components rarely require disas-
sembly. Therefore, always follow these pre-
ventive measures: 
 
Never disassemble brake components un-
less absolutely necessary. 
 
If any connection on the hydraulic brake
system is disconnected, the entire brake
system must be disassembled, drained,
cleaned, properly filled, and bled after reas-
sembly. 
 
Never use solvents on internal brake com-
ponents. 
 
Use only clean or new brake fluid for clean-
ing brake components. 
 
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately. 
 
Avoid brake fluid coming into contact with
the eyes as it can cause serious injury. 
 
FIRST AID FOR BRAKE FLUID ENTERING
THE EYES: 
 
Flush with water for 15 minutes and get im- 
mediate medical attention. 
EAS22570 
CHECKING THE REAR BRAKE DISC 
1. Remove: 
 
Rear wheel
Refer to “REAR WHEEL” on page 4-7.
2. Check: 
 
Brake disc
Damage/galling  
→ 
 Replace.
3. Measure: 
 
Brake disc deflection
Out of specification  
→ 
 Correct the brake disc
deflection or replace the brake disc.
Refer to “CHECKING THE FRONT BRAKE
DISC” on page 4-16.
4. Measure: 
 
Brake disc thickness
Measure the brake disc thickness at a few dif-
ferent locations.
Out of specification  
→ 
 Replace.
Refer to “CHECKING THE FRONT BRAKE
DISC” on page 4-16.5. Adjust: 
 
Brake disc deflection
Refer to “CHECKING THE FRONT BRAKE
DISC” on page 4-16.
6. Install: 
 
Rear wheel
Refer to “REAR WHEEL” on page 4-7. 
EAS22580 
REPLACING THE REAR BRAKE PADS
NOTE:
 
When replacing the brake pads, it is not neces-
sary to disconnect the brake hose or disassem- 
ble the brake caliper.
1. Measure: 
 
Brake pad wear limit “a”
Out of specification  
→  
 Replace the brake
pads as a set.
2. Install: 
 
Brake pad shims
(onto the brake pads) 
 
Brake pads 
 
Brake pad spring
NOTE:
 
Always install new brake pads, brake pad shims, 
Brake disc deflection limit
0.15 mm (0.0059 in) 
Brake disc thickness limit
4.0 mm (0.16 in)
Brake disc bolt
12 Nm (1.2 m•kg, 8.7 ft•lb)
LOCTITE®
Brake pad lining thickness (inner)
6.4 mm (0.25 in)
Limit
1.0 mm (0.04 in)
Brake pad lining thickness (outer)
6.4 mm (0.25 in)
Limit
1.0 mm (0.04 in)
TR..
a 
						

							 
REAR BRAKE 
4-29 
and a brake pad spring as a set.

 
a. Connect a clear plastic hose “1” tightly to the
bleed screw “2”. Put the other end of the hose
into an open container.
b. Loosen the bleed screw and push the brake
caliper pistons into the brake caliper with your
finger.
c. Tighten the bleed screw.
d. Install a new brake pad shim onto each new
brake pad.
e. Install new brake pads and a new brake pad
spring.
NOTE:
 
The longer tangs “b” of the brake pad spring 
must point in the direction of disc rotation.

 
3. Install: 
 
Brake caliper support bolt 
 
Pin plug 
 
Rear brake caliper protector
4. Check: 
 
Brake fluid level
Below the minimum level mark “a”  
→ 
 Add the
recommended brake fluid to the proper level.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 1-23.5. Check: 
 
Brake pedal operation
Soft or spongy feeling   
→  
 Bleed the brake
system.
Refer to “BLEEDING THE HYDRAULIC
BRAKE SYSTEM” on page 1-25. 
EAS22590 
REMOVING THE REAR BRAKE CALIPER
NOTE:
 
Before disassembling the brake caliper, drain 
the brake fluid from the entire brake system.
1. Remove: 
 
Union bolt 
 
Copper washers 
 
Brake hose
NOTE:
 
Put the end of the brake hose into a container 
and pump out the brake fluid carefully. 
EAS22600 
DISASSEMBLING THE REAR BRAKE 
CALIPER 
1. Remove: 
 
Brake caliper piston “1” 
 
Brake caliper dust seals “2” 
 
Brake caliper piston seals “3”

 
a. Blow compressed air into the brake hose joint
opening to force out the piston from the brake
caliper. 
Bleed screw
6 Nm (0.6 m•kg, 4.3 ft•lb)
Brake caliper support bolt
17 Nm (1.7 m•kg, 12 ft•lb)
Pin plug
2.5 Nm (0.25 m•kg, 1.8 ft•lb)
Rear brake caliper protector
7 Nm (0.7 m•kg, 5.1 ft•lb)
2
1
TR..
TR..
a
2
3
1 
						

							 
REAR BRAKE 
4-30
WARNING
 
EWA13550  
 
Cover the brake caliper piston with a rag.
Be careful not to get injured when the pis-
ton is expelled from the brake caliper. 
 
Never try to pry out the brake caliper pis- 
ton. 
b. Remove the brake caliper dust seals brake
caliper piston seals.

 
EAS22640 
CHECKING THE REAR BRAKE CALIPER 
1. Check: 
 
Brake caliper pistons “1”
Rust/scratches/wear  
→ 
 Replace the brake
caliper pistons. 
 
Brake caliper cylinders “2”
Scratches/wear  
→ 
 Replace the brake caliper
assembly. 
 
Brake caliper body “3”
Cracks/damage  
→ 
 Replace the brake caliper
assembly. 
 
Brake fluid delivery passages
(brake caliper body)
Obstruction  
→ 
 Blow out with compressed air.
WARNING
 
EWA13610  
Whenever a brake caliper is disassembled, 
replace the brake caliper piston seals. 
2. Check: 
 
Brake caliper brackets
Cracks/damage  
→  
 Replace. 
EAS22650 
ASSEMBLING THE REAR BRAKE CALIPER
WARNING
 
EWA13620  
 
Before installation, all internal brake com-
ponents should be cleaned and lubricated
with clean or new brake fluid. 
 
Never use solvents on internal brake com-
ponents as they will cause the piston seals
to swell and distort. 
 
Whenever a brake caliper is disassembled, 
replace the brake caliper piston seals. 
EAS22670 
INSTALLING THE REAR BRAKE CALIPER 
1. Install: 
 
Rear brake caliper 
 
Rear brake caliper bracket
2. Install: 
 
Rear wheel
Refer to “REAR WHEEL” on page 4-7. 
 
Brake hose 
 
Union bolt
WARNING
 
EWA13530  
Proper brake hose routing is essential to in-
sure safe vehicle operation. Refer to “CA- 
Recommended brake component
replacement schedule 
Brake pads If necessary
Piston seals Every two years
Brake hoses Every four years
Brake fluidEvery two years and 
whenever the brake is dis-
assembled 
Recommended fluid
DOT 4
Union bolt
30 Nm (30. m•kg, 22 ft•lb)
1 2
3
TR..