2015 YAMAHA WR 250F Owners Manual

REAR WHEEL
5-11
TIP
Tighten the self-locking nuts in stages and in a
crisscross pattern.
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EAS2GB2167ASSEMBLING THE REAR WHEEL
1. Install:
• Bearing (right side) “1”
• Circlip “2”
• Spacer “3”
• Bearing (left side) “4”
• Oil seals “5”
TIP
• Apply the lithium-soap-based grease to the
bearing and the oil seal lip when installing.
• Install the bearing with seal facing outward.
• Right side of bearing shall be installed first.
• Install the oil seal with its manufacture’s
marks or numbers facing outward.
ECA
NOTICE
Install the bearing by pressing its outer race
parallel.
TIP
Use a socket “1” that matches the diameter of
the bearing outer race and that of the oil seal.2. Install:
• Brake disc “1”
• Brake disc bolt “2”
TIP
Tighten the bolts in stages and in a crisscross
pattern.
3. Install:
• Collar “1”
TIP
Apply the lithium-soap-based grease on the oil
seal lip.
EAS2GB2168INSTALLING THE REAR WHEEL
1. Install:
• Rear wheel
New
New
5
43 1
25
LSLS
Brake disc bolt
14 Nm (1.4 m·kgf, 10 ft·lbf)
LOCTITE®
1
T R..
1
LS

REAR WHEEL
5-12
TIP
Install the brake disc “1” between the brake
pads “2” correctly.
2. Install:
• Drive chain “1”
TIP
Push the rear wheel “2” forward and install the
drive chain.
3. Install:
• Left drive chain puller “1”
• Rear wheel axle “2”
TIP
• Install the left drive chain puller, and insert the
rear wheel axle from the left side.
• Apply the lithium-soap-based grease to the
rear wheel axle.
4. Install:
• Right drive chain puller “1”
• Washer “2”
• Rear wheel axle nut “3”
TIP
Temporarily tighten the nut (rear wheel axle) at
this point.
5. Adjust:
• Drive chain slack “a”
Refer to “ADJUSTING THE DRIVE CHAIN
SLACK” on page 3-30.
6. Tighten:
• Rear wheel axle nut “1”
• Locknut “2”
Drive chain slack
50–60 mm (1.97–2.36 in)
Wheel axle nut
125 Nm (12.5 m·kgf, 90 ft·lbf)
Locknut
21 Nm (2.1 m·kgf, 15 ft·lbf)
2
1
3
a
T R..
T R..
1
2

FRONT BRAKE
5-13
EAS2GB2169
FRONT BRAKE
Removing the front brake caliper
Order Part name Q’ty Remarks
Brake fluidDrain.
Refer to “BLEEDING THE BRAKE SYSTEM”
on page 3-24.
1 Union bolt 1
2 Copper washers 2
3 Front brake hose 1
4 Brake pad pin plug 1
5 Brake pad pin 1
6 Brake pads 2
7 Brake pad spring 2
8 Front brake caliper assembly 1
9 Front brake caliper bracket 1
For installation, reverse the removal proce-
dure.
3
9
1
2
8
4
5 7
6
T.R.30 Nm (3.0 mlbf) kgf, 22 ft
T.R.23 Nm (2.3 mlbf) kgf, 17 ft
T.R.17 Nm (1.7 mlbf) kgf, 12 ft
T.R.2.5 Nm (0.25 mlbf) kgf, 1.8 ft
T.R.6 Nm (0.6 mlbf) kgf, 4.3 ft

FRONT BRAKE
5-14
Disassembling the front brake caliper
Order Part name Q’ty Remarks
1 Brake caliper piston 2
2 Brake caliper piston dust seal 2
3 Brake caliper piston seal 2
4 Bleed screw 1
For assembly, reverse the disassemble pro-
cedure.
12
34
S
S
BF
BFT R..
S
6 Nm (0.6 m
kgf, 4.3 ft Ibf)

FRONT BRAKE
5-15
Removing the front brake master cylinder
Order Part name Q’ty Remarks
Brake fluidDrain.
Refer to “BLEEDING THE BRAKE SYSTEM”
on page 3-24.
1 Brake lever 1
2 Union bolt 1
3 Copper washers 2
4 Front brake hose 1
5 Brake master cylinder reservoir cap 1
6 Brake master cylinder reservoir diaphragm 1
7 Front brake master cylinder float 1
8 Front brake master cylinder holder 1
9 Front brake master cylinder 1
For installation, reverse the removal proce-
dure.
S1
23
4 5
68
9
S
7
T R..
T R..
T R..
T R..

FRONT BRAKE
5-16
Disassembling the front brake master cylinder
Order Part name Q’ty Remarks
1 Dust boot 1
2 Circlip 1
3Washer 1
4 Brake master cylinder kit 1
For assembly, reverse the disassemble pro-
cedure.
4 1
2
3

FRONT BRAKE
5-17
EAS2GB2170INTRODUCTIONEWA
WARNING
If you need to disassemble the disc brake
components, observe the following precau-
tions.
• Never disassemble the brake components
unless absolutely necessary.
• If there is any problem with connections
on the hydraulic brake system, perform
the following jobs.
Disassemble the brake system, drain the
brake fluid, and clean it. After that, add a
suitable amount of brake fluid. Then, bleed
it after reassembly.
• Use only brake fluid for washing brake
components.
• Use new brake fluid for cleaning the brake
components.
• Immediately wipe off the spilled brake fluid
to avoid damage to painted surfaces or
plastic parts.
• Handle brake fluid with special care not to
let it enter your eyes so that you may not
lost your eyesight.
• FIRST AID FOR BRAKE FLUID ENTERING
THE EYES:
• Flush with water for 15 minutes and get
immediate medical attention.
EAS2GB2171CHECKING THE FRONT BRAKE DISC
1. Remove:
• Front wheel
Refer to “FRONT WHEEL” on page 5-4.
2. Check:
• Front brake disc
Damage/galling  Replace.
3. Measure:
• Brake disc thickness
Measure the brake disc thickness at a few
different locations.
Out of specification  Replace.4. Install:
• Front wheel
Refer to “FRONT WHEEL” on page 5-4.
EAS2GB2172REMOVING THE FRONT BRAKE CALIPER
TIP
Before disassembling the brake caliper, drain
the brake fluid from the entire brake system.
1. Remove:
• Union bolt
• Copper washers
• Brake hose
TIP
Put the end of the brake hose into a container
and pump out the brake fluid.
EAS2GB2173DISASSEMBLING THE FRONT BRAKE CAL-
IPER
1. Remove:
• Brake caliper piston “1”
• Brake caliper piston dust seal “2”
• Brake caliper piston seals “3”
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a. Blow compressed air into the brake hose
joint opening to force out the piston from the
brake caliper.
EWA
WARNING
• 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.
Brake disc thickness limit
2.5 mm (0.10 in)
3
2
1

FRONT BRAKE
5-18
b. Remove the brake caliper piston dust seal
and the brake caliper piston seal.
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EAS2GB2174CHECKING THE FRONT BRAKE CALIPER
1. Check:
• Brake caliper piston “1”
Rust/scratches/wear  Replace the brake
caliper piston.
• Brake caliper cylinder “2”
Scratches/wear  Replace the brake cali-
per assembly.
• Brake caliper body “3”
Cracks/damage  Replace the brake cali-
per assembly.
• Brake fluid delivery passages
(brake caliper body)
Obstruction  Blow out with compressed
air.
EWA
WARNING
When the brake caliper is disassembled, re-
place the brake caliper piston seal and the
brake caliper piston dust seal with new
ones.
2. Check:
• Brake caliper bracket
Crack/damage  Replace.
EAS2GB2175
ASSEMBLING THE FRONT BRAKE CALI-
PER
EWA
WARNING
• Before installation, clean and lubricate the
internal parts. Use new brake fluid for
cleaning and lubricating.
• Never use solvents on internal brake com-
ponents as they will cause the piston seals
to swell and distort.
• When the brake caliper is disassembled,
replace the brake caliper piston seal and
the brake caliper piston dust seal with new
ones.
EAS2GB2176INSTALLING THE BRAKE CALIPER PISTON
1. Clean:
• Brake caliper
• Brake caliper piston seal
• Brake caliper piston dust seal
• Brake caliper piston
Use brake fluid for cleaning.
2. Install:
• Brake caliper piston seals “1”
• Brake caliper piston dust seal “2”
EWA
WARNING
Always use new brake caliper piston seal
and brake caliper piston dust seal.
TIP
• Apply the silicone grease on the brake caliper
piston seal and brake caliper piston dust seal.
• Fit the brake caliper piston seal and the brake
caliper piston dust seal into the grooves in the
brake caliper correctly.
2
113
Recommended brake fluid
DOT 4
New
New
1
1
22