2002 YAMAHA WR 250F warning

5 - 16
CHASFRONT BRAKE AND REAR BRAKE
Brake caliper piston seal kit
1. Remove:
Dust seal 1
Piston seal 2
NOTE:
Remove the piston seals and dust seals by
pushing them with a finger.
CAUTION:
Never attempt to pry out piston seals and
dust seals.
WARNING
Replace the piston seals and dust seals
whenever a caliper is disassembled.
ÅFront
ıRear
Å
ı
EC5A4000
INSPECTION
Brake master cylinder
1. Inspect:
Brake master cylinder inner surface a
Wear/scratches → Replace master cyl-
inder assembly.
Stains → Clean.
WARNING
Use only new brake fluid.
ÅFront
ıRear
2. Inspect:
Diaphragm 1
Crack/damage → Replace.
ÅFront
ıRear
ı Å
ı
Å
3. Inspect:
Brake master cylinder piston 1
Brake master cylinder cup 2
Wear/damage/score marks → Replace
brake master cylinder kit.
ÅFront
ıRear
Åı

5 - 17
CHAS
Brake caliper
1. Inspect:
Brake caliper cylinder inner surface a
Wear/score marks → Replace brake
caliper assembly.
ÅFront
ıRear
ı Å
2. Inspect:
Brake caliper piston 1
Wear/score marks → Replace brake
caliper piston assembly.
WARNING
Replace the piston seals and dust seals 2
whenever a caliper is disassembled.
EC534301
Brake hose
1. Inspect:
Brake hose 1
Crack/damage → Replace.
EC5A5000
ASSEMBLY AND INSTALLATION
WARNING
All internal parts should be cleaned in
new brake fluid only.
Internal parts should be lubricated with
brake fluid when installed.
Replace the piston seals and dust seals
whenever a caliper is disassembled.
Brake caliper piston
1. Clean:
Brake caliper
Piston seal
Dust seal
Brake caliper piston
Clean them with brake fluid.
FRONT BRAKE AND REAR BRAKE

5 - 18
CHAS
2. Install:
Piston seal 1
Dust seal 2
WARNING
Always use new piston seals and dust
seals.
NOTE:
Fit the piston seals and dust seals onto the slot
on brake caliper correctly.
ÅFront
ıRear
Å
ı
3. Install:
Brake caliper piston 1
NOTE:
Apply the brake fluid on the piston wall.
CAUTION:
For the front brake caliper, install the pis-
ton with its depressed side a facing the
brake caliper. For the rear brake caliper,
install the piston with its shallow
depressed side b facing the caliper.
Never force to insert.
ÅFront
ıRear
Front brake caliper
1. Install:
Pad support 1
Brake pad 2
Pad pin 3
NOTE:
Install the brake pads with their projections
a into the brake caliper recesses b.
Temporarily tighten the pad pin at this point.
Å
ı
FRONT BRAKE AND REAR BRAKE

5 - 19
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Copper washer 1
Union bolt 2
WARNING
Always use new copper washers.
CAUTION:
Install the brake hose so that its pipe por-
tion a directs as show and lightly touches
the projection b on the brake caliper.
T R..30 Nm (3.0 m · kg, 22 ft · lb)
3. Install:
Brake hose holder 1
Brake caliper 2
Bolt (brake caliper) 3
NOTE:
Fit the brake hose holder cut a over the pro-
jection b on the front fork and clamp the brake
hose.
4. Tighten:
Pad pin 4
5. Install:
Pad pin plug 5
Rear brake caliper
1. Install:
Pad support 1
Brake pad 2
Pad pin 3
NOTE:
Install the brake pads with their projections
a into the brake caliper recesses b.
Temporarily tighten the pad pin at this point.
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)

5 - 20
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Brake disc cover 1
Bolt (brake disc cover) 2
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
3. Install:
Copper washer 1
Brake hose 2
Union bolt 3
WARNING
Always use new copper washers.
CAUTION:
Install the brake hose to the brake caliper
with the paint a on the pipe facing the
brake caliper and with the pipe contacting
the brake caliper projection b.
T R..30 Nm (3.0 m · kg, 22 ft · lb)
4. Install:
Brake caliper 1
Rear wheel 2
Refer to “FRONT WHEEL AND REAR
WHEEL” section.
5. Tighten:
Pad pin 3
6. Install:
Pad pin plug 4
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)

5 - 21
CHASFRONT BRAKE AND REAR BRAKE
Brake master cylinder kit
1. Clean:
Brake master cylinder
Brake master cylinder kit
Clean them with brake fluid.
2. Install:
Brake master cylinder cup (primary) 1
Brake master cylinder cup (secondary)
2
To brake master cylinder piston 3.
NOTE:
Apply the brake fluid on the brake master cyl-
inder cup.
WARNING
After installing, cylinder cup should be
installed as shown direction. Wrong instal-
lation cause improper brake performance.
ÅFront
ıRear
Åı
Åı
3. Install:
Spring 1
To brake master cylinder piston 2.
NOTE:
Install the spring at the smaller dia. side.
ÅFront
ıRear
Åı

5 - 25
CHASFRONT BRAKE AND REAR BRAKE
4. Install:
Copper washer 1
Brake hose 2
Union bolt 3
WARNING
Always use new copper washers.
CAUTION:
Install the brake hose so that it contacts
the master cylinder projection a and that
its bent portion b faces downward.
T R..30 Nm (3.0 m · kg, 22 ft · lb)
Rear brake hose
1. Install:
Copper washer 1
Brake hose 2
Copper washer 3
Union bolt 4
WARNING
Always use new copper washers.
CAUTION:
When installing the brake hose, first align
the tooth a on the copper washer 1 with
the projection b on the brake master cylin-
der. Then, align the pipe portion c on the
end of the brake hose with the tooth d on
the copper washer 1 and tighten the union
bolt.
T R..30 Nm (3.0 m · kg, 22 ft · lb)

5 - 26
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Brake hose holder 1
Screw (brake hose holder) 2
CAUTION:
After installing the brake hose holders,
make sure the brake hose does not contact
the spring (rear shock absorber). If it does,
correct its twist.
Brake fluid
1. Fill:
Brake fluid
Until the fluid level reaches “LOWER”
level line a.
WARNING
Use only the designated quality brake
fluid:
otherwise, the rubber seals may deterio-
rate, causing leakage and poor brake per-
formance.
Refill with the same type of brake fluid;
mixing fluids may result in a harmful chem-
ical reaction and lead to poor performance.
Be careful that water does not enter the
master cylinder when refilling. Water will
significantly lower the boiling point of the
fluid and may result in vapor lock.
CAUTION:
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
ÅFront
ıRear
Recommended brake fluid:
DOT #4
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)
Å
ı