Introduction; Checking The Front Brake Disc - Yamaha WR250R Service Manual

EAS22220

INTRODUCTION

EWA14100
WARNING
Disc brake components rarely require disas-
sembly. Therefore, always follow these pre-
ventive measures:
Never disassemble brake components un-
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less absolutely necessary.
If any connection on the hydraulic brake
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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-
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ponents.
Use only clean or new brake fluid for clean-
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ing brake components.
Brake fluid may damage painted surfaces
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and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
Avoid brake fluid coming into contact with
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the eyes as it can cause serious injury.
FIRST AID FOR BRAKE FLUID ENTERING
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THE EYES:
Flush with water for 15 minutes and get im-
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mediate medical attention.
EAS22230

CHECKING THE FRONT BRAKE DISC

1. Remove:
Front wheel
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Refer to "FRONT WHEEL" on page 4-2.
2. Check:
Front brake disc
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Damage/galling → Replace.
3. Measure:
Brake disc deflection
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Out of specification → Correct the brake disc
deflection or replace the brake disc.
Brake disc deflection limit
0.15 mm (0.0059 in)
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a. Place the vehicle on a suitable stand so that
the front wheel is elevated.
b. Before measuring the front brake disc deflec-
tion, turn the handlebar to the left or right to
ensure that the front wheel is stationary.
c. Remove the brake caliper.
d. Hold the dial gauge at a right angle against
the brake disc surface.
e. Measure the deflection front 10 mm (0.39 in),
rear 7 mm (0.28 in) below the edge of the
brake disc.
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4. Measure:
Brake disc thickness
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Measure the brake disc thickness at a few dif-
ferent locations.
Out of specification → Replace.
Brake disc thickness limit
WR250R 3.0 mm (0.12 in)
WR250X 3.5 mm (0.14 in)
5. Adjust:
Brake disc deflection
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MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
a. Remove the brake disc.
b. Turn the brake disc by one bolt hole.
c. Install the brake disc.
NOTE:
Tighten the brake disc bolts in stages and in a
crisscross pattern.
4-16
FRONT BRAKE