Yamaha YZ450FP 2023, Owner'S Service Manual

Page: 136 / 388

FRONT BRAKE
4-20
EAM30028
INTRODUCTION
WARNING
EWA19210
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 sys-
tem, 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 im-
mediate medical attention.
EAM30029
CHECKING THE FRONT BRAKE DISC
1. Check:
• Front brake disc
Damage/galling

Replace.
2. Measure:
•
Brake disc thickness
Measure the brake disc thickness at a few dif-
ferent locations.
Out of specification

Replace.
3. Measure:
• Brake disc runout
Out of specification

Replace the brake
disc.
a. Place the vehicle on a maintenance stand
so that the front wheel is elevated.
b. Remove the brake caliper.
c. Hold the dial gauge at a right angle against
the brake disc surface.
d. Measure the runout 1.5 mm (0.06 in)
above the brake disc edge.
4. Replace:
• Brake disc
Refer to “ASSEMBLING THE FRONT
WHEEL” on page 4-8.
EAM30519
REPLACING THE FRONT BRAKE PADS
TIP
When replacing the brake pads, it is not neces-
sary to disconnect the brake hose or disassem-
ble the brake caliper.
1. Remove:
•
Brake pad
a. Remove the pad pin plug “1”.
b. Loosen the pad pin “2”.
c. Remove the brake caliper “3” from the
front fork.
d. Remove the pad pin and brake pads “4”.
Brake disc thickness limit
2.5 mm (0.10 in)
Brake disc runout limit (as mea-
sured on wheel)
0.15 mm (0.0059 in)
G098641
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3
2