Yamaha YZ450FP 2023, Owner'S Service Manual

Page: 105 / 388

CHASSIS
3-27
to fully extend.
g. Tighten the bleed screw and then release
the brake lever or brake pedal.
h. Repeat steps (d) to (g) until all of the air
bubbles have disappeared from the brake
fluid in the plastic hose.
TIP
During the procedure, keep adding brake fluid to
the reservoir.
NOTICE
ECA24320
• Wipe off any brake fluid on the brake discs,
tires, wheels, etc.
• Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
i. Tighten the bleed screw.
j. Pour brake fluid to the reservoir up to the
specified level.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-24.
WARNING
EWA13110
After bleeding the hydraulic brake system,
check the brake operation.
EAM30481
DRIVE CHAIN SLACK
NOTICE
ECA13550
A drive chain that is too tight will overload
the engine and other vital parts, and one that
is too loose can skip and damage the swing-
arm or cause an accident. Therefore, keep
the drive chain slack within the specified lim-
its.
Checking the drive chain slack
1. Use a maintenance stand to raise the rear
wheel off the ground.
WARNING
EWA13120
Securely support the vehicle so that there is
no danger of it falling over.
2. Shift the transmission into the neutral posi-
tion.
3. Pull the drive chain up above the drive chain
guide installation bolt with a force of about 50
N (5.0 kgf, 37 lbf).
4. Check:
• Drive chain slack “a”
Out of specification

Regulate.
TIP
Measure drive chain slack between the drive
chain guide and the bottom of the chain as
shown.
Adjusting the drive chain slack
WARNING
EWA13120
Securely support the vehicle so that there is
no danger of it falling over.
1. Adjust:
•
Drive chain slack
a. Loosen the wheel axle nut “1”.
b. Loosen both locknuts “2”.
c. Turn the adjusting bolt “3” until the speci-
fied drive chain slack is obtained.
TIP
• To maintain the proper wheel alignment, adjust
both sides evenly.
•
Push the rear wheel forward to make sure that
there is no clearance between the swingarm
end plates and the ends of the swingarm.
d. Tighten the wheel axle nut.
Bleed screw
5 N·m (0.5 kgf·m, 3.7 lb·ft)
T
R
.
.
Drive chain slack (Maintenance
Stand)
50.0–60.0 mm (1.97–2.36 in)
a a
1
3 3 3 2 2 2