Adjusting The Drive Chain Slack - Yamaha YZ450FX 2019 Owner's Service Manual

brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
brake performance.
• Refill with the same type of brake fluid that
is already in the system. Mixing brake fluids
may result in a harmful chemical reaction,
leading to poor brake performance.
• When refilling, be careful that water does
not enter the brake fluid reservoir. Water
will significantly lower the boiling point of
the brake fluid and could cause vapor lock.
ECA13540
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean up
any spilt brake fluid immediately.
EAM30235

ADJUSTING THE DRIVE CHAIN SLACK

ECA13550
NOTICE
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.
1. Use a maintenance stand to raise the rear
wheel off the ground.
EWA13120
WARNING
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, 36 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.
Drive chain slack (Maintenance
stand)
50.0–60.0 mm (1.97–2.36 in)
5. Adjust:
• Drive chain slack
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Loosen the wheel axle nut "1".
b. Loosen both locknuts "2".
c. Turn the adjusting bolt "3" in direction "a" or
"b" until the specified drive chain slack is ob-
tained.
Direction "a"
The drive chain slack decreases.
Direction "b"
The drive chain slack increases.
1
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.
Wheel axle nut
125 N·m (12.5 kgf·m, 92 lb·ft)
e. Tighten the drive chain puller locknut.
3-27
CHASSIS
a a
a
b
2
3