Yamaha YZ 2018 Series, Owner'S Service Manual

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CHASSIS
3-28
EWA
WARNING
• Use only the designated brake fluid. Other
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 flu-
ids may result in a harmful chemical reac-
tion, 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.
ECA
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
EASB29B098
ADJUSTING THE DRIVE CHAIN SLACK
ECA
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
swingarm or cause an accident. Therefore,
keep the drive chain slack within the speci-
fied limits.
1. Use a suitable stand to raise the rear wheel
off the ground.
EWA
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.
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.
TIP
• To maintain the proper wheel alignment, ad-
just 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.
e. Tighten the locknut.
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Drive chain slack (Maintenance
stand)
50.0–60.0 mm (1.97–2.36 in)
Direction “a”
The drive chain slack decreases.
Direction “b”
The drive chain slack increases.
Wheel axle nut
125 N·m (12.5 kgf·m, 92 lb·ft)
Locknut
21 N·m (2.1 kgf·m, 15 lb·ft)
a
1
3
2
a
b
T
R
.
.
T
R
.
.