Removing The Drive Chain; Checking The Drive Chain - Yamaha YZ 2020 Series Owner's Service Manual

EAM30075

REMOVING THE DRIVE CHAIN

1. Stand the vehicle on a level surface.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
TIP
Place the vehicle on a maintenance stand so
that the rear wheel is elevated.
2. Remove:
• Drive chain
TIP
Cut the drive chain with the drive chain cut & riv-
et tool. (Use goods on the market.)
EAM30076

CHECKING THE DRIVE CHAIN

1. Measure:
• 15-link section of the drive chain
Out of specification  Replace the drive
chain.
15-link length limit
239.3 mm (9.42 in)
a. Measure the length "a" between the inner
sides of the pins and the length "b" be-
tween the outer sides of the pins on a 15-
link section of the drive chain as shown in
the illustration.
b. Calculate the length "c" of the 15-link sec-
tion of the drive chain using the following
formula.
Drive chain 15-link section length "c" =
(length "a" between pin inner sides +
length "b" between pin outer sides)/2
TIP
• When measuring a 15-link section of the drive
chain, make sure that the drive chain is taut.
• Perform this procedure 2–3 times, at a different
location each time.
2. Check:
• Drive chain
Stiffness  Clean, lubricate, or replace.
3. Clean:
• Drive chain
a. Wipe the drive chain with a clean cloth.
b. Put the drive chain in kerosene and re-
move any remaining dirt.
c. Remove the drive chain from the kerosene
and completely dry it.
ECA19090
NOTICE
• This vehicle has a drive chain with small
rubber O-rings "1" between the drive chain
side plates. Never use high-pressure water
or air, steam, gasoline, certain solvents
(e.g., benzine), or a coarse brush to clean
the drive chain. High-pressure methods
could force dirt or water into the drive
chain's internals, and solvents will deterio-
rate the O-rings. A coarse brush can also
damage the O-rings. Therefore, use only
kerosene to clean the drive chain.
• Do not soak the drive chain in kerosene for
more than ten minutes, otherwise the O-
rings can be damaged.
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CHAIN DRIVE