Yamaha YZ250 2021, Owner'S Manual

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CHAIN DRIVE
4-30
c. Remove the drive chain from the kerosene
and completely dry it.
4. Check:
•
Drive chain roller “1”
Damage/wear

Replace the drive chain.
•
Drive chain side plate “2”
Damage/wear

Replace the drive chain.
5. Lubricate:
•
Drive chain
EAM30560
CHECKING THE DRIVE CHAIN (for YZ250X)
1. Measure:
• 15-link section of the drive chain
Out of specification

Replace the drive
chain.
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.
15-link length limit
239.3 mm (9.42 in) (YZ250X)
G088940
2
1
G088942
G088937
G088938
G088939