Removing The Drive Chain; Checking The Drive Chain - Yamaha WR250R Service Manual

EAS23420

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.
NOTE:
Place the vehicle on a suitable stand so that the
rear wheel is elevated.
2. Remove:
Drive sprocket nut "1"
G
NOTE:
Return the bent tab of the locknut.
G
Operate the rear brake, and loosen the drive
G
sprocket.
After loosening the drive sprocket, remove the
G
rear wheel and swingarm.
3. Remove:
Rear wheel
G
Refer to "REAR WHEEL" on page 4-7.
Rear shock absorber
G
Refer to "REAR SHOCK ABSORBER AS-
SEMBLY" on page 4-53.
Swingarm
G
Refer to "SWINGARM" on page 4-56.
4. Remove:
Drive chain
G
EAS23441

CHECKING THE DRIVE CHAIN

1. Measure:
15-link section "a" of the drive chain
G
Out of specification → Replace the drive
chain.
15-link length limit
239.3 mm (9.42 in)
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a. Measure the length "a" between the inner
sides of the pins and the length "b" between
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 section
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
1
NOTE:
When measuring a 15-link section of the drive
G
chain, make sure that the drive chain is taut.
Perform this procedure 2–3 times, at a different
G
location each time.
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2. Check:
Drive chain
G
Stiffness → Clean, lubricate, or replace.
3. Clean:
Drive chain
G
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a. Wipe the drive chain with a clean cloth.
b. Put the drive chain in kerosene and remove
any remaining dirt.
4-60
CHAIN DRIVE