Yamaha YZ250 2021 Owner's Manual

CHAIN DRIVE4-30c. Remove the drive chain from the keroseneand 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 chainEAM30560CHECKING THE DRIVE CHAIN (for YZ250X)1. Measure:• 15-link section of the drive chainOut of specification  Replace the drivechain.a. Measure the length “a” between the innersides 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 inthe illustration.b. Calculate the length “c” of the 15-link sec-tion of the drive chain using the followingformula.Drive chain 15-link section length “c” =(length “a” between pin inner sides +length “b” between pin outer sides)/2TIP• When measuring a 15-link section of the drivechain, make sure that the drive chain is taut.• Perform this procedure 2–3 times, at a differentlocation each time.2. Check:• Drive chainStiffness  Clean, lubricate, or replace.3. Clean:• Drive chaina. 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 keroseneand completely dry it.15-link length limit239.3 mm (9.42 in) (YZ250X)G08894021G088942G088937G088938G088939