Yamaha YZF-R125 Service Manual: Adjusting the drive chain slack

NOTE:

The drive chain slack must be checked at the tightest point on the chain.

CAUTION:

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 specified limits.

1. Stand the vehicle on a level surface.

WARNING

Securely support the vehicle so that there is no danger of it falling over.

NOTE:

Both wheels should be on the ground without a rider on the vehicle.

2. Turn the rear wheel several times and find the tightest position on the drive chain.

3. Check:

  • Drive chain slack "a" Out of specification Adjust.

Adjusting the drive chain slack


NOTE:

Measure the drive chain slack halfway between the drive axle and the rear wheel axle.

4. Adjust:

  • Drive chain slack

a. Loosen the wheel axle nut "1".

b. Loosen both locknuts "2".

c. Turn both adjusting bolts "3" in direction "a" or "b" until the specified drive chain slack is obtained.


Adjusting the drive chain slack


NOTE:

  • To maintain the proper wheel alignment, adjust both sides evenly
  • Push the rear wheel forward to make sure there is no clearance between the drive chain pullers and the ends of the adjusting bolts.

d. Tighten the wheel axle nut to specification.


e. Tighten the locknuts to specification.


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