Chain slack

The correct slack is given in the owner's manual and, on most models, on a label on the swingarm; on most road motorcycles it is 20–35 mm. The manual also says whether to measure on the side stand or the centre stand.

• Too tight: loads the output shaft and wheel bearings and stretches the chain quickly.
• Too loose: the chain can jump the sprocket and slap the guides.
• To adjust, loosen the rear axle nut, turn both adjusters equally and check the alignment marks.

If the adjusters have run out, the chain and sprockets are due for replacement.