Loosen the carrier bolts. The two long ones parallel to the axle. Then using a 12mm wrench loosen the nuts that are on the bolts sticking out behind the axle. You then use a 10mm to start tighning the bolts untill the chain has about 1inch of up and down play. You may need to thread the 12mm nuts out as you tighten the bolts. Then once its adjusted you will tighten the 12mm back and the carrier bolts and good to go. If your bolts are all the way in it may be time to take a link out of the chain or possibly get a new chain. Hope this helps!