Remove the front seat.
Locate the large hex nut that holds the rear axle bolt in place.
Loosen the hex nut enough so that the axle bolt can be turned.
Remove the cotter pin from the axle bolt.
Turn the axle bolt counterclockwise to loosen it.
Slide the rear wheel forward until the chain is tight.
Tighten the axle bolt to 19–22 ft-lb.
Replace the cotter pin.
Tighten the hex nut.
Replace the front seat.
Test the chain tension by pushing up and down on it with your hand. The chain should have about 1/2 inch of play. If it has more or less play, repeat steps 3-11 until the chain tension is correct.
