there is a round black piece of plastic in the center if the driven. in the center is a pipe plug. use the tool that fits it from your tool kit and loosen it 4 turns (counterclockwise) then use the fork tool to turn the plastic adjuster clockwise to open the shives. remove and install the belt. then turn the adjusted counterclockwise and adjust the deflection. You will have to work the belt out of the shives until you have the proper deflection (about 1.5 inches) make shure the adjuster nut is touching the shive and tighen the set plug in the center. If you have not cut the slits through on the adjuster you should tak the time to it will help the adjuster stay tight.
