1.Check your alignment and center to center distance with the proper tools.
If you dont have the c to c tool its right about 10.5" with a quick check on the tape measure.
2. Check your secondary and see if your belt is riding high. If so then you need to remove the washers from the three sheave spacing bolts located on the backside over your secondary. They come from the factory with two washers on each. If the washers have already been removed then you need to replace the bolts. They get the ends worn off over time and change the sheave spacing causing tight belt deflection and the dreaded Yami-creep.