The new belt on my 90 RS is turning into rubber powder thats gettin everywhere on the front of the engine. The belt is clear of everything
and belt is the right one and a quality belt. Fraying is mostly on the outside of the belt. The last belt I had did the same thing I figured it was the belt. Help me out.

 

Only time I encountered that it was on the INSIDE (ribbed side) of the belt. The distance between the tensioner pulley and the water pump pulley was very close and it would make very slight contact sometimes at high RPMs, covering the intake and front of the motor with little rubber pieces.

Having the outside (flat side) the belt coming apart sounds different. The only 2 pulleys that contact the outside of the belt are the tensioner pulley and the water pump pulley.

 

Make sure all of your pulleys are lined up correctly.