Pulled tire to have it replaced and I noticed that the belt had what looked like scuffing on one side and the pully had what looks like a mettalic substance on the same side of the pully down in the grooves. The Harley shop was the last to adjust it and it is soon to be going back in. What do you think.

 

May be as simple as the wheel slightly out of alignment, pulling the belt over to that side of the pulley. If the bike is going in for a service get them to check vehicle and wheel alignment, but tell them why and talk it through with them.

 

check and clean belt and spocket,