Morning.., I purchased a 03 EG when I changed out my rear rim from stock to 18...., I could hear the belt rubbing the tire, when pushing it backwards/forward.... just recently when I had the bags off, cleaning and inspecting I can see where the belt has been rubbing the tire..I may have ran it 500 miles. the tire is a 150/70/18. Would a smaller tire correct this..., if so what size. Or do I have another issue. The rim is straight.

 

There are a couple of possibilities to check. Running a wider than stock tyre can cause problems, as I myself have found! Double-check your wheel alignment, which is easiest.

My next suggestion involves removing the wheel, which is to look down the side of the tyre, so the top and bottom edges are in line with each other. The photo shows my current 160/70 tyre and you can see that only the inner rim of the drive pulley is visible. However that is almost 3/16" thick, so you can see that the belt should miss the tyre by that amount, if correctly aligned.

If you cannot see any of that inner rim, or only very little of it, you need a spacer behind the pulley. They are widely available on Ebay etc. I suggest you need a minimum of 3/16" tyre/belt clearance. The front pulley is much wider than the rear and will adjust belt alignment, if you do use a spacer. There is a limit to the width of spacer you can use before the pulley hits the swingarm!