I have '88 Exciter 570. It broke a fairly new drive belt recently, but seemed ok with a new belt put on. Last I was riding and it made a squeeling noise, then the engine died (I was going about 30 MPH). It restarted but quickly died, like it was bound up. It was locked up, but I was able to move the belt and sheaves a little, and it restarted, and died quickly again. I took the belt off, engine starts and runs great. Do I have a sheave alignment issue, or adjustment issue? Can I tell from looking at it what might be wrong? Movebale sheave locked up or something? Need help/advice on what to check.