Doing a similar conversion on my 750 ES. I found a GS500 sprocket carrier is much narrower and puts the chain about 5mm too close to the centre, or a Bandit / Teapot carrier puts the chain about 13mm too far over.
So either have the bandit one machined down, or use the GS500 one with a spacer (a standard GS500 rear sprocket is 520 and is about 5mm thick where it bolts onto the hub. Could use and old sprocket as a spacer.
have you drilled the frame pivot out to 20mm or are you using new tophats for the arm?
