Re: Is it possible?
If the issue is only 1/8" I'd offset the rear sprocket outboard. 1/8" shouldn't be enough to derail the chain unless your tensioner is not aligned and it's pulling the chain off to one side. Are you certain the engine is centered in the frame and not cocked off center?
Take a good look from the rear of the bike forward and check to see you have a straight line between the sprockets and the tensioner. Better yet, lay a straight edge along the sprockets. I like to use a length of 1/4" aluminum channel. I clamp it to the rear sprocket next to the teeth then check to see where/how it lays at the engine drive sprocket.
Ideally it should touch at exactly the same place on both sprockets. Your straight edge must be flat against one or the other sprocket, touching it on both sides and it should mate exactly with the other sprocket.
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