If the engine is shifted too far left, then it seems there is a good chance the engine sprocket is not aligned properly with the clutch basket sprocket. If they are both shifted over, then it seems a good chance the gearbox drive sprocket is misaligned with the final sprocket at the rear wheel. I wonder, really not sure, if adding spacer thickness between crankcase and inner primary won't cause inner primary to interfere with the clutch basket (the inner primary may already be unusually close to the clutch basket). I guess I'm saying that a dose of diagnostics would inform the decision on the cure.
Richard L.