I think the previous owner of my Bullet has over-tightened the primary chain. When I poke a small screwdriver through the inspection hole I can't detect any slack in the chain whatsoever, even after rotating it around and checking different spots. It's probably run a thousand miles like this and I'm now worried that it may have damaged the gearbox bearings, perhaps. Should I continue to run it like this and just let it get slack from wear or should I take off the casing and check it out?