Is there any way to tell if I still have the stock pistion in my '98 KDX220 by looking in the exhaust port? I just got this bike and I have no idea what has been done to it. I would think that after 13 years it has probably had the piston changed, but is there any way to tell without removing the cylinder? If I remove the cylinder and check, should I just replace the rings or should I replace the piston too, even if it has an aftermarket pistion? Everything looks clean and I can't see any scars in the piston or cylinder. The head doesn't have any carbon build up on it as far as I can see. When I drained the oil out of the transmission it was gray and kind of metalic looking. Is this normal (maybe from the clutches) or do I need to look for something going bad?