Hello all, My friend just bought a wrecked 98' fzr600. he plans on fixing it up and turning it into his track day beater. well, the stock exhaust was destroyed so he yanked it. I looked inth eexhaust ports and saw a lot of carbon build up. all over the walls of the ports and the valve stem. I was wondering if there was any good way to clean them up with out taking the engine apart. they don't need to be perfect, we just don't want to cause any more damage then good. This bike isn't going to be hopped up at all. most parts will be replaced with stock equipment. he just wants a beater that works, so he can become a better rider.