I recently changed from the stock pipe to a FMF Fatty pipe. Upon removing the stock pipe I noticed about a quarter of an inch of solid carbon inside of the pipe, at least where it meets up with the engine. I bought the 1994 KDX 200 with 500 miles on the odometer last year. It was about a half year before I changed the jetting and plug (to br8eg) to get it from running so rich. I also switched to Mobile 1 Sythnetic 2 cycle oil 40:1. What causes the carbon and what can I do to help eliminate carbon deposits in my new FMF pipe? Thanks!!!