Original owner of a 1999 WR125. It has not been raced but has not been babied. It was used for several years, sat for 8 years, and I started back up again last year. The bike has had almost no work performed on it and I actually replaced the original tire last week. There has never been a problem with fouling, but the past few times out, I have been fouling plugs. The plug is black and wet. I am using the prescribed plug, have not messed with the carb, 92 octane, 42-1 with Spectra. Just wondering if the piston/ring should be replaced after all of these years? I have no idea how many hours I have on it, probably 15 this year, and the same last year. Hmmm, at least 100 hours over its life, but that is just a guess. Would it be a good idea just to go ahead and redo the top end? Or mess with the carb?