I acquired a 2008 crf250r that supposedly had been rebuilt, but didn't have spark. Well I replaced Cdi box and got fire. Could not kick bike for nothing. Bump started on second try and ran like crap, popping and sputtering. The head pipe was also glowing red after 30 seconds of run time. Could it be valve adjustment or maybe a tooth off? Gonna take it apart Monday. Anyone have this problem before?