i have cut the airbox open,uncorked the exhaust,welded a downward s.s. tip on the end cap,,(almost sounds as good as the 250f!! ) i have 117.5 main in until my 115 gets here, it runs great, very good response, but on top end i get this "sputter" almost like my rev limiter on my 250f but these bikes dont have one do they??? what is it , how to get rid of it,and is it harming anything??? also what rear sprocket is everyone running???? stock on the short version is 49,,,im thinking of a 52,,,any thoughts or where to get one??? these free mods make it rip for what it is....thanks cw :confused: