We just got a 98 rmx 250. It has a fmf burly on it and has been recently rebuilt.It has the keihin. It starts easy enough but bogs at high rpm. WHen its shifted into second the mid range hits good but when it hits high rpm it bogs and runs bad again. It sounds to me like it needs a smaller main. I just need some jetting specs that are close ,I dont know what jetting is stock but i do know the former owner was playing around with the main.Thanx