Kehein are onli good if you realy need the power i rode the all the Youth B natioanls with out one but put one on for the last year cus i really needed it. i hav jus put one on my sherco an its runs perfect but they take alot on time to jet them up right and they take alot of maintainig. also u need a stedy hand becus if i bend the floats by even a miilimeter the carb runs ****