I'm not sure what year you are talking about, but if it's an old one, yank the whole carb and clean all the jets and idle air and pilot air. Just boil the whole carb after you remove the needle's and jets and such. Remove every moving part and strip it down. Then boil it. If you're still having problems, and the carb isn't the one that originally came with the bike ( Replacement) then check all the needles to make sure they are the correct ones. you can find most guides for bikes online. or just buy one.
