i would go to like a 42 pilot, that is what i have in mine and i still don't have to choke it.... and as for main i think i have a 180 in mine and i fould my plugs last time i was trail riding,,,,, at the dunes it did good, needed to get it hot. i think i will be dropping a clip position and another size or 2 on the main, like a 175 or 170...
good luck and if you get it perfect before i do,,,, hook a brother up