06 510smr. i am borrowing it from a friend and am tuning a bit for him while he is out of town. it is ruunin rich. how do you lean it out. i know it's a keihin fcr41. i was backfiring kinda bad on decel if you were getting on it. which leads me to believe it's rich. i checked the main and it was a 185. little big i think. i pulled it and put in a 182. took her for a spin and it runs great. little pop here and there but damm close. i am concered about sitting at idel if you try to wack the throttle it chokes out. ideas. other than that this thing is a monster.