has it got a bigger carb on it or has it got the standerd carb wich called something like gurtler or sumin if its gt the standerd 1 it cd be tht ur speedfight is running weak and needs a bigger carb on it normaly when a big bore kit is fitted its normaly needs a bigger carb or a massive rejet but yes like u sed it cd need lighter rollers in there but sounds to me as if its the carb
nick muller
March 2008