by bogging down do you mean it wants to stall when you hit the gas or when it is running and tryingt o go into second it falls on its face? its either A) a tuning issue or B) the tranny needs to be adjusted. But from what you have said it sounds more like a tuning issue. 9 tims out of 10 if it aint shifting into second its tuned to rich. my suggestion is lean it out about an 1/8 of a turn and see if that gets you anyweres.