My banshee runs good at an idle and revs up fine. When I put it in gear it bogs alot and eventually stalls out. I can get it out of first for only a short time before it bogs down. While in gear I hold the throttle in one spot and it revs up and down until it dies. I recently replaced all the gaskets, cleaned out the carbs, the bike is leak free and super clean. I haven't messed with my timing at all. Carbs are synched. What the hell could it be?