just going to throw this out there then leave it there. Shortly after buying my 99, we were almost out of gas and shifted to reserve just to have it quit running. long story short, the bike had set for a long time prior to me buying it and i didnt dump and clean the tank because it was running when i got it. So just maybe your problem is crap int the tank. If the bike runs ok for short runs then maybe its comming from somewhere other then the carbs. Always check every possibility.