2007 model. When the bike is not running there is fuel dripping out the overflow hole at the bottom of the carb. Petcock only has on and res and prime, so no off position. It keeps on dripping (every few seconds) until tank empty. Would the problem be the petcock or is it the vacuum. I would think that if the vacuum was the problem that the fuel would simply not run. Bike runs fine. Any advice would be appreciated. I do not know the workings of the vacuum system of the carb.