This has been giving problems for days now. The bike will run great at 1/2-WOT throttle but under half throttle it studders. Then if i run it open to long it will studder more. Ive noticed that my fuel filter is filling up and not running down under load. I dont know I need help....new carb, or something. I feel like I work on this thing more than I ride it. Ive replaced everything from the jet in the carb to the whole engine assembly. im on my third tank of fuel and running the bike at 4oz/gallon 32:1 of 87 unleaded. The carb has Delortto #68 main jet in it and the needle clip is on the 3rd slot from the top. On the first and second slot the engine bogged off idle. On the third slot, no bogging. my plugged is gapped at .022 and im using the stock airbox. Can anyone tell me why the carb would spit fuel back outta the carb inlet? I had the filter off the other day and if givin constant throttle the carb would begin to spit fuel back out. This is fouling up the filter, and making a mess. I dont have a air leak and all my gaskets are good. Any help would be great. Thanx Billy.