Hi there. So It took my bike in for a valve adjustment. Generally do everything myself but havent adjusted the valves and figured I would have it done professionally. The bike was at the shop for 4 weeks as I had springs ordered for the front end and also sent my seat out to be redone. I figured the gas may have gone bad but I did have the Marine Stabilizer in it. I sprayed seafoam in the carbs and also ran some through the gas and then rode it about 500 miles. My conclusion because, it idles fine and performs well is that there is an airleak. It backfiring and spitting when the throttle is chopped. I remember putting the carbs in myself once and thought they seated but then took the tanks off and could see through the access panels that they weren't quite right. So, before I pull the tanks, any ideas of how I might tell where the airleak is coming from (with suspect that it may have to do with the dis/reassembly from the valve job). your thoughts would be appreciated.