I have a 2006 Ness Jackpot and tried to start the bike today after riding last weekend and it will barely idle and will not take any acceleration. It pops and backfires and then stalls. I checked the plugs and they are dry black carbon covered. Replaced plugs with no improvement. I filled the tank during my ride and then rode 70 miles with no problems. Could I have gotten bad gas or something else? There has not been any problems with the bike before this.