My carbureted 2002 Sportster runs and sounds great only problem is when I ride it a good 30 minutes to an hour, It will shut off when I throttle up. Does not shut off if I leave it idling in my garage. It will only happen when I ride it. I carry a spark plug wire checking tool with a light on it so it tells me if there is a spark and when it shuts off, there is no spark at all, it won't turn on. The weird part is that if I leave it alone for 20 to 30 minutes, it will fire back up. Full spark. I've replaced the vacuum petcock with a straight petcock with no vacuum. And I've vacuum checked the VOES switch. The VOES switch works. I don't know what else to check. PLEASE HELP before I take it to the dealer to have them turn me upside down for loose change.