I to had one pop before I figured out how to start it. Cold, pump 3 times then let it sit 30-45 seconds. One more pump, throttle partially open and crank with ignition on. It'll start in less than 2 revolutions. Warm needs only 1 pump and sit 15-20 seconds, no 2nd pump before the same crank procedure. Real cold needs a fender cover thrown over the carbs along with the cold procedure.
Doug