I have a 1989 750 with a problem. It will start and run for 5 minutes or so and then die, let it sit for a few minutes and it will start and run a few minutes and then die again. I have pulled the plugs out of the bowls on the carbs and gas will run out so it´s not that. Could the coils or magnito be bad or is there something else I can check. Help!!!! Thanks.