Mike,
You can buy a rare earth magnet at Radio Shack and they work great. Just hook up your ignition and pass the magnet under the pick-up, it will only fire with one side of the magnet. Make sure your ignition is hooked to the plug and just ground the plug to the head. i have a few that you can actually hear firing with the plug installed. Most ignitions have a warning telling you to "NOT" fire the ignition without a plug attached. Hope that helps