I recently wrecked my brand new to me 05 bayou. The PO had never run a battery in it, and I hadn't bought one for it. After the accident, it only runs with a battery attached to it and dies when you take the battery off. I read somewhere that a battery is necessary to regulate voltage to the coils (Or something along those lines) but it ran beautifully before the accident so I'm confused. My working theory is that being ran without the battery weakened the coils and the impact (Stationary object at 40 mph, Most of the concussion is gone ) caused them to disintegrate, but I have a basic at best knowledge of ICE ignition knowledge and what someone to either confirm or deny before i go tearing into things.