I have been working on this problem all summer. My daughter has a sportsman 90 that runs fine, until the battery runs down. Then if I charge the battery overnight, it runs great again, until the battery dies again. I pulled the stator and had the shop test it. It was bad, so I replaced it. I charged the battery, it fired up, ran great. Yesterday I went out to start it and the battery was dead. I jumped it with another 12V battery. It starts and runs fine, until I unhook the "jump" battery. The second I pull the jumper cable, it dies. Any suggestions?