just picked up a 2001 Arctic cat 400 4x4 for $500. wont stay running with out jumper cables hooked up to it. when you remove the cables it then dies out after about one minute. Seems to me this is the regulator. could I be right, I dont want to drop $200 with out having better odds. Any help is great thanks. Also what about the Mag. on the coil?

 

I'd start by pulling the battery and either have it checked(walmart,autozone,etc), or hook it up to a charger for 12 hours. Then use a multimeter to check the voltage. Both charger and multimeter are money well spent in this sport. Also don't jump the quad from a car. If it is absolutely necessary, do not crank the car for the jump.