Battery Not Recharging

All,
I have a 03 predator. I have been overseas for a while but I am coming home soon and one of my buddies is rebuilding it for me. We are having problems with the electrical system. Problems that I have tried to fix before but evidently I haven’t. The problem is that when you start the bike, it runs off of the battery for electrical power. It can not recharge the battery because of how much of a charge it is pulling to run the bike. When the four wheeler was new I constantly replaced the bendix because of the starting issues this four wheeler is known for. As of right now, I figure this could be one or both of 2 things. One-The battery is simply not recharging. Two-Something is not telling the bike to pull from the stator (or whatever it should pull form) on the bike once it has started. Honestly, I am an aircraft mechanic and not a four wheeler mechanic. I am just using logic and I hope I am not thinking too deep or missing something obvious. If anyone is a guru and might have an idea of some parts to through at it…please let me know. I really want to get this rolling before I get home so that I can enjoy the little time I get on American soil. Thanks guys!