Help with fourtrax 200d starting/electrical issues

Hello! I have a 1995 fourtrax 200d. I noticed after riding for extended periods of time, the lights would go dim. Also, if I turned it off and tried to start it again, it would have no power, and refused to start. It has a new battery that has been on a battery maintainer. It would seem like it has a problem with the charging system, however, if you let it sit for a while and cool down it will regain power and start with no problem. I disconnected the battery terminal, and when I put it back on and cranked the engine the terminals sparked. I have no clue if there is a short somewhere, or where it would be. Thank you