I went on a five hour ride today and probably about four hours into the ride while in some heavy shaded woods I turned my lights on and as soon as I did the engine shut off. I noticed that the rear brake light was not working after a few seconds the light came back on and I was able to restart my atv. Looking for ideas no what might be wrong.

 

That sounds similar to an issue I am having on mine. I have narrowed it down to somewhere in the stator area. Other things you can check are you battery fluid levels and your voltage levels. Your voltage should be around 13.5 volts when the engine is running. If it is not, you are not charging. Since your motor died, that, to me anyway, points to the stator.