I can fully charge the battery on my TB 400 and after 2 hours of riding it is so dead that the bike misses because everything is pulling from the alternator.

 

I would change out that battery. You could do a couple of things first. First, disconnect the ground side battery cable in hook a non-powered test light...if it lights brightly, you've got some sort of current draw. Also, you can charge up that battery, leave it disconnected overnight, and use a volt meter to see if it retains it's charge. Walmart sell the replacements cheap. Are you using a winch, or aux. lights?

 

No winch or aux. lights. I run the headlight all the time just for safety. Thanks for your reply.

 

If the battery seems OK, the first place to look would be the voltage regulator. It is the little box with wires coming out of it (that sometimes pull loose) on the front of your quad. Just be sure all the wires are attatched securely.

Farmr