Have a 96 sportsman 500 4x4 that I just bought used,I put a new battery in it and when I run it,the batt goes dead after about 1/2hr of riding,now this is bad in itself but when the batt goes dead does this effect the 4 wheel drive and the fan??It seemed like I lost 4 wheel drive as soon as the Batt went dead Also how do I test it to check the 4 wheel? What could be making the Batt go dead? the Alt or the regulator?

 

Look at the voltage regulator,
see if theres any broken wires or loose connections

 

had same problem, if you leave that battery in their you are going to blow out EVERY bulb on your machine, spend 40$ on a Cycletron battery from interstate

 

what do you mean I'll blow every bulb,kukerdan? It is a new battery,seems like it isnt being charged back up?

 

Woody, it is most likely either the alternator or the regulator. I think it would most likely be the regulator, or the wires leading to the regulator. The alternator is under the side case, well protected from things. The regulator is that little box by the radiator with wires coming out of it. On my machine, you can see it from the front if you really look. Near the top, to one side there is a flange with a little box with wires attatched. It isn't all that uncommon for a stick or clump of mud to grab hold of one or more of the wires, and either tear it, or pull the connection loose. I would check that first.

What Kuderdan meant about blowing your light bulbs is that if your battery is plumb dead, and you get the alternator/regulator fixed, it will try to charge the battery as fast as it can, and it can send so much juice through the wiring, it can actually burn out the light bulbs. Charge up the battery at least somewhat before you run the machine after fixing it. This will protect the system from surges, and will prevent overloading the charging system from running everything plus trying to charge up a battery from dead.
Also, as the system voltage level drops, strange things will happen. The magnets that activate the 4wd will weaken, causing you to lose 4wd. Strange things may also happen with the rev limiter and the reverse override. The fan will also not work properly with low voltage, which may also not cause the overheat light to work properly. Basically, what I am trying to say is get it fixed before you go on any major trail rides!