I've got an '02 Sportsman 400. Recently I put a new battery in because the old one went dead, and would no longer hold a charge. Anyways, put the new one in, worked great. After a couple rides though, this one went dead too. I charged it back up, and it works fine again, but I know it's gonna go dead again if I don't keep charging it. I know that wheelers don't have a conventional alternator to keep the battery charged, but what exactly do they have, so I know what I should be looking at. Thanks for any help guys.

 

check the voltage at the battery it should be around 13.5 to 14. if not heres what i had happen on mine. the voltage regulator is up front down by the radiator there is 4 wires coming out of it ya got to take the rack off and the plastic bumper and the plastic shroud. check the wires carefully mine had one coroded into where it went into the connector it was the red wire. put a new connector on it plugged it back in and its charging fine. this is a problem on older machines. the tech at the dealer told me he had repaired several older units hope this helps

 

it is likely that your problem is a voltage regulator like said by Colt2245p...

the charging systems on the atvs are stators.

 

Just a clearification for this test, the engine needs to be running at mid rpms, with no lights on.