I'm working on my buddies 2004 sportsman 500. It won't charge. I can hook it up to my KQ and it will jump off no problem and run fine hooked up. When I disconnect the jumper cables it will die in about 30 seconds. I ohmed the 3 yellow wires on the stator and they ohmed all around 27-28ish I did the 1-2 1-3 2-3 combo on the yollow wires. I believe it shouldn't have that much resistance so I'm thinking the stator is shot. The battery voltage drops like a rock as soon as i disconnect the jumper cables from my kq. All the connections look good.

Sounds like the battery is dead , have you charged it up ?
Your stator seems to read high resistance between phases but they all read the same { good } , are you sure you weren't reading .27 ohms ?
if you have no grounds on any of the yellow wires { you did check for grounds ? } I would suspect the voltage regulator is bad , a lot easier and cheaper to try .

The battery is dead now since it's not getting charged. It's a brand new battery that was charged before install. Wouldn't it still run fine with a dead battery if jumped off?

No , it wouldn't run if the charging system isn't working and the battery is depleted.

Yeah, definitely an issue with the charging system. When hooked to my KQ it shows around 12.5 volts. And dies quickly when unhooked. That has me thinking the stator. I would think if its the regulator it would over charge wouldn't it? I went over the grounds and they seem good. I'll double check connections though.

Regulator can fail either way , over or under charging .

Connect an ac ammeter between the yellow and yellow/red. Pull start the atv. Manual shows at an idle should show around 7 amps.Resistance between the yellow stator wires should be around 0.13 between each other. Also do you have the regulator or ecm model? If it's the ecm model,they can cause all sorts of problems. Plus the 2004 ecm models were under the recall.http://www.cpsc.gov/en/Recalls/2008/...o-Fire-Hazard/

See that's where I'm getting confused, it has the ecu like the picture you attached, but also right under the headlight pod it looks to have a regulator. I'll get a picture of it when I get a chance and post it up.

If this { or very similar } is what you have under the headlight pod it's the voltage regulator .


Polaris Regulator Rectifier LR 390 120 PN 4010657 ATV | eBay

You're probably confusing the CDI with an ECM module that takes the place of a regulator/rectifier on some of the 2004 models. Look at the link that Yooper265 posted on a regulator. If you have the regulator equipped model,it will be located down close to the radiator. Most of the time it's a regulator problem on charging,not stators.Plus connectors are bad on these regulators about coming loose from vibration.