Battery not chArging how to test stator or regulator?

[mattstolte]

Battery keeps dying I kept replacing it only to figure out that it wont stay charged. This last ride yesterday while I was riding I tried to turn my light on and it won't turn on? So I'm.thinking stator or regulator is not working? How to do I test these to see which is at fault. Also have a aftermarket rev box I put on. I heard these make it harder to start? Is that true
2005 400ex

[jman7290]

When my Stator went out, my quad would not run nor start. It shut down while I was out riding.