Get a volt meter and put it on yer battery. Should be charging at 14.5 volts (dont have a service manual at the moment) I couldnt tell you how to check the regulator without a service manual. do a google search. Make sure yer battery is charged fully or brand new before you do these tests. Its possible to have a brand new battery thats bad.
2010 KLX250S-Full FMF-Rejet-UNI-KX450 graphics
2008 KFX450R-Full Yosh-K&N-DG-ITP-Douglas wheels
2005 Brute 750-Full Big Gun-Rejet-K&N-ITP
1985 Bayou 185-Stock-
Kaw Valley Racing #68