Motorcycle Repair: 1983 honda 550 nighthawak, stator coil, voltage rectifier

Question
Chris , I am a very new motorcycle owner I just bought my first bike at 41 yrs old , so this is all new to me , the problem I am having is that my battery is not charging ( it is brand new and I actually tried 2 new batteries that were trickle charged ) I tested the voltage rectifier and it showed a problem ( no ohms on the yellow and green) so I replaced it but the problem is still there even after recharging the battery again , the battery is showing 12 volts running and 13 volts when revedt to 3000rpms also the headlight does get brighter when reved I assumed that would mean the battery is charging but no such luck , any suggestions ? do I need a new alternator ?  

Answer
Hi Andy.
 The stator should be putting out between 13VDC minimum at all times.  It sounds like the stator coil is on the way out.  The fact that the headlight changes brightness, does mean that the stator coil is working, but, as I said, it sounds like it's on the way out.

Good luck.
FALCON