Bad voltage regulator. Catch the moment when the alternator system is not charging (voltage is lower than 13v) during running engine and perform stator tests following Buell XB Electrical Manual to confirm if the stator is OK.
Tympanium Corp designed and built OEM Buell VR. Buell VR has horrible soldering on the board with issuffitiens wetting flaws. Actually whole Buell electric system is nightmare. Vibration and thermal expansion make the VR lost electrical connections in those bad soldering spots for period of time and this is what you see during the riding on you voltmeter. I do not know what is the reason of such crappy quality, but any cheap Chinese electronic board has better quality than this proudly made in the US junk. So if you are DIY guy find and install any another suitable VR and avoid Buell VR on any cost.
You can build simple mounting plate for non OEM VR http://www.badweatherbikers.com/buel...tml?1412502792