Motorcycle Questions? Ask a Mechanic.
Hi and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, proposed preliminary checks (if have not been done):
As long as the battery is fully charged, then the Vulcan would start and run with or without a regulator. The burn marks as shown in the picture of the regulator would be indicative of a faulty regulator (least likely), excessive charging current (likely) and/or a loose terminal/pin (most likely). Either way, it would have no direct effect on the no-start nor with the no-run issues.
Please post back results / observations of the above once tried.
My next post would have been to jump the ignition switch's yellow/red and then the junction box's white/red to the Engine STOP switch's red wire and attempt to start at each try.
Still, I understand thus let me re-open the question by opting out.
Good luck with the Vulcan.