After storage, the dealer rebuilt the carbs and somehow hydrolocked the motor. They wouldn't stand behind it and I bought it as is.
"Wouldn't stand behind it" sounds fishy to me. After getting burned too many times with used vehicle purchases, I am inclined to believe that it hydrolocked multiple times and they couldn't fix the underlying problems due to a lack of comprehension on their part. I can't recall if we've already had this discussion on the board with you, but make ABSOLUTELY sure that the hydrolock cause is repaired, not just the symptoms.
Sorry I can't help much with the electrical problem. If you just want to test the radio, try finding another IS owner nearby, and swap radios. It will tell you whether it's your radio or your bike's system.