Before you do anything, give all your fuses/relays a once-over to make sure they're seated well. Check your battery terminal connections and trace your grounds, especially the frame ground, to make sure they're not corroding or loose.
Then check to see if you have stored engine codes, which sounds like you will. Order you an ECMSpy cable off of Xoptiinside.com and download the program off of Buellmods.com - downloads section. VERY helpful for troubleshooting... In the meanwhile, you can use the wire jumper method to test for engine codes: Checking codes w/o ECMSpy