First off, never disconnect the battery from the charging system when the vehicle is running. It will create other problems. The voltage will spike and could fry your coils, electrics, and regulator diodes without a battery reference. If you were getting 13.8 volts when idling the bike was charging. If it went lower when reving up, you probably had a bad connection at the regulator connector, fuse box or any of the other high current connections. Test the battery now with the meter and see if you still get 13.8 idling, if not, you have a blown fuse, regulator/rectifier, alternator or bad connection. Sorry I can't help any more than that right now.
When checking fuses, don't rely on visual, test the fuses with an ohmeter or test light.
To comment about disconnecting a battery, a friend of mine was at his cottage and didn't have a battery for his boat (16 foot runabout). He used the battery out of his truck to start the boat then took it out of the boat with the engine running. Ran it for 20 minutes before it quit. When I checked it out, had to replace the tach, ignition coils, power tilt solenoid, regulator, low oil indicator and all light bulbs in the dash. Don't disconnect it!
