[Dr.Hess]

Find the half amp drain. As Rob says, start disconnecting stuff. Pull the faring off, go to the bank of breakers and start disconnecting one end of each one until the half amp reading dissapears at the battery. Then start following that circuit. Also try disconnecting the line from the regulator, which goes to the main breaker, if I recall, under the seat. If you have every breaker under the faring disconnected and still have that half amp draw, then pull disconnect the main breaker under the seat. If it still draws, then the only thing left is the starter solenoid.

I'm going to take a SWAG and say the clock/radio keep alive.

Something should be kinda warm to the touch too.