Something must doing it. To state the obvious just in case you have missed something...I have a Radar detector on my bike which unless i physically turn it off, will drain the battery. Anything you have added to the bike may do that...Is the ignition switch left in the off position?...i mean all the way off....Do you leave the steering lock engaged?..Parking lights?...I dont mean to be treating you as a dumb bugger but we do things like this sometimes...well i have done. Good luck in your search.