Assuming a full bike, frame, tires, and engine. Probably have to make a custom shelf that is capable of 200-300 lbs. (just to be safe). Mounted to the wall studs and a safety cable would be good to keep the bike from coming off the shelf by accident. Could cut a good amount of weight with a fake engine. Not sure if they have Styrofoam or plastic mock up small engines, like they do for V8's. Though gutting (no crank, rod, piston, cam, or valvetrain) an old engine would drop a good amount of weight. If it just for display.