If you've ever seen a 60s-era American musclecar revving at a red light, you probably saw the front end twist from the torque. A long driveshaft and heavy flywheel mounted longways in a bike could have a similar effect, and I do remember people noting it when the K bikes came out.
 One guy said that BMW had apparently welded a sewer lid onto the end of the driveshaft.
 Bah. I knew after walking away from the computer for several hours with a reply open that I should have checked for updates in the thread before posting. Christian got the physica exactly right.