We just got a piece of solid rod that is the same outside diameter as the inside of the steering column. Take the bars off, you may have to use a dremel to clean up a little of the weld so that the rod will slide down inside the column... get a piece long enough to go clear down to the bend behind the air box.
Drive the rod in(you can find one that is a nice tight fit), tack weld it around the top, and put your bars back on. I even think my brother found that a 3/8" drive Craftsman extension was the exact right fit.
sled_guy