Rider position, crown of road, tightness of head bearing, Varicocele, load of saddlebag distribution......any one of different angle of many different dangles could be your culprit. I find air pressure in tires can effect how easliy the bike will wander. It especially likes to go straight as the rear tire wears!
BTW I have a '05 RSV, 25k in miles.....just about ready to go for my 3rd rear tire.
Jim :formerly known as R*adVenturer