I'm looking for a 40 or 41 tooth rear sprocket for the GS500. I can't find a listing anywhere. I'm sure one must be out there somewhere. Maybe one for another model that would fit.
Sprocket Specialists (//www.sprocketspecialists.com) carries a wide range of aluminum sprockets, 32-74.
http://sprocketspecialists.com/html/suzuki7.shtml