I've wondered this for a while. The stepped swingarm bolt we have(or had for those who upgraded). Instead of enlarging the hole for the unstepped bolt from a Suzi, Why not bore and thread the original bolt after the stepped, threaded portion is removed(sawed or machined) off? Use a bolt of same diameter and fine pitch and lock threaded.Gets rid of the stress point and no need to enlarge the hole in the frame. If there is a way to get that hole off centered while drilling, I would probably find that way. Maybe others have done that action and end up with the swingarm being un-centered.