I can't find the picture now, but I swear I saw a picture of an early type (70-71) dual disc brake set up on a cb450. It could have been a 750 though, because I think honda used the same hangers for a couple of models. Again these are the early type hangers that do not swivel 360° or even 180° . Does someone have a picture or knowledge of how it was completed? I wish I would have bookmarked the picture because I don't know how they could have done it without lots of machining, i.e. welding new aluminum and machining and tapping etc..