What did I do? Well, I took the right mirror off and opened up the rather thick alloy handlebar inside diameter to accept the rubber mounting donut of a Ken Sean bar-end mirror. Of the two sizes provided with the mirrors, even the smaller of the two would not fit. After fitting the first donut, I concocted a design for a 2-piece delrin clamp, similar to the OEM bar end weights. Misery is the mother of invention.