Yeah I figured that's why but wasn't sure. Regardless they didn't fit.It's not the diameter of your bars.
First of all, 7/8" and 1 1/8" bars both end at the same diameter...in other words, fatbars taper at the end to fit controls.
They won't fit your LSL bars because the -inside- diameter of the LSL bars is too small on the end. The LSLs bar stock is thicker so that they are stiffer without having to brace.
You can get clamp-style bar end mirrors or you can try shaving out the bars on the inside.