The headlight mounting bracket is fabricated from a piece of 1/4" x 2" 6061-T6 aluminum.
It is mounted using a clamp fabricated from the original USX logo plug that covered the opening at the top of the steering headset where a handlebar stem would normally mount. It was necessary to make a couple of mods to the clamp by adding a longer piece from a handlebar stem, a heavier draw bolt and a spacer made from aluminum tube.