Yamaha carries a 35W H3 (Part # STR4NK355001)

I was lucky to find a parts guy that knew what was on his shelf. He told me that this bulb isn't listed as a 35W on their microfiche, but 35W is standard equipment on some of their bikes' lightbars. Sure enough, the box says 55W, but the bulb inside is 35W.

Ron Turner Cycles

The Triumph dealer sent me to the HD dealer.