The three bumps are for an aiming machine. The pattern on those sealed beam lamps was so bad that the common procedure used in Europe of looking at ithe pattern projected on a wall didn't work. Many of the European Code H4 lamps have little U shaped mounting points atttached to a very thin metal rim for purposes of making them interchangable with glass lamps. Getting rid of the mounting points is easy with a Dremel. The result will probably look just like the rim on the lamp you wish to replace. As I gracefully age, and need better lighting, I find that it is harder and harder to ADD fog and driving lights to plastic front cars, and the wimpy "fog" lamp decoratuons on most new vehicles are a joke. Factored into my next car buy will be a good hard look at light mounting opportunites. May have to buy some kind of SVU thing which will accept an OEM of aftermarket light bar.
Bit of trivia, when the Fed Nannies were busy enforcing the "NO NON-SEALED BEAM" regulations for cars, making "Grey Market" importers, for example, PULL the expensive European lamps from high end European cars and replace them with JUNK (sometimes leaving the pulled lamps in the trunk, hint hint) the NANNIES were ADVOCATING the use of the same lamps in US motorcycles. One could buy European H4 units in many imported car shops "for 'off road' and MOTORCYCLE street use only" You can guess where a LOT of them ended up. My first pair of 7 inch "EC" lamps went into a 71 Volvo in
1972. Had them in all my later cars until the "aero" headlight revolution made it impossible.
Take a look at Dan Stern's site, if only to see what is availible. You might even send him an email describing your plight. He does some "custom work" I can't see, given the care we lavish on these bikes, not having a GOOD headlight.
