i pried open the sheetmetal and removed the glass lens from a sealed beam and broke out the bulb in the back. Then went to Home Depot and bought a 12volt 20 watt halogen.. not a bare bulb. This bulb has a reflector built in.. looks like this:
Then used Permatex Ultra Blue (#77BR) and glued it into the back of the reflector.. then replaced the lens and glued around the perimeter. Since these bulbs get hot i silver soldered a length of wire to the rear, instead of using just soft electrical solder.
The headlight's original glass lens diffuses the beam.. plenty of light and cars see me coming.
Been working fine for a month.. i doubt it will burn out anytime soon but we shall see. For replacement i must trim silicone, remove the front lens, remove the bulb and spend $4 for a new bulb.