I am quite keen for someone to make a decent light-bulb for my old banger. It's got a Lucas E3L giving an alleged 60W at 6V. The 36W incandescent headlamp is pathetic, and unsafe. But so far, I have not been persuaded to buy anything better.....
The problem with LED headlamp bulb-replacements is that they are not bulbs casting light equally in all directions, as with an incandescent or halogen bulb. LEDs have a narrow-angle output. All LED headlamp bulb replacements I have seen cast the light sideways from a tower pointing from the base to the glass lens. I don't think any LED as a headlamp bulb-replacement will give a good beam pattern until one is made which replicates the omni-directional output of an incandescent light bulb.
To get an idea how a LED headlamp can be made to work well and give a good beam pattern, look here:
https://www.peterwhitecycles.com/b&m-hl.php
If you scroll down, you can see a test beam pattern, and I get the impression that a well-designed 6V 3W bicycle headlamp is better than anything offered for our elderly motorcycles (now that gives me an idea!). The secret is in the basic design. In these Busch + Muller headlamps, the LED is mounted at the top of the lens, points down and backwards onto the shaped reflector, and casts a carefully designed beam forwards. Most of the light is in the top of the flat-topped beam, little is wasted on the ground immediately in front of the cycle, and it's controlled for width.
My idea for a motorcycle headlamp bulb replacement is to have a single large LED pointing forwards to a small half-spherical reflector (sized to the width of the LED's beam at this range...) with its centre where the centre of the bulb used to be, so that it reflects the light backwards onto the headlamp reflector. Or perhaps two LEDs, one for low beam and another for high beam.
Anyone care to make a prototype?
Paul