AJS ECO-1 Headlamp Bulb

Does anyone know if I Can I fit a BA20D LED bulb to replace the very dim 35/35 existing one please?

Technically yes, legally probably not as I do not think any are sold that are approved for use. Do you have a particular bulb in mind?

My bike uses the same type, and it is very dim.

The problem is most LED bulbs though only have a single setting. I found one in Hong Kong on eBay that simulates the 35/35W bulbs, so in dipped beam mode it lights on one side, and for full beam on both sides. I never got to try it at night, but it was definitely much brighter, in low light road signs were bright, which they never were with a normal bulb.

But looking at the headlamp is just created a bluish mess in the middle of it rather than a big disc of light, especially with the reflector being a dull yellow colour from the 5W 'sidelight'.

I also started to notice a flicker to it which got annoying so I switched back to a halogen bulb. Maybe when it gets dark and I need to go on an unlit road I will switch back, but the way it failed to fill the reflector makes me wonder how well focussed the beam would be. I will probably look to find an LED for the sidelight too though first, just to fill the headlamp and give me greater visibility in daytime that I lost with using an LED.

Yep, that's the trouble with changing bulbs . The filament position has to be compatible with the curvature of the reflector. I tried it once and illuminated the whole countryside but created a black hole immediately in front of the bike.

I think the problem is that LEDs do not spread the light wide enough, so you need a bulb with enough LEDs around it to send the light in every direction. With my bulb it just has one LED on each side, so it only hits part of the reflector.

That said, I still reckon it will be better in the dark because a 35W BA20d is so awful and underpowered that you get a blackhole anyway. When dipped you can see just in front of you, but in full beam it dimly lights the countryside but as it is the same wattage not enough light is left to be focussed down in front to have any noticeable effect.

The best solution if you are planning on riding a 125 in the dark, and for long enough to be worth the effort, is to leave the headlamp alone and add some LED spot lights. These are relatively inexpensive and do not need much extra power from the bike, but will do a far better job than any replacement LED headlamp bulb on full beam anyway.

Being seen and seeing ahead are two different things. LEDs seem very directional so no amount of them are going to work . A conventional filament lamp throws light in all directions but the parabolic shape of the reflector captures it and projects it in one directionhttp://i.imgur.com/uqwnAdb.png.