Correct name for bulb fitting

[bevanclark]

Hi folks,
Could someone please tell me the correct name/description of this type of bulb fitting ? It is a 6V 45W Marchal lamp with 3 locating pins spaced at 120 degrees and a single filament connection at the bottom - see image.

Also: is there an LED replacement ?

Thanks,
Bevan

[simon.holyfield]

What's the diameter of the cap?

[JohnnyBeckett]

i think it maybe a old bus or coach interior lighting bulb

[Pete.Silson]

Is this what you are looking for?

[bevanclark]

The bulb has a 2 cm diameter base. It is fitted to a 1929 Duciellier headlamp which a previous owner fitted to my BSA Sloper (it left the factory in 1929 without a lighting set.

I'd like to replace it with an LED bulb if possible.

[simon.holyfield]

The bulb has a 2 cm diameter base. It is fitted to a 1929 Duciellier headlamp which a previous owner fitted to my BSA Sloper (it left the factory in 1929 without a lighting set.

I'd like to replace it with an LED bulb if possible.

If you Google BA21S, you'll find folk selling LEDs to suit!

[bevanclark]

Thanks Simon .

That BA21S code is exactly what i was trying to find out. Google brings up images just like my bulb, although most are 12V. I have been musing on whether to return the lighting to dyno operation - my MDB1 dyno is not connected at present; it is running lights off a battery, so i could actually go to 12V if needs be. I'm not worried about authenticity since it isn't the correct headlight and the bike had no lights at all in 1929 anyway.
Cheers,
Bevan

[simon.holyfield]

It's all thanks to Pete Silson really.

Curious as to what headlamp you have, to use a bulb like that?

[bevanclark]

Hi Simon, maybe from a French vintage car ? Apparently period correct but obviously not BSA. The bike was exported directly from the factory to Hungary where it spent almost 90 years of its life.
Cheers,
Bevan,
Ps.
sorry everyone for the non-Ariel questions - this forum is a lot more active that the BSAOC one !

[ian williams]

MARCHAL ba21d double filament led

https://www.classiccarleds.co.uk/produc ... Q0tdvepIkr

looks like they come in either BA21S SINGLE or BA21D DOUBLE filament depending on what you want or want to setup in your headlight .

link for single

https://www.ebay.co.uk/itm/174779761634 ... gLWJfD_BwE