Hitchcocks Forum

Hi everyone,

I'm looking for some advice or thoughts on an alternative carburetor for my 1933 250cc RE bullet. It currently has a 275BC/1A AMAL on it, which is giving me many problems.

As a reliable alternative, I was thinking to install a modern Mikuni carb, or something similar for the time being. However I am not sure which one would be suitable for this bike.

Does anyone have any experience in this, or has done something similar? Thoughts or advice would be much appreciated.

Many thanks

Your carb looks to be from a Panther.?
I would give Amal a phone and see what they recommend as an alternative.
http://amalcarb.co.uk/carburettor-for-a ... r-958.html

List of fitments here as a pdf.

http://www.vincenthrd.se/Members/Amal%20Catalogue.pdf

Could you use a small AMAL Monobloc?

Or even a 24mm Mikcarb from a 350 Bullet? The latter are very inexpensive and spares very easy to obtain.

Hi, a 22mm or 24mm mk1 concentric carb would be about right. You can always drop Amal a line as they are quite helpful. Regarding jetting i've found that when going from the pre-monoblocs to concentrics it (jetting, slides) etc are generally the same. So if you have a 140 main jet (as an example) in your pre-mono, then a 140 in your concentric is what you'll need. Hope that helps.

Our hosts have pre-monobloc type Amals in stock , but as far as I can tell, 15/16" is their smallest, possibly a bit to big for a pre-war 250? Anything suitable in their used parts section?

I think I'd want the original carb reconditioned if at all possible, but you could also consider a Dell'Orto PHBL, which you can get in choke sizes from 20 to 26mm.

https://www.dellorto.co.uk/product-cate ... 0-to-26mm/

A.

The carb you have does not appear to be the correct one for your bike so would be pointless renovating it.
An Amal 274/012R which is 23/32" so not quite a 3/4" carb is more likely what was fitted.

I have a 1954 pre-unit 250 Clipper (ohv, iron head & barrel). I know this isn’t the same as yours, but there are similarities. Perfectly happy with a 24mm Mikcarb from a Bullet, so I’d endorse the previous recommendation about these carbs. Very cheap and easy to set up & maintain too!

1933 250 - Is that / would that be a 250 model B side Valve or a 250 model BO OHV