Hello all I'm after some advice please. I have a bsa b40 with a wd engine. She's been sitting for a while and the carb has all disintegrated. Could anyone tell me what AMAL carb it has fitted please so I can try and source another. From what I can see it's a 626 L but all the one's on the net seem to be L and three numbers.

Many thanks

Original Amals and modern Amals are stampled up differently. On yours, the L means left hand which refers to the tickler and usually, the pilot and idle adjuster screws as well, although yours seems to have the tickler on the left and and right side adjuster screws.  The 626, 6 means 600 series and 26 the bore, ie: 26mm

If you're buying a new replacement, all you need is a 626, decide whether you want left or right hand, state the jet sizes, slide number and specify that it is a 4 stroke carb as the 2-stroke jets  and needle differ. The 4 stroke dioesn't use a pilot jet in the base of the carb as there is a pressed in bush behind the pilot adjuster screw instead

I'd be certain your carb isn't seviceable before buying new as they aren't cheap any more. 

We are looking at the right side of carb so L(left hand) looks to be correct. No 3 throttle slide is quite normal. My guess it has worn out in the body and throttle slide as they often do. Buy parts or carb from a reputable Amal dealer as some seems to sell strange combinations of parts that may affect performance. During the years the carb went through a number of modifications and they may or may not work together and may affect performance. The 626 (26mm) has a smaller body then a 928 (28mm). Amal carbs are simple but the modifications and differences makes it to a whole science to get them correctly set up.

My opinion is when they are correct they work amazingly well

Do not pump the tickler. Press it down until you see petrol coming out. My guess is you can omit the choke slide and start he bike from cold, only using the tickler. Should be tested before first occasion.

Remember, 4-strokes often leaning out mixture somehow when opening the throttle. Thus the need for accelerator pumps or CV-carbs.

2-strokes don´t do this

https://amalcarb.co.uk/

https://accessories.hitchcocksmotorcycles.com/Amal-Carburettors

Hi just ring Surrey Cycles as I did for mine and they will sort you no problem

Thanks to you 3 that replied all that was very helpful. Is this Bush the only difference in a 4 stroke carb to a 2 stroke one? Could I get a 2 stroke one and swop my internals over?

Many thanks

The brass insert where the needle goes through the ventury are different One is square at the top the other is cut away I use the the premier type on my  cub The body uses a better alloy and the slide is coated  

43 minutes ago, naichuff said:

The brass insert where the needle goes through the ventury are different One is square at the top the other is cut away I use the the premier type on my  cub The body uses a better alloy and the slide is coated  

Would you know if I can put my brass round 4 stroke one in there? Would it work

Comprehensive

https://www.triumphclassicmotorcycles.com/CATALOGS/AMAL/Amal Concentric Carb Tuning.pdf

Covers the pre premier concentric types

Thank you all for your help. I had to bite the bullet and buy a new carb that Surrey Cycles kindly help me out with. Would anyone know rough setting to start will?

Many thanks 

Did you get stay up floats and aluminium needle ?

Float level is critical, you must get that right before anything else.

When adjusting the air screw, it is incredibly sensitive so use caution.

On 11/19/2022 at 2:19 PM, b40rt said:

Did you get stay up floats and aluminium needle ?

Float level is critical, you must get that right before anything else.

When adjusting the air screw, it is incredibly sensitive so use caution.

Good afternoon b40rt i call Surrey Cycles and said about a new carb he said you want the Amal Premier Alloy Mk1 so would hope I have at that price. Also would anyone know what the thread of the carb studs are? as they seem too short and was going to replace then with slightly longer ones.

 

Many thanks

2 hours ago, evo boy said:

Good afternoon b40rt i call Surrey Cycles and said about a new carb he said you want the Amal Premier Alloy Mk1 so would hope I have at that price. Also would anyone know what the thread of the carb studs are? as they seem too short and was going to replace then with slightly longer ones.

 

Many 

I have Managed to find a kit with the longer studs. Could anyone give me some advice on the best place to find some metal mudguard? My front is 4 inches and rears 5 and a half. Look everywhere on feked British bike bits...

Good afternoon all. Could anyone give me some advice on carb jetting as I seem to have a real flat spot when cold I'm run 106 120 140 main

 

Many thanks