BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: Denaro on 17 Aug, 2023, 15:40

Title: Replacement carb for WD B40
Post by: Denaro on 17 Aug, 2023, 15:40
Hi all,

I have a 1967 WD B40 in the  later stages of restoration, fitted with a 376 Amal carburettor that needs replacing.

Since the original carb is a 398 for a WDB40, is it a good idea to go for a 376 ?
And can anyone recommend the best main & pilot jet sizes ?

Many thanks
Dean
Title: Re: Replacement carb for WD B40
Post by: Mike40M on 17 Aug, 2023, 16:27
Have a 1967 B40WD (Danish) which has been fitted with an 376/244 ( from a 1960 Triumph T110 )
1 1/16" Pilot 25 Cutaway 3.5 Main 250 Needle 106 Needle position 4. (If my notes are correct)
Though the slide is rather worn, so a fresh one probably needs a smaller main jet.
Have planned to replace the carb with a Concentric as fitted to the Australian ones.
But as it has started to blue smoke more than my 2-stroke racebikes, probably a cylinder bore first.
When getting a carb, choose a left hand so you can adjust idle and tickle without removing the battery!
Title: Re: Replacement carb for WD B40
Post by: Denaro on 18 Aug, 2023, 17:41
Mike,

Thanks for the suggestions, I'll give those a go.
Good luck with rebore!