carb for B31

[A Williams]

I need a new carb for my 1956 B31. I would like a Amal Concentric but do not know if it should be a 600 or 900.
The old carb is a Monobloc 376. I am thinking 26mm old carb was 1 inch
Where is the best place to buy? I have seen prices from £66 to over £150

[Jon Cull]

I would recommend Surrey Cycles, very helpful and knowledgeable. They seem to go to all the big shows and jumbles and have a very friendly collie dog.

[chaz]

according to Amal web site
http://amalcarb.co.uk/cf/vehicle/list/?manufacturer=B.S.A&vehicle=B31
376/2 rrp £197.58.
ive just ordered one for a B33 1947 and inc delivery £308..
if going 600 or 900 and you know what you want Wassells sell their version and a fraction of the price. trade of course but if you know someone with an account

[ANDY HIGHAM]

The monobloc is a far superior carb to the concentric

[Jon Cull]

The monobloc is a far superior carb to the concentric

Do you mind me asking what makes a Monobloc  superior to a Concentric ?

[ANDY HIGHAM]

1) The monobloc is a smoothbore design allowing better air flow
2) The body of the monobloc is stronger and less likely to distort at the flange
3) The monobloc has a replaceable pilot jet allowing both cleaning and fine tuning
4) The monobloc does not wear out as quickly as the concentric

Remember the design brief given to Amal by BSA/Triumph was for a carb that will give good wide open BHP figures and cost less than £5 per pair
The result was a cheap and nasty carb

[Greybeard]

And what's more, the Monobloc looks much nicer on a B31 
I would also buy a genuine Amal replacement though rather than a cheap copy. I've had three new carbs direct from Amal - 2 monoblocs (Ariel 350, Matchless G9 500 twin) and a 276 (52 Golden Flash). All three worked perfectly straight from the box. They also offer a superb after-sales service for parts and freely given advice.

Steve

[ducati2242]

I fitted a new monobloc to my newly rebuilt b34 . It started and ran perfectly ticked over like it had been there forever . I didnt even have to touch the idle screw never mind the mixture .