Twin carbs for 850 engine

[coopertim]

I'm looking to tune DPU's 850 and want to fit twin carbs. My question is which are better? H1's or H2's? I want the mods to be in period and the car is a 1964.

Cheers Tim

[carbon]

H1s are better matched in size terms for a mildly tuned 850. However by 64 I don't think H1s would have been preferred option, I think most people tuning an 850 would be going for HS2's - this is a bit before my time so can't be definite on this point, others may be better placed to comment.

On a practical level the twin HS2s are miles better than H1s. Spares are much easier to get hold of for HS2s, there are lots of them out there second hand, and the HS2's don't have the 'cork seal' main jets of the H1 which either stick or leak...

So if you're fitting twin carbs to a 1964 850 then I would suggest HS2s is the way to go.

[docka]

Sorry to hijack but how can H1s and H2s be identified? I have a set of twin 1.25" SUs n an AEG 573 manifold which I'd like to put on my 64' 850cc traveller but I'm not sure which model they are...
Thanks

PS, DPU looks like a fantastic car, well done, love it.

[carbon]

The HS type SU carbs have a flexible pipe which runs from the base of the float chamber to the bottom of the main jet assembly. Where the flexible pipe joins the base of the main jet there is a plastic moulding in red or black.

The H1, H2, and H4 carbs don't have this flexible pipe to the main jet. The base of the main jet is solid metal and has a metal bracket that attaches to the choke lever mechanism.

Hope this helps.