which carb i shout use with this engine?

[alapimba]

Hello

My engine has this specs:
650cc,
35/75 camshaft,
-2mm head,
28/35,7 valves,
4kg flywheel,
record monza replica exhaust.

Which carb do you recomend for this engine? it's a street car, no race so i'd like something that let me use it in trafic and can idle well but yet powerfull.

At the moment i have a 28imb but i can't tune it i believe because it's leaking air somewhere or something like that, so if i'm going to fit another one i'd like something good yet not very expensive because the budget is low.

I have been thinking in a weber 32 dcof, but i heard it's not worth a double carb for my engine and a good choice would be a single dellorto (which one?).

let me know which carb would be good for me.

THanks

[hudsonhenry]

Without any shadow of a doubt a Dellorto FZD 30/24 or 32/28 Might be hard to find and they are getting very expensive when you do but the perfect carb for the tuned aircooled engine.

You could also try an SU, one of them, possibly an HS2 ( but I cant remember for sure), fits the FZD inlet manifold

Nigel

[alapimba]

what means teh 30/24 and 32/28?

Whats a fair price to pya for one of this carbs? i always see them at 300 400 500€...

[dajwid]

Thats the price 

As he said, they are getting expensive. Why not just replace, repair get the carb you have serviced. Much simpler if funds are tight.

As soon as you start modding you need very deep pockets and a very understanding wife

[alapimba]

eheh i'm at the end of the expenses with the engine so i didn't liked to dont' use all ther other performance parts fault of the carb
which diference will make a decente 28 imb vs one of that delortos?

[ChrisRLewis]

Just to add another suggestion, if you can find one, is the 'Reece Fish' carburettor. They were very common in the 70's and were highly rated for motors below 1000cc.

[alapimba]

it seems that reece fish is even harder to find 

whats your opinions.. the 300-400€ of a delorto is worth the diference from a weber 28 imb? that cost 100€?

for the looks the best would be a double choke that costs the same than one dellorto but it seams no one mentioned them so they are not worth in this cars, right?

[Rusty's Uncle]

In my opinion you were doing the sensible thing by getting the engine going using the 28 IMB carb and I can think of no reason why it should not run well with the right air jet / main jet combination. Apart from being hard to get the various carbs you can end up paying well over £100 just for the manifold & fixings. The twin choke Weber carbs are a bit like having two IMB carbs bonded together with a progressive throttle arrangement. So if you cannot get the jets right on the single choke IMB you would be just multiplying your problem by 2 as you will have twice as many jets to sort out  [-/

[Darrell]

I agree with Hudson, the FZD is more stable than the dellorto/webber 40's and with bigger valves it will benefit from the bigger FZD.

The standard carb leaves the engine breathless, thats what I found

[hudsonhenry]

The main advantages that the FZD or the DCOE twin chokes have over the standard carb is choke size and an accelerator pump (or two for the DCOE). A bigger venturi allows more air to flow (but too much is as bad if not worse than too little) and an accelerator pump which gives an extra squirt of petrol when you put your foot down ( the air in a carb travels faster than the fuel so when you accelerate hard with the standard carb it can hesitate while the fuel catches up with the air, if there is a pump, the extra shot of fuel gets rid of the hesitation).

Don't underestimate the standard carb it does quite a good job, but it can be improved on.

There are loads of motorbike carbs available for next to nothing, if you can fabricate a simple manifold you could experiment. Any aftermarket carb will need professionally setting up, ideally on a rolling road (dyno) so you need to factor the cost of this in.

[DEYAN IYI]

The double barrel progressive carb is the perfect choice between sport and street. I read that is not theoretical proved why the double progressive is better (more powerful) than single throttle under the same conditions and airflow on high rpm. If you want it more sporty than economical, find yourself with a mechanical instead of vacuum moved second throttle. Manifold... hmmm... (Panda 30, 126 Bis, Cicuecento 700... types of carbs).

The easiest carb to fit is something like Weber IBA 32 or Weber 32 ICEV: 127 1050/ PANDA 45; RITMO 60; UNO 45/55/60; SEAT: IBIZA JUNIOR; PANDA 45; Go to the scrapyard and look for it [-/

Manifold ... too much money for such a piece of junk... You can do it as well. Shape those two parts and weld them together. You can do it even better without the pooty turbulence zone in the adapter with smaller screws like this one underneath.

[alapimba]

On mu fiat 600 i have a weber 32 dmtr. Is that the carbs that you are talking about? I also have a weber from a fiat 127. 30 icev if i'm not wrong

[DEYAN IYI]

Well, great!:D Yes, that's what I mean.

Take a look at this list.

[Rusty's Uncle]

Probably did not make it clear to you and Darrell but what I meant was get the engine all sorted and running sweet with the 28 IMB then you would be in a good position to experiment with other carbs & jet trials would be useful if you go down the twin choke Weber way. I think that the Dellorto FZD has more of a reputation as a track or street racer but the Weber twin choke can have that split personality , sweet around town but a beast out on the highway  [-/
DEYAN my man you have just hit on one of my latest focas areas , that turbulence on the inlet , I have got lawn mower engines with a better flow pattern than the Fiat air cooled engines. Plans for an improved inlet are on the drawing board right now  [-/
Forgot to mention the pics I posted so Weber 30 DIC & Dellorto FZD 32/28

[gsxr126]

That's a very clever idea DEYAN [-/, i never thought of making up a two piece inlet manifold. I'm thinking an offset design so you can avoid the restriction completely