It's not the large stuff that stops a carburetor. It's the small stuff. Jets are very small. It does not take much to plug one up. Air and gas need to be clean.
You need to also remember that small grit ends up in the engine and will wear away the cylinder walls and rings. You need a proper air filter on any engine.
That's not to say you can't use the trumpet. It needs a proper filtering media on it. I would say that there is not much surface area though with the trumpet.
Those who are using the FZD (Chris) can weigh in on what they are using for a filter.
John

Thanks John. I know Chris uses the RamFlo filter and since they are based in the UK I'll probably go with one of those.

Matt

I fitted a RamFlo for all of the reasons above plus where I live (semirural) it gets a bit dusty from time to time. These foam style filters need attention as well because over time they deteriorate and bits of the foam can end up getting sucked into the inlet tract. Having said that, I've successfully used them on other cars for years without trouble.
The best would be a tuned horn (another subject entirely) with a large area paper filter around it. Unfortunately though, we have little room to play with.
Chris

Chris, when you bought your RamFlo, did it come with any fixings? All mine has is a single M6 bolt, which is neither use nor ornament. I've found some M5 bolts which, when cut to size, will do the job, but I was wondering what you used for a gasket?

Cheers,
Matt

Matt,

Like you, I just got the filter, backplate, wire housing and clamp. I cut my own gasket out of standard gasket paper and shortened a couple of M5 bolts to attach it to the carby. I probably should chamfer the washers so they don't protrude into the airstream, but I think the horsepower gains would be trivial

Sounds like you are getting on with it - excellent

Chris

PS: Maybe we should ask one of the moderators to consider making this thread a sticky as well - there seems to be a bit of interest out there.

Thanks Chris. Looking on eBay there seems to be plenty of people selling gasket paper, so I'll get some ordered and I'll make my own. As the RamFlo is going to be a Christmas present I'll have to wait for Santa to deliver it before I can bolt it and the carb to the car - something to look forward to. At least it gives me some time to sort out the bolts and the gasket.

I'll let you know how it all goes.

I agree with you about making this a sticky, as plenty of people seem interested in the carb (although perhaps less so when they find out how much they cost!)

Matt

Should be able to get gasket paper at any auto parts store. Comes in different thicknesses. Machined aluminum can use the thinner gasket. Steel flanges to aluminum should use thicker gasket material.
John

If anyone is feeling flush, someone is selling a pair of 32/28 carbs on eBay:
http://www.ebay.co.uk/itm/TWIN-DELL...343&pid=100015&prg=1006&rk=1&sd=251213342258&

Matt

A reconditioned pair of DCOEs on a manifold would cost about the same. Yep, FZDs are expensive, but they are a quality unit. All that said, I won't be bidding
Chris

Hi Folks;
For those people looking for throttle linkages, with ball-joints, try the SU Carburretor site (or Burlen--they are now the manufacturers of SU carbs)--go to the 'SU Carb Spares' page and then onto:- Linkage and Connections. they sell throttle-link rods with a ball-joint at each end in a variety of lengths, from 4inch to 8inch at about £11.00p each. I have done business with Burlen on a number of occasions--no problems at all.Hope this helps one and all.

Old thread, but I'm just now taking the plunge. I bought a set of FZD 32.28 carbs out of a Mini. I'll rebuild them both, get one installed in my '70 Lusso and sell the other one off.

I haven't seen the linkages on these yet but I'm sure I'll need something to get them connected up. TBD.

On the air filter - why can't (or shouldn't) I just make up an inlet to use the stock paper filter? I don't see anyone doing this so there is either an aesthetic reason or a performance one. I can machine up a collar for the FZD and maybe a new cover for the air filter and hose the two together?

Also, I have no idea what jets are in there. Chris mentioned how his arrived, but I have yet to find anyone selling tuning kits of jets for these.

Hi
do your carbs have all the bracketry for choke and throttle cable connections?
Have you got a method for holding the outer throttle cable on top of the air box?

I have an FZD and these issues are something I need to consider and any advice will be most welcome.

Many parts for these carbs are no longer available.....so time sharpen my home made design pencil....

I've got an FZD to fit at some stage. But can someone explain what the numbers refer to (mechanical novice here)? One must be jet size?

I know the recommended one is a 32/28, but mine is an FZD 32/26. What's the difference?

Thanks – Tim

Hi Tim,

My understanding of this is that the first number (32) refers to the diameter (in mm) of the throttle base and the second number is the minimum diameter (in mm) of the main venturi.

The system only works for single throat carbies (eg: Dellorto 32/28 FZD) and double throat carbies where both throats are the same (eg: Weber 40DCOE32). When you have a progressive system with different sizes throats (eg: Weber 36/28 DCD) it only refers to the throttle body (throat) diameters and not to the main venturis.

For street use, our two cylinder engines will cope with either a 26 or a 28mm venturi.

Chris

Thanks Chris. Looking forward to setting it up.

Tim

Bambino said:

Thanks Nigel - I appreciate your opinion.

The carby is equipped with the following:

132 main
190 air corrector
50 pump
48 idle
6747-8 emulsion

Do you know where I can get parts?
If possible, can you please post photos of your set up?

Chris

Click to expand...

Chris, did you end up changing any of these values? Is this a good starting point?

Mark

Hi Mark, These were the settings that I ended up using and the car performs very well. Chris

I'm getting pretty close to wrapping this up. I have the FZD 32/28 rebuilt and installed on the engine. The linkage was a royal pain and I'm still not thrilled with it. I'll probably end up making a new rocker arm assembly to replace the one on the engine, something that pulls more directly on the Dellorto throttle arm.

My Dellorto has an angled cast inlet which I was hoping to use but it looks unlikely it will work. The carb has a vent hole at the top of this which I'm not sure where it goes. Anyone have any ideas? There are three holes in the inlet of the carb; two are bolt holes and the third, on top, is an air inlet for something. Where should this go? I've circled it on the cast end piece.

Also, where do you run the vent hose from the valve cover?

Hi Mark,

I also have one of those original Dellorto air filters and it's a pain to fit because of the angle. I ended up fabricating a 90deg angle piece which adds another bend and length to the air passage.

The inlet that you have circled would seem to be for the crankcase gas recirculation - a rudimentary form of pollution control. I just bunged mine off and directed the crankcase gases down the front of the motor and onto the road
Sometime I should do it all properly with appropriate diameters of tubing.

I currently have my FZD stripped for cleaning. I didn't do this when I got it - just checked the jets etc., bolted it on and took off down the street. If there is any interest, I could take a heap of photos of the 'rebuild' and post them in a new thread much like the IMB one I did a while ago.

Chris