Citroen Specials Club - the club for all lightweight cyclecars

Hi can any one help I have not long got a Lomax 223 it is fitted with a nikki carb and still has points ing, system I am having prob's with bad flat spots on moving of this can be made a little better by pulling the choke out a bit it feels like a carb prob are the nikki carbs a problem any ideas. ? i have cleaned card out and prog,s jet is clean and working.
Steve stevet2323@gmail.com

Has it always been like this or as it just started doing it?

If it has always done it then I guess the carb is just not set up for the engine. I don't know what jets you should use for a Nikki on a 2CV engine but I would suggest that, as a starting point, you set it up as for a 1275 A series Mini - you should be able to find some info on that.

I dnt know if its always been like as i had only had it for a 3/4 weeks
thanks for your help
Steve

Then I would assume it's never been right. Did you strip it properly and remove the main jets from the fuel bowl and blow everything through with compressed air?

It is easy to adjust the idle mixture and the idle speed but this won't sort out the flat spots. What main jet is in there now? Check it against what the recommended jet for a 1275 A series engine should be and try that.

An alternative possibility is that the accelerator pump is not working properly. The fact the car runs better with the choke out suggests it isn't.

Yes i striped carb comp,blow it out checked that jets that could be seen thro, can be. Pump jet is clean and working I will check main jets for size as soon as poss. I have also been looking into electronic ignition 123 system
steve

Hi Steve,
Did you ever succeed in sorting the problems with your Nikki carb? I came across one recently and thought it might be fun to adapt a manifold to suit it and see what happens! If I remember rightly, the main benefit claimed for them when they were popular back in the '60s was the device that was intended to resolve the flat spot caused by mechanical opening of a 2nd choke on carbs like the 28/36 downdraught Weber. I don't think I ever drove a car with one fitted, so have no previous experience.

Does yours use a modded 2cv manifold or one made from scratch? Inlet still attached to the exhaust? That's where I intend to start. Chop the existing carb flange off and weld or braze a new plate with the correct stud placing on, then mill the top face in situ to ensure it's flat.

Any info/experience you've had to date would be most helpful. That way I'll (hopefully) avoid too many mistakes/remakes

Ian

Ian - I saw a Nikki carb at Beaulieu on Saturday. It looked as if it would bolt straight on to a standard CV manifold.

There was a guy selling 38DCOE Webers for £40 (like below). They looked very usable - I'd like to build a manifold using a choke for each side of the engine;

Geoff,
As a result of you comments I've just measured the fixing hole pitches quickly, and it appears that one is ok at 80mm, but the other is 5mm out. Just enough to make plugging and re-machining a bit of a pain, though certainly not impossible. I've not yet checked the relationship of the venturi between the Solex and the Nikki and their fixing studs. Sods law will surely dictate that all 4 holes would need to be shifted for good alignment to the standard manifold. I'll keep you posted. As far as jetting is concerned, the Nikki being Jap manufacture I anticipate that Mikuni may fit. So far I've not found a UK agent for Nikki, other than ones fitted on Briggs and Strattons which I assume to be lawn mowers and the like.

Is your second picture of the Weber installation on a 2cv one you've seen or found on the net? The manifold would be relatively easily made by "cut and shut" of a couple of standard inlet parts of the cv manifold.
IMO a better solution than 2 Dellortos stuck out on stalks!

You could make a plate in 15mm Aluminium and countersink the screws holding it to the Citroen manifold or just weld up the existing holes and redrill or cut off the existing flange and weld on a new one. As you say, fiddly but doable.

I have seen the Weber carb installed on a 2CV but the picture is from the net. The one I saw used a substantial part of the original manifold and looked like bends from a second manifold. It wouldn't be difficult to make it from scratch using gasket as templates for laser cutting and some stock exhaust bends. I think the advantage with the DCOE is that it is horizontal and can be tucked down in the vee of the gearbox mounts to give a low bonnet line. The one in the picture puts it facing forward near the reniflard but the one I saw had it mounted the other way facing towards the firewall.

Hi
sorry for delay in getting back to you been away.
yes I sorted my niki carb. give it a good clean bent a couple of rods and after 3 try,s seems to be fine.
I like the look of your carbs be interesting to see how you get on
Steve