A suggestion for this issue is:
take note of the carburetor model that is (I suppose that if it is R11 1.4 it will be the Zenith If 32) anyway is written in the fuel itself and in the technical section of the car maintenance book.
With this information you go to a spare store and ask for a "repair kit for the carburetor mod ..." (if possible the one that brings the membrane of the acceleration pump, is the most expensive of the two, around about 25 or 30 euros)
then take an empty oil can and the short side as if you were to change the oil to make a kind of minibarreño.
Remove the car carburetor for it:
remove the air filter (and the housing of course)
disassemble the starter and carburetor accelerator cables, as well as gasoline and water tubes (eye with the water because it will come out so try to look for a plug for the tube before removing it).
Remove the screws that unite the carburetor from the intake collector, carefully that no nut or piece falls inside the collector.
Remove the carburetor seat joints to the collector and the plastic taco that goes between the carburetor and the admission collector if he will take it (I am not sure).
Once out of the car, you put the carburetor in the empty can, full of solvent or zotal, disassemble the carburetor, and with the help of a brochite or brush, clean it with care until nickel is nickel.
Be careful with the solvent because in addition to being flammable "place" that is to say the vapors get drunk so you better in a ventilated place.
And after all this, you proceed to mount the carburetor piece by piece, putting the new joints.
Finally, the carburetor in the car following all the steps in reverse order to how I have explained it.
Note: At first it will cost you a little to tear into the car, but it is normal since the Cuba is empty.
The adjustment of the CO (carbon monoxide) should do so in a workshop although if you have any mechanical colleague you can do it at the ear house and for the smell of the smoke of the car.
I hope I have helped you.