The air sucked in by the engine passes through the venturi into the carburetor, it is a kind of constriction in the carburetor. Due to this tightening, the sucked-in air will flow more quickly, creating a vacuum. This underpressure causes the gasoline to be drawn in through the main nozzle and will be mixed with air.
The venturi controls the sensitivity of the carburetor, the narrower the venturi, the higher the air speed and vice versa. A venturi that is too small will result in poor filling of the cylinders at high rpm, and a venturi that is too large will cause problems at low rpm.
Under the related parts tab are the other sizes in which we can deliver the venturi.
These venturis are designed for the Spanish Weber IDF 40 carburetors and the American Empi HPMX 40 carburetors.
They can also fit the Italian Weber IDF 40, but check the external dimensions: diameter 40.9 mm, height 36.8 mm.
Useful information from Paruzzi magazine and from our YouTube channel :
Look for more technical articles on the page Paruzzi Magazine