Set of 5 POLINI 363.0003 cycle jets maximum and minimum DELL'ORTO 4 mm from 125 to 137 for DELLORTO SI 20 22 24 carburettors size increment 3 VESPA 125 150 160 180 200

Polini Motori presents the new series of jets for DELLORTO, KEIHIN and MIKUNI carburetors. The importance and the characteristic of the new production of Polini Motori main jets is the high manufacturing precision and the control carried out in a millesimal way on the measurement of the passage hole in order to guarantee a correct modification to the carburetion. The main jet acts on the carburetion mainly for the last three quarters of the throttle opening, but it still makes its influence felt even if in a less marked way starting from the medium openings. Modifications to the carburetion: Increasing the size of the jet enriches (fattens) the carburetion, increasing the quantity of petrol aspirated by the engine. Reducing the size of the jet impoverishes (leans) the carburetion, decreasing the quantity of petrol aspirated by the engine. An increase in the ambient temperature or an increase in altitude above sea level causes a lower density of the air, causing a richening of the carburetion. An incorrect carburetion adjustment with an excessive leanness (reduction of the jet size) causes overheating of the engine up to the point of seizure. An incorrect carburetion adjustment with an excessive richness (increase of the jet size) reduces performance, increasing fuel consumption and causing fouling of the spark plug. In addition to providing the single jets in the various sizes, Polini Motori has also thought of convenient packs containing 5 jets of various sizes for the most demanding tuners.