The DELL'ORTO 5mm jet is installed as the main jet on the SHB/PHBD/PHBG. With the PHBL/VHST carburettors they function as idle jets. As
the main jet, it is responsible for making a certain amount of petrol available for premixing. As an idle jet, on the PHBL/VHST carburettors, it
primarily affects the lower and middle rev range. With all tuning measures, no matter how small, it is necessary for the size of the main jet to be
raised, as they mainly impact on the middle and upper rev range.
Please take notice that we exclusively use DELL'ORTO jets. It doesn't make sense to save a few pennies and use reproduction jets. Those
who have tunes carburettors and found the actual jet size does not correspond to the number engraved on the side, know what we're talking
about. If 105 is on it, then there'd better be 105 in it! Anything else is a cheap trick.
The size of the jets increases on the basis of one, two and three stages and covers the 30–195 range. The jets get increasingly richer. Simply
attach the corresponding size to part no 4010. The 50-72/ 75-98/ 100-122 jetting kits contain 10 jets and are an ideal basic programme for any
tuner.
Conclusion: A selection of main jets is absolutely compulsory for every scooter driver.