Dellorto Item number: 2504034
Dellorto
1 Rating
4,00 €*
available immediately
Shipping weight 0,001 kg
The main jet is considerably involved in the mixture preparation of the carburetor.
If it is too small, the engine dies off under full load and/or runs so leanly that the piston and cylinder overheats and a cylinder damage would be the consequence.
If it is too large, the mixture is too rich, the engine runs very unevenly and can only deliver a fraction of its possible power.

To determine the correct main jet, it is first of all selected from the belly so large that the target is an engine that stutters heavily under full load. Of course it needs some experience, but a nozzle is also quickly changed.

Once you have found such a nozzle you mount a smaller nozzle until the engine does not stutter under full load any more.

This way you have already an ideal basic lubrication which ensures that the engine does not get too little fuel under full load, which it also needs to cool the piston and cylinder. The Dell'Orto carburettors in conventional slide valve design, where the main jet is positioned directly in the float chamber (no SI carburettors), use as:

secondary jet 4mm / 5mm

main jet 5mm / 6mm

jets.

The 4mm nozzle type is used exclusively as a secondary nozzle, although it would mechanically fit into other carburetor types of Japanese origin as a main nozzle.

Used in the following carburetor types as a secondary nozzle:
PHBN, PHVA


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Ingo K. from Buchholz 06/24/2025
Carburetor jets
Secondary nozzle for
Dellorto PHBN, Dellorto PHVA, Dellorto PHVB
for carburetors from the manufacturer
Dellorto
Powerjet nozzle for
Dellorto PHBH
Thread
M4 x 0,75
Head diameter
5 mm
Thread length
4 mm
Total length
7 mm
 
OEM numbers (for comparison purposes only)
Piaggio:
AP8222685
Scooter Center:
2504034
Dellorto:
1160034_02
Peugeot:
753131
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