Description
The 6413 range of jets for Dell Orto Carbs, The 6mm nozzles are exclusively used as main nozzle in the following carburettors:
PHBH, PHBL, PHBN, PHVA, VHSA, VHSB, VHSC, VHSH, VHST
Description
The main jet is considerably involved in the mixture preparation of the carburettor.
If it is too small, the engine dies off under full load and/or runs so leanly that the piston including 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.
Here it is important to find the ideal compromise.
To determine the correct main jet, it is first of all selected from the belly so large that the goal 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
