Jet needles and part-load tuning on the DELL'ORTO Carburettor

Together with the Mixer Tube, the Jet Needle regulates the mixture composition in the part-load or half-throttle range. Needles differ in diameter, length and pitch - and each of these properties influences the mixture in its own way. Basically, the thicker the Needle, the leaner the mixture. The longer the Needle, the earlier the mixture is enriched.

The Needle also has four Clip positions for adjusting the installation height. The higher the Clip is seated on the needle, the deeper the needle dips into the Mixer Tube - and the leaner the mixture becomes in the half-throttle range. If the Needle is already in the lowest position and the mixture is still too rich (recognizable, for example, by the four-stroke action when the Slider is half open), a thicker Needle or a smaller Mixer Tube should be selected.

The range includes all needles for the DELL'ORTO PHB series (X1-30 for PHBH, D22-50 for PHBL) in DELL'ORTO original equipment quality. Needles for the DELL'ORTO VHS series are also available (K2-98 for VHSB34LD/QD/38DD/VHSH30CS and D36-53 for VHST 24-28BS) - also in DELL'ORTO OEM quality.

Conclusion: Patient testing is worthwhile, because the Carburettor can only work optimally in the partial load range with the right Needle.