Dell'Orto Needle for PHBL/VHST D Type

D type Dell'Orto Needle for PHBL/VHST Carburetors

Partial load or half gas can be reached when the gas slide valve is 1/4 to 3/4 open. Jet needles and mix tube are responsible for regulating the gas in this range.

Needles

The needle can be adjusted with a clip in 4 different positions. If the motor runs fine with the throttle completely wide open, but stutters at half, then it's running too rich. You can hang the jet needle lower (move the clip higher up the needle) and so reduce the mix in this range. If the needle is already at it's lowest position and the mix is still too rich, then use either a thicker needle or a smaller mix tube. If your performance is too low at full gas then hang the needle higher. Needles come in a variety of thicknesses, lengths and grades. We recommend trying out several needle sizes to find which one is best for your personal tuning needs.