SIP 3.0 valve for SI 27.23 carburettor for Vespa 160 GS/ 180 SS

Description

SIP 3.0 carburettor valve for Si 27.23 for Vespa 160 GS/ 180 SS, CNC machined, hard anodised Numbers (for comparison purposes) 5963.3 (DELLORTO) VESPA 160 GS (GS4) (D) 160 VSB1-2T 2T AC `62-`64 VESPA 180 SS Super Sport 180 VSC1T 2T AC `64-`68 The throttle valve limits the air flow to the engine. Its opening degree is determined by turning the throttle knob. The more it is opened, the more air can flow through. Some throttle slides have air pockets on the upper side and cut-out sections (so-called "inserts") on the lower side. These add extra air to the petrol mixture and make it leaner as a result. Slides with a flat bottom do not add extra air and are therefore ideal for compensating for a leaner mid-range. In order to comply with the emission values required for the new PX, the SI carburettors currently available are equipped with a throttle valve with two additional air pockets. This smooths the mixture so that partial load pinging and piston judging can occur on tuned engines. The solution to this problem is to replace the throttle valve, which is often equipped with a throttle valve without air pockets (e.g. part no. 84.920.400). Conclusion: Throttle valves are often overlooked when tuning carburettors and are the icing on the cake in SI tuning.