The fuel supply of the Vespa models with SI carburetor type is always a bit tricky. Due to the very small difference in height between the petrol level in the tank and in the float chamber of the carburettor, there can always be an undersupply of petrol. Especially when the tank content is approaching the reserve, the pressure difference is often so low that this is noticeable in a lean engine. In addition to the usual suspects such as a functioning tank vent, the fuel tap should not be clogged and the fuel hose length should be as short as possible without kinking the hose. To prevent the latter, we carry fuel hoses with a wire inlay, which effectively prevents the hose from kinking.
Another measure to optimize the fuel flow are the float chamber covers of the Vespa Cosa models. These have a larger float needle seat with a larger flow bore. In addition, the float needle is provided with a spring whereby too high pressure on the sensitive rubberized needle tip is prevented. This keeps the valve much longer tight because the pressure is not only distributed over a larger area but is also cushioned.
As a recommendable measure the drilling of the gasoline channel in the carburetor between float chamber and nozzle block proved. Here the drilling to approx. 1.8mm extend around always a sufficient flow to ensure.
The float chamber cover is available from DRT, Dell'Orto or Pinasco. All are the same design, but cost different amounts. However, the DRT kit comes with a float needle directly that needs to be added to the Dell'Orto cover.
(271221TW)
AI-translation
DE | €
