The fuel supply of the Vespa largeframe Models is always a bit problematic due to the small height difference between the tank and the float chamber level of the carburetor.
If the engine is converted to a different type of carburettor, its float chamber is usually higher than that of the original SI counterpart. In the case of very petrol-hungry engines, this can quickly lead to an undersupply, which leads to the mixture becoming lean and, in the worst case, this in turn can result in engine damage.
A central throttling point in the fuel flow is of course the fuel tap. The original tap has an average flow rate of just under 300ml / min. That would of course also be sufficient for the most powerful engine, because 300ml / min would correspond to a consumption of 18 liters per hour.VIDEO
With the PX, Rally, Sprint and similar models, however, as I said, it is more important to minimize the flow resistance in order to always have the highest possible pressure on the carburetor. To illustrate the flow rate, we have set up an experimental setup with three different petrol taps. We were also amazed by the clear result.
So far, the golden rule has been that for engines that are significantly more powerful than an original engine, a flow rate of at least 400ml / min should be aimed for.
Our new Faster Flow fuel tap not only doubles this amount, it adds another 100ml / min on top! So it has twice the flow rate of a conventional FastFlow fuel tap and an unbelievable three times the amount compared to an original fuel tap!
This makes it an ideal addition to all high-performance setups and offers a secure basis to prevent gasoline supply problems in the beginning.
The Faster Flow fuel tap is available in two versions:
- bgm PRO Faster Flow with manual reserve position (BGM3030)
- bgm PRO Faster Flow electronic reserve indicator (BGM3031)
version 1 with reserve position corresponds to the functionality of a fuel tap as it was installed in all PX models up to 1984 as well as all V50, PV and PK S models. When the reserve level is reached, manual switching of the fuel tap is necessary. Nice feature on the side: The FasterFlow tap has a larger reserve volume (approx. 1 liter) than an original fuel tap.
version 2 has only one open / closed position, but has a built-in float with which the reaching of the reserve quantity can be indicated via a control lamp (not supplied).
Here are some more tips:
- Do not use petrol filters with paper fleece, they almost halve the flow rate!
Our OMG fuel filter with plastic filter mesh offer the full flow rate without throttling!
- Always pay attention to the tank cap ventilation and clean it if necessary!
- Dell'Orto SI carburetor with the Float chamber cover of the Vespa COSA equip. This has a float needle valve with 5,2mm and thus an improved flow.
- Dell'Orto PHBH carburetor with a Float needle valve (including seat!)> 200 equip. Here, too, there is less resistance to the flow of fuel due to the larger bore.
- Use a fuel hose with internal wire reinforcement to effectively prevent kinks in the fuel hose (TS006)