Scooterotica

Carb can it be done and how hard is it

So you want to fit a fuel pump (diaphram pump) to a Vespa engine (PX) with a standard carb?

There must be a good reason.......

because ive got a ported malossi kit with a cut and polished crank and all that goes with it and I think iggy from scootering as one fitted to his

A fuel pump is only required when you fit a biger carb that is sitting higher than the bottom of your petrol tank, you then run the risk of fuel starvation when your tank gets low. As your using a standard carb the a pump is a waiste of time and a lot of hassle to fit. It has nothing to do with performance. Have pumps fitted to my 210 mallosi and my 220 polini and it was a pain to get them to work right.

When I had a standard carb on my 210 it suffered from fuel starvation swapped to a bigger carb and a dellorto fuel pump. I searched internet for help and It was straight forward to fit.

the main reason is I think its the only way to stop the problem I have.. which is any less than half a tank when u give it the beans the engine will die then after about ten or so seconds it goes again ...now I no its a fuel issue cause with more than half a tank its fine ....... all was good till I polished all the ports wished I would of left it alone ... or is it something else.... ive just drilled a pilot hole in my tank cap to c is that helps ..ive tried 3 different carbs and its the same on all of them

soulboy wrote:the main reason is I think its the only way to stop the problem I have.. which is any less than half a tank when u give it the beans the engine will die then after about ten or so seconds it goes again ...now I no its a fuel issue cause with more than half a tank its fine ....... all was good till I polished all the ports wished I would of left it alone ... or is it something else.... ive just drilled a pilot hole in my tank cap to c is that helps ..ive tried 3 different carbs and its the same on all of them

forgot to add if I ride steady its completely fine doesn't miss a beat

Classic case of fuel starvation. Fit a fast flow BGM tap and this should suffice.

Its already got a sip fast tap mate

With the fuel line disconnected from the carb, what’s the fuel flow difference between a full tank and half a tank? I know most Lambretta folks quote “a pint of fuel a minute” is what you should see from a fast flow tap. There really shouldn’t be much of a difference between full and half a tank. What happens when you run the same test with the tap on reserve? Again that shouldn’t make a difference and if it does it points to something funny going on with your tap.

If all checks out with the tap I would think you should be looking at running a fast flow float bowl cap and needle. Plus there is a mod to be performed on the feed going from the float bowl to the jet stack that can restrict fuel flow on really fast bikes running an SI carb. Something like this:

http://www.sip-scootershop.com/en/produ ... +_12832540