Modern Vespa

I want to squeeze some more performance out of my smallie, its a primavera 125, w/ a plug and play DR 130, 19/19 carb and a snail polini exhaust. I was thinking about the malossi reed valve manifold and the PHB25 carb it comes with. I have questions how to jet and how to specifically tune. I;m a newbie

the reed just bolted on will not make much difference as the rotary valve is still present.

as for a larger carb, fitting a bell to the 19/19 will allow it to flow about as much air as a 24. so for the cost of the bell and some jets you could experiment.

I cant tell you about the Malossi setup but I went with the SIP Series Pro Polini reed manifold and Dellorto 24. It was for my ET3, Polini 130 kit, Malossi snail shell exhaust, SIP touring lightened flywheel. My 19/19 carb was shit and temperamental so I needed something better since my wife was riding that. I had to drop the motor to install everything and it came with its own Polini proprietary nuts (dont forget to blue loctite them!). After that I needed a throttle cable adapter for the sharp bends on the carb and the rest was jetting guess and check.

As far as jetting goes, the simple version is you jet the main first and then clean up acceleration with the needle or the needle height. As far as what jets/ needle you will need, thats on you as each setup is different.

I'm not familiar with the "bell"

Can you send me a link for the throttle cable adapter? So I can get an idea what you are talking about?

And thanks!

Google carburetor bell mouth adapter

This helps route the cable and eliminate kinks/friction. You may need a longer throttle cable too!

there are a few bell-mouths available now for the 19/19.

AF Parts
OopsClunkThud

Here's a thread on the topic: Bell-mouth intake

In general the sharp edge at the intake of the stock vespa carbs reduces flow by ~30%. the bell smooths that transition to get that 30% back, or as much of it as possible.

How much more do you want?

That setup should be good for a solid in city rider and a legit 55-60 on a two lane.

You want more in town? Down gear. You want longer legs for top speed up gear.

You want a fire breathing monster? Well... that's doable. Money, know how, and direction.

-g

Thanks everyone!!