Modern Vespa

Greetings esteemed and knowledgeable ones.
I have recently come into the possession of an LML 125 reedvavle motor. The engine itself is as standard as can be with the exception of a 3 port 150cc barrel. However the carburettor was not included... would anyone here know the correct jetting stack to use? The engine will be run as is with a standard exhaust.

There isn't even a carb body on this at all... so I'm stumped and looking for the wisdom you all hold.

Many thanks in advance

This may help!

Standard carb is SI 20/20

The stock Stella idle jet is 40/130.

The stock Stella Main Jet Stack is:
140 Air Corrector (on top)
E3 Mixer (DO NOT MISREAD THIS FOR A BE3)
94 Main Jet (small bottom piece)

Stella 150 stock jetting:

130/40 idle
140/e3/94 main jet

EDIT: posted a few seconds late. Previous post wasn't up yet when I went to respond. Either way.. confirmation on that jetting.

thankyou everybody who responded. Armed with this I can now recommissoon the engine into a worthy chassis.

I really appreciate the help here everyone

Two things.

First, if you are jetting from scratch, I would use a BE5 mixer instead of the E3. They are roughly the same in terms of midthrottle richness, but it is easier to see where the BE5 fits into Dellorto's scheme. Also, I have a theory that the BE5 (4 holes in the waist section) does a better job of emulsification than the E3 (2 holes in the waist section).

Second, if you can get away with it in the UK, you really should replace the stock exhaust and its catalytic converter with a perfomance box exhaust such as the Polini. Doesn't do much for top speed, but a very noticeable improvement in midrange power. If you do that, the jetting stays the same except you will need a main jet in the 100-102 range.

Enjoy.