Vespa carburetor SI short air mixture adjustment screw SI carburetor Dell´Orto & Spaco

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Vespa Si carburetor air mixture adjustment screw

Vespa Conversion mixture adjustment screw bgm PRO for SI carburetors Dell´Orto & Spaco

Mixture adjustment screw bgm PRO for converting Dell'Orto SI carburettors with long hexagon mixture adjustment screw to short slotted screw.

This bgm PRO conversion Air mixture adjustment screw is used to use carburettors with a long hexagon mixture adjustment screw in older engines (with stud bolts to fasten the carburettor). It replaces the adjusting screw that is too long on new Spaco and Dell'Orto SI carburettors and enables the carburettor to be installed without problems.

Due to the shorter screw, the carburetor pan can be left in its original state!

Fits in all carburetors with a long hexagon mixture adjustment screw.
(Used ex works in the PX models from approx. 1989 and all new Dell'Orto / Spaco SI carburettors.)

Vespa SI carburetor air mixture adjusting screw bgm PRO, short- SI20 SI24 Dell'Orto Spaco

Carburetor air mixture adjustment screw too long?

A carburetor is also a wear part and sometimes it is just not enough to clean a carburetor, you need a new one.

Especially if you want a little more power and adapt your engine setup, you usually need a new, larger carburetor. Below you will find instructions for installing the SI carburetor.

Vespa SI carburetor

SI carburetor for Vespa

Today all new carburettors come from SPACO, even if it says Dell'Orto. New SI carburetors, regardless of whether they are from Dell'Orto or from Spaco, are always delivered with a long (brass-colored) hexagonal mixture adjustment screw.

The exception here are our bgm PRO Faster Flow carburettors - but more on that below.


Problem with the air mixture adjusting screw being too long

With carburetor pans for engines without separate lubrication, this presents us with a small problem, because:

  • the carburetors do not fit properly in the tub
  • if you've fumbled it in somehow, no rubber seal will fit on it
  • and it's hard to get off

With the mixture screw that is too long it looks like this:

And this is what it should look like:


bgm PRO Conversion air mixture adjustment screw

Now you could come up with the idea of ​​simply screwing the old, short air mixture screw into the nine carburettors. Unfortunately, this doesn't work because the threads on the new Lusso carburettors are different. Please do not try by force, the different thread pitches will destroy the fine thread in the new carburetor and make coordination impossible. Our conversion screw can help:

With our short mixture adjustment screw for slotted screwdrivers you can fix the problem cheaply, easily and quickly.

bgm Faster Flow carburetor

Alternatively, you can also do one directly bgm Faster Flow carburetor use if you are already ordering a new one, we have already planned the update here.

For the models without separate lubrication, the bgm carburettors come directly with the short conversion screw.

bgm Faster Flow carburetor


Carburetor installation tutorial

Vespa PX tutorial SI carburetor bgm assembly Scooter Center