Vespa conversion mixture adjustment screw bgm PRO for SI carburetors Dell'Orto & Spaco
Mixture adjustment screw bgm PRO for converting Dell'Orto SI carburetors with long hexagon mixture adjustment screw to short slotted screw. This bgm PRO conversionair mixture adjusting screw is used to convert carburetors with long hexagonal mixture adjustment screw to use in older engines (with stud bolts for carburetor mounting). It replaces the excessively long adjusting screw on new Spaco and Dell'Orto SI carburetors and enables the carburetor to be fitted without any problems. Thanks to the shorter screw, the carburetor bowl can be left as original! Fits all carburetors with long hexagonal mixture adjustment screw. (Used ex works in PX models from approx. 1989 and all new Dell'Orto/Spaco SI carburetors).
Carburetor air mixture adjusting screw too long?
A carburetor is also a wearing part and sometimes it is simply not enough to clean a carburetor, you need a new one. Especially if you want a little more power and adjust your engine setup, you usually need a new, larger carburetor. Below you will find instructions for installing the SI carburetor.
SI carburetor for Vespa
Today, all new carburetors come from SPACO, even if it says Dell'Orto. New SI carburetors, whether from Dell'Orto or Spaco, are always supplied with a long (brass-colored) hexagonal mixture adjustment screw. The exception here are our bgm PRO Faster Flow carburetors - but more on this below.
Problem with air mixture adjustment screw that is too long
For carburetor bowls for engines without separate lubrication, this presents us with a small problem, because:
the carburetors no longer fit properly in the sump
if you have somehow fumbled it in, no rubber seal will fit on it anymore
and it's difficult to get at it
With the mixture adjustment screw too long, it looks like this:
And this is how it should actually look:
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 new carburettor. Unfortunately, this does not work, as the threads of the new Lusso carburetors are different. Please do not try to force it, as the different thread pitch will destroy the fine thread in the new carburetor and make tuning impossible. Our conversion screw provides a remedy: With our short mixture adjustment screw for slotted screwdrivers, you can solve the problem cheaply, easily and quickly.
Alternatively, you can also buy a bgm Faster Flow carburetor if you are already ordering a new one anyway, we have already provided the update here. The bgm carburetors come directly with the short conversion screw for models without separate lubrication.
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Buy short adjusting screw here
