The single shaft Solex 40 PII were first used by Porsche in the 1955 1500cc Carrera
engines installed in the 356.  The 40 PII-4, came with the first Super 90 engines in late

Split Shaft vs Single Shaft

As the name implies, the original Solex 40 PII-4 had one single solid shaft,
in each carburetor holding the two butterflies.  To address stricter emission control
regulations that came into effect during the late 1960's, the split shaft solex was
designed. It has a better transition from idle to main jet operation due mostly to the 2
additional by pass ports in the throat; as well as having a separate idling circuit.
As the name implies, the split shaft consists of two independent shafts, each controlling
a single butterfly,  in each carburetor.  Infinite tune ability was the idea at the time.

Split Shaft Weak Point  

The split shaft Solex’s two independent shafts are controlled by a  central mechanical
device made of pot metal,  which, when working according to design,  synchronized the
butterflies so the airflow is equal in each throat.  When these carbs were new, this
device worked well.  Now, being nearly 50 years old, these devices are broken, worn,
have rusty screws, and the plastic block degrades so ultimately, there is little butterfly
control.  This mechanical device also added to the complexity of the carburetors, making
them difficult to rebuild and maintain, plus requiring  
a certain skill level to tune that many owner/operators
haven’t acquired.

We now do split shaft restorations by special order only.
The cost will be based on an hourly rate due to the
lack of quality available  parts and the complexity of their
set up.

An alternative
Solex Split Shaft Conversion

The gold color you see in
this photo is available
only  by special order,
356 Carburetor Rescue,  285 Morgan Road,  Sedona,  Arizona  86336

Call Jim or Candace at 928 204-0507 for pricing information on our products and services

Call John at 619 224-3566 for technical information or installation help on the carburetors

If you have problems with this website, contact Candace at or call 928 204-0507

Thank you for your interest in our products
We found a way to convert the split shaft to a single shaft
eliminating the mechanical device. In our modified version, the  
shaft is   
made from chrome-moly steel and supported by four bearing
bronze bushings     (originals were brass). Now you can have
all the advantages of the split shaft Solex; extra power and
smoother transition, with the relative ease of adjustment that
single shaft Solex are known for.  In addition to new shafts,
bushings and butterflies,  these conversion carburetors
include 8 newly manufactured accelerator pump parts to
provide reliable smooth carburetors..