Solex 4a1 carb secondary butterflys issue

[Mucka]

Hi

I have a slight flat spot on my 320/6 with solex 4a1 carb, I had a look today and the larger secondary butterflys have no resitance and are open all the time,

I found this pic, mine are not closed like that.
What part of the carb controls the secondary butterflys?

Thanks

[Peter V.]

They open by vacuum which comes by opening the big fuelflaps (bottom). They are closed bij the vacuumbox located at the side of the big airflaps. There is a connection between. The axle of the big flaps has a little spring which makes the closing easier.

The flaps must move without any resistance and often that is the problem with the 4A1 carb. Mostly by dirt and greas or a torned carbcover the flaps cannot move easily.

[Mucka]

Thanks Peter,

I had a better look at the carb today and it seems I am missing this return spring, is it replaceable without stripping the carb?

[Peter V.]

Yess, it is but you must tension the spring again i believe. Normal it must be possible to remove the screw where the spring is on.

[Mucka]

cheers, I cant find anything online that will be a suitable replacement, Is it possible to still buy solex spares at all?

[Peter V.]

cheers, I cant find anything online that will be a suitable replacement, Is it possible to still buy solex spares at all?

That is a very difficult point. The best way is to buy a used one and keep that for spare parts. I have about 6 4A1 carb here to use as spare parts for my own and refurbishment of others.

[Mucka]

I fixed one issue the vacuum pipes where connected slightly wrong

[Peter V.]

That is a different schedule then i have. You have the type 2 carb so i believe that you have a ignition with advance and delay vacuumconnection.

Also no vacuumcontroled fuelpressureunit.