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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

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.

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?

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.

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

Mucka wrote: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.

I fixed one issue the vacuum pipes where connected slightly wrong

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.