XKE Carburetors 4.2 SU suction chamber and pistons not functioning properly

I just bought a set of Carbs for a 4.2 XKE. Upon inspection I see that the pistons in all three carbs do not fall properly. They go slower than they should and one does not even go down all the way. I do not even have the lower jet installed - so it has nothing to do with the needle and jet alignment.

I understand that each carbs has the suction assembly and piston machined to make a matching pair. I have tried to swap them around and still get the same results.

Can I try to use sand paper to hone them out a little or what? I have added a youtube video demonstrating the action.

Thank you

How do the pistons work in your hands?
First there should oil in the dampers, looks like at least in the last one there is no oil in the damper.
Or try them first without needle’s to be sure the needle’s are not the issue.
If ok, only the needles should be adjusted (centered )
You could also try to move the damper pots around.
I only have 2 carbs, and the dampers can’t be switched, they will get stuck.

Peter Jan

They bottom jets are not installed so the needles do not rub against anything. I do not have oil in the dampers. I will try to add it and see what happens.

There are a few excellent videos on YouTube that show how to perform a ‘drop test’ . Try that first

The first piston drop looks about correct, if there was oil in the damper, the second and third have problems, having said that the third may be better with oil.