Lean idle keihin

Hi guys.

I got my berg up and running with new liner, piston and valves.
Now I have an issue with lean idle, where I have to set the idle screw to almost maximum when warm to run without choke, with choke the rpm rises drastically and I have to back off the idle screw multiple turns to have it idle at good rpm with choke.

I tried couple of different idle jets #42-50, cleaned the passage behind pilot jet and mixture screw a couple of times (there was some black rubber).
At one time it did idle fine without having the idle screw nearly fully turned in. But then the rpm fluctuated weirdly at idle.
Also the fuel filter in the carb is clean.

Also my rpm rises if I lift the rear on heavy braking. Could the float height be my problem?

The slide plate is ok expect for a few surface scratches The o-ring also pushes the plate outward, but I just realized I put it upside down. Somehow I thought it should be with the peak pointing downward and the hole near the center on the upper side of it.