Can you share the plot?
Usually biggest vibrations are at Y axis.

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Spirit System developer

I haven't made a screenshot yet, but if the weather is good I'll test again this weekend and take a screenshot.

I've made progress, the vibrations are down from 250% to 116%
The dampers do not have the same size when compressed, so 1 blade holder is 0.1 mm further from the main axis and causes imbalance.
I'm going to try to solve this by putting shims on the other side.
The vibrations are already halved on the first attempt.

do you know the spindle where they fit the main holder (those who keep the blades)
when tightening the screw on the thrust bearing?
Many times on one side gets pushed more and the other side less, and this difference only audible at very high rpm.
if you changed the main bearings, damper, main shaft and spindle and you still have the problem
you have to check the screw i circled you in green you must have the same distance with the spindle.
it's not easy have the spindle with the same measure.
Unscrew the two screws and look inside the hole of the thrust bearing, you must have the same distance from one side to the other.
you regulate this thing when you tighten the two screws at the beginning

the screw you point to sits against the fethering shaft on both sides. ( the heli is a ALZRC X360, a Gaui X3 clone with belt tail )
I don't have any new dampers yet, but these are on order. All I can do at this point is add more or less shims and check the position of the blade holders relative to the main axis.
but i'm making progress. From 116% to 64%
If i get less then 50% it's ok ?

if you change the spare parts and lower the vibration continue in this mode