Do higuer nitro can cause vibrations???

[Turbo Boss]

Guys, I have a GPH 50SE with a Webra 52AAR/Weston one piece pipe.
I am using 10% Nitro. This combination has tons of power but since day one I have a tail vibration. When I asembly this heli a use the dial indicator in the fan/flywheel and its was perfect but the tips of the Vertical fins vibrate from one side to other very fast.
I have just fly the heli one time for around less than a tank (10 minutes hover) and land it because the vibration. I try to lean the engine and the problem was worts.
So again I take out the engine to check the flywheel on the dial indicator and its OK.
I have around 10 year flying/assembling helis and this one has intrigue me :( because I take all the time to assembly this baby and I have this vibrations.
The heli is brand new.
My question is if it possible because I am using 10%nitro the engine is producing this problem? Have any has experience a similar problem like this?

THX

[Tom Fiddler]

I would look at the balance of the rotating parts
They may be running true but still be out of balance

[Alfred]

I just know Webra's from Germany when we used them in Aeroplanes.
It then was laway designed for 0% Nitro and we never used more them 5% just to improve the idling if needed.

I would try a headshim if you can get one and see fi this doesn't reduce or cure your problem.