HDX V3 tail vibrations

[Takis]

Hi.
I have 2 HDX V3 and assembled one of them.
I have a terrible vibration that I can't take out.
I am experienced, having 10 helis from Gaui 200 to Maxir and T-Rex, HDX 450(3 of them) and HDX 500.
Everything is balanced and fine.
I think that is the tail, since only when I put the blades the problem is shown. Also I think that the tail shaft is thin.
I need your suggestions for what to substitute or if this is common, what to do.
Thanks for your help.
Takis

[must289pwr]

The only things there to cause that would be the blades them selves or a bent shaft. You could also try replacing the bearings but I dont think they would cause a vibration.
I am currently waiting on some tail shafts because I bent the hell out of my last one when I went in tail first. I am also going to try some of the K & B blades. Waiting on the parts is killing me though.

[nickolai]

i assume this is a hdx300, i upgraded to a trex450 tail shaft/pulley. all i had to do was open up the bearing bores in the tail case halves to let the 450 bearings fit. since i have had no vibration problems with the tail, its all been in the head.