KF2 Tail vibration durning ground engine run

[psjoe]

Hi-
I received a video from the seller of a KF2 showing engine start and run on the ground. Engine is HKS. After engine start and run up the tail starts to vibrate (looks like videos I have seen of in flight flutter). I assume it is a prop balance issue? How much of a concern is this, and what is the possible cause.
Thanks -Joe

[PapuaPilot]

If the vibration is like you described I would be very concerned. The causes would be the prop or engine being out of balance, neither which is good.

[avidflyer]

I would wonder what the rpm was when the vibration was going on. a 2 cylinder engine running real slow wont be real smooth maybe. Especially if the carbs aren't synced as close as they should be. HKS engines are supposed to be very dependable. Mine ran real smooth the few times I've ran it. Although the idle could have been a bit smoother. JImChuk

[psjoe]

Thanks Guys. The KF sold to someone else.