My brushless MCPx thinks it's a dolphin!

[jamesandyori]

Really!

Ok here is the skinny. Recently my MCPx has developed a porpoising action. It's a slight up and down movement at the nose. It's not constant and will calm down in a hover.

Here is my heli's breakdown!

MH 3 bearing CF frame
extended solid boom with cat 5 wire soldered directly to the board from a 120 motor
plantraco turbo prop
brushless system with a HP05 s motor and 7m speed control
MH swash
Rakon boom support
MH hub
fresh clean servos
new main gear
new MH solid shaft
V-1 board
I use Hyperion 550 mAh batteries with stock plug installed.

I use the stock plug on this heli. The deans seems too bulky for me.

What I've done is:
Replace the feathering shaft, main shaft, main gear, cleaned servos.

So here we are, with my very own flying dolphin.

Any ideas? Could the stock plug be causing the problem? Is it allowing enough energy through to the system?

thanks,
James