Yaw problem after changing props

[d12bn]

I had everything working ok until I changed from 1045 to 1038 props on my DJI F550 with Zenmuse Gopro Black. Now I have this side to side yaw movement. Never had this before. I've adjusted yaw gain from 110 to 200 and still have the movement as you can see in the video below. It was very windy and gusty today.
Any suggestion?
Thanks




YouTube

 

[Peri Jacopo]

I just finished my hexacopter frame. On the first testflight a GWS prop broke due to the high torque of the motors so I switched to Graupner mini rc helicopter.After attaching the landing gear today I did a second testflight to try out particularly the Attitude Mode. Then I experienced some strange effects finally causing a flip which then led to a crash.