Have the 912ULS and been flying it for 3 years and love the airplane. Engine runs good but at idle I do have roughness on right carb that is noticeable. Above the 3200RPM level it is quite smooth. Just balanced using the CarbMate device and it's right on the money. Any thoughts on where to start on the right carb vibration. it's been doing this ever since new so I have thought it may be a Rotax moment. JeffB