Here is an example video of how the jello effect looks like. Every digital sensor is more or less prone to vibrations, which leads to waves within the video. So that is noting special to the K2.
(don't watch the video online, as Dropbox throttle the speed, which leads to decreased quality)
Video starts at about 120 km/h and goes up to 150 km/h (7000 rpm).
If you experience the same, you have to dampen the camera in some way or choose another mounting location. Well...seems that I have to dampen it in some way.