After reading another thread about this problem on this forum, I tried to find the bird comb to modify the airflow around the fork. None of the local stores had it in stock though.

However I wanted a Bagster tank cover and tank bag for my bike anyways, so I bought a Bagster Cross`r tankbag and a tank cover. That took care of the buffeting. 120km/h is no problem. It also gives me room to store some essentials when going on daytrips.

I am 1.93m so I have also invested in a higher Kappa windscreen - thats the same as the Givi screen. I still get some turbulent air coming off the top of the screen, and possibly off the sides. I am considering trying a Kappa Airstream on it to see if that can improve it, but before that I am going to take the windscreen off all together. The reason for that is that if I stand up, my helmet comes out of the turbulent air which reduces the noise considerably. The solution for me might in fact be a smaller screen.

As other people has mentioned, some turbulence comes fromt he general design of the bike with the very high front. The most silent ride I have had so far in motorway speed was on a FZ1N...