Yamaha RJ05 / No power from 8500 rpm (stutters, jerks)

Hello community, I have the following problem on my R6 RJ05: From a fairly exact 8500 rpm the performance is missing. I always describe it like a kind of child safety system The performance is completely gone, the machine starts to stutter and first does not take any gas until the rotary blade falls off again and attracts it again. But only up to 8500 rpm. I had given a system cleaner in the tank last year and the problem was gone during a longer tour, after the winter this year again the same problem. The problem has been the machine for a long time, since I anyway rarely and little driving I had never had to deal with the muse. The good piece should be given for a new MT07 in payment, however the dealer could give me on the basis only “a few hundred” , which is why it is now active also there for the examination there is what it could be. Actuel the workshop is probably in contact with Yamaha whether the error is known. The factory At present, however, it tends to the petrol pump, which probably doesn’t deliver enough from XY U/min. A new pump probably costs ~600€ if I have seen this right with my research. Evtl has some similar experiences or solutions here.