From what I am reading these bikes run rich over 7000rpm and that the de restricted bikes have the throttle valve/position sensor set around the 80% for wide open throttle. 80% of the bikes red line rpm would be around 6500 - 7000rpm, maybe the ECU goes into a default AFR setting above this rpm - hence they run rich and are difficult to adjust. No science to this just a random thought from reading all the info on the tuning of the bikes
