Stig, is there a chance to get these stumbles on a video and/or sound record during the 20-30 steady cruise rides somehow? Helmetcamera, Go Pro, Mobile/Microphone mounted close to the Engine etc.? So you won´t necessarily need to prove the stumble issue with the mechanic behind you on the scooter. because this might cause other warranty issues due to overload rides. And then they can´t get away with "runs perfectly"...
The Video/Sound File would then also be very interesting for the forums community to see/hear.
