But I believe it IS broken. With stock jetting my 912UL with KN-filter pods run so lean at cruise that I fear burned valves and gearbox damage from the vibration I can feel. Only at cruise
I am trying to richen it up at cruise is all. I have heard others with same set-up (912 UL and no airbox) say 'thats the way they run' but I think there is a lean-condition caused by the removal of Rotax airbox. Without an AFR meter I would be less aware
Google is full of posts by motorcycle owners struggling with CV carbs running too lean after removing factory airbox. The stock carb set up recommended by Rotax was made for airbox applications I believe
But you are right; some of us have a tendency to obsess. Having an AFR meter makes it hard not too when the needle is at 15.5