Lately I've noticed a bit of rough running in the mid-range rpm band on my 912UL (Throttled back to 3500-4500 rpm). It has been most noticeable during the cold of the winter.

Reciently I synced the carbs so I know that was not the issue. In talking to one of my friends who is a Rotax guy, he concurred with my assessment that it was running lean.

To fix this mid range issue, we adjusted the needle position from the second (from the top) position to the third. I was amazed at how smooth the engine now runs in comparison.

I just thought I'd pass this on.