I have a 2011 FLTRUSE with 18,000mi. I have the cat removed and a SERT. I change the oil religiously and ride mostly 2 up on various roads on or around the speed limit. I just recently have had engine oil showing up at the bottom of my airfilter. It is not running out but has enough to make a few drops that blow onto the side cover and right side of bike. Any Ideas?
First, make sure the oil level is not even a tiny bit too high. For many of us, running the oil a pint below full solved the carryover problem. However, if you are running the oil level the same as you have for the first 18k miles, and you didn't have a problem during all that time, then you might need to dig deeper.
Remove the air filter element and see just how much oil is actually collecting in the filter and backing plate. It may be that the small amount of carryover that's pretty much normal has just built up over a long time and finally saturated the bottom of the filter element. Clean everything thoroughly, including the filter element, and then ride for a few thousand miles and inspect again.
Jerry