A mate gave me one of the newer round air cleaner assemblies so I fitted it to the 13 ultra. I machined some new breather bolts to suit and bought a couple of 1/4 bolts for the bracket and it went on easily. Old system was the oval cover with stage 1 SE filter element.

Certainly looks good!!  job well done.

Perhaps the extra range is a result of it now running a touch lean, more air without increased fuel ...

I thought about it maybe leaning off too but if that was the case combustion temps would have gone up as well, which would have shown up on the digital temp gauge I have on the rear plug. I think the lower intake air temp has a lot to do with it as there is more air mass and hence O2 for combustion. I am not familiar with the HD ecu strategies but I would assume it is closed loop at low to mid throttle so would reduce fuel to maintain mixture with higher intake air temps, which would reduce power. Cold air intake should help a bit but I am a bit stunned at the difference. All I can think of is that maybe the SE element I took off was restrictive as well as getting hot air. If I can be bothered at some point I might measure the difference in intake air temp between the two systems. Might not too as I'm just happy with the entirely unexpected improvements. 20 years ago I would probably have analysed the shit out of it and worked out exactly whats going on but my days left are way less than the days I have lived so maybe I'll just enjoy the ride and keep polishing the new intake.