What could possibly be better than the marke....er, engineering genius of K&N, you ask? This. The open gullet. Harleys eat leaves and twigs and schit out mulch.
This was parked on my street the other day and yes, someone moved out and left their old mattress on the sidewalk.
Hilarious, still. Especially the sticker on the bike:
Ass, ass or ass. Nobody rides for free." 
