My 2007 Classic had the same problems with "mayo" blocking off the crankcase outlet, catch can duckbill, and return line (it has a duckbill in it, too)... system is supposed to provide negative crankcase pressure through the duckbill in the can, vent the gasses over to the airbox, condense the oil and water vapor, and return the glop to the timing case. When the outlet tube from the crankcase or the duckbill in the catch can get plugged up, the slight negative crankcase pressure provided by the duckbill isn't there, and oil vapor gets blown past the rings... the bike starts "using oil" and I usually have "mayo" on the dipstick as well. if the return tube gets blocked (and there's a duckbill in that line, too) the catch can doesn't drain properly, the duckbill gets plugged, and the effect is the same - oil blow-by. Mine plugged up regularly early in the season when it was cold - takes time to get the oil up to temp, and the plumbing acts like a condensation tube... just have to take both tubes and the can off and clean everything out.
I don't like the idea of any of that junk going back into the crankcase, so I split the return tube and left about 2 inches attached to the return port on the timing case, then blocked the tube with a dowel. Left about 4 inches attached to the catch can, and blocked that with a dowel, too. Now I can drain some of the stuff(mostly water) in the catch can by removing the dowel plug in the line. Catch can still gets glopped up eventually, so I pull it off and clean the can and the duckbill inside every 500 miles or so.
Mike and Stumpy in Michigan