Vent nipple is open, photo attached tv. Have been running it without a hose since I got tbe bike with no problem.
...Except for the bugs that crawl in and nest, or abrasive dust invasion. Rain or wash water ingress?
And, if you do get excessive piston ring blow by, the engine oil sprays out of there covering the entire rear of the bike. If it weren't a required item, why do you think Honda went to the expense of installing one on every bike they sold? Give them a little credit, please.
Anyway, it's good that you didn't plug it off. We can check crankcase pressure build up off the possible cause list. I was looking for cheap and easy fixes. Now it warrants a more serious investigation.
If you have excessive oil smoke, it is getting past the valve guide seals or the piston rings. (or leaking onto the exhaust system.) Time for a leak down cylinder check, or at least a compression check, to ensure mechanical health of the cylinders.
Do the spark plug deposits show anything interesting? Are they the same for each cylinder position? Did you verify each head pipe runs at about equal temperature? We need to know if all four pots are burning, or if one is just pumping fuel/air without igniting. If the latter, white fuel vapor out the exhaust is a possibility.
Have you checked for spark at each position?
Cheers,
