If oil continuously blows out the crankcase vent tube (more than a drop now & then) it could mean either the oil tank is overfilled or the breather gear's timing mark is misaligned with the cam gear's mark.
If the crankcase only spews oil when the bike is started after sitting unused for a few days, then it means oil is seeping from the tank into the crankcase due to the check valve in the oil pump either having a speck of dirt holding it partially open or having a damaged ball and/or seat.
blocked pcv or excessive piston blowby..
intake manifold leak
Take it to an experinced mechanic and do not pass go!
Sounds like something in the ventilation system is plugged causing negative pressure. Engines that are worn, have not had oil changes on schedule or have been running "lean" can have some serious problems. If rings wear or if the ring groove is fouled with tar (burned oil) the rings may not be able to provide an adequate seal against the cylinder walls. If the exhaust gas can leak past the piston rings there will be a buildup of exhaust gas pressure inside the crankcase. The condition is called "blowby". The PCV valve assembly cannot possibly keep up with the exhaust gas that leaks past the piston if you have blowby. Unfortunately, severe blowby can push against the crankshaft seals causing the engine to leak oil.
Maybe but more likely its the other way around. Oil blowby will ruin the converter quickly. Perhaps if the check engine light was on & the engine quickly replaced then the converter would still be good. A clogged cat will just rob performance & the engine might not start. The oxygen sensors abre probably ruined from the oil blowby too.
blowby caused either by worn or broken piston rings and or valves May want to check for missing dipstick, oil filler cap etc.
ventilation is the degree of something
Someone whom would sit in a confined area and open and close the door when a cart of coal came, this would cause ventilation in the mines.
This is called blow by. Caused by a defective crankcase ventilation system or worn rings.
harley Meyer is awsomely awsome
The answer is subjective. My pick would be the Road King
Downdraft ventilation would be the smart option for an indoor grill.