The vapor that is vented to the atmosphere does not "grease up our highways"; it's a vapor. Both my bikes are externally vented and never leave a drop on the garage floor. Take a look at the attached photos and tell me again that there is nothing wrong with internal venting.

 

I was cleaning my SE air filter every 3,000 miles. (That's when I noticed oil dripping on my cam cover) Now I am going almost double the miles since the cam swap and going to the S&S air filter. Not sure why but I can only imagine how bad the tops of my pistons are with 75,000 miles on the engine. I have a bore scope but simply have been to lazy to pull the plugs and take a look.

 

Take a look and post your findings, please. Inquiring minds want to know!

 

I would love to hear how 'burning blowby' can be "helpful".

I'd also love to hear about anyone "getting caught" with an external venting system. Please. Motorcycle "inspection" focuses on turn signals; horn; reflective tape on the helmet; and sometimes exhaust noise - when an inspection requirement exists at all.

"Lazy flow"??? Not sure where you came up with this... Your description of the flow path is semi correct, but not your attempt at fluid dynamics. What causes the oil droplets to fall out of suspension is not the pressure drop you describe. It is the "Scotch Brite" media in the first chamber of the breather. This creates a "torturous path" as described in fluid dynamics. Instead of moving along smoothly, carrying the oil droplets with it, the moving air becomes turbulent and essentially "shakes" the oil droplets from it. In a properly functioning system - meaning an engine that does not create excessive blowby, which overwhelms this breather system; and a properly sealed venting system, which doesn't draw oil into itself through internal leaks - this system works pretty well and only vapor - air and extremely small oil particles, too small to collide with the fibers of the Scotch Brite pad and too light weight to be "shaken" from the vented air - reenters the engine.

Also, there is no "orifice". The negative pressure that exixts is created by manifold vacuum. This, of course pretty much goes away at WOT - not entirely, but is drastically reduced.

Internal venting is an Environmental Persecution Agency - oh, excuse me, I mean "Protection" - thing and nothing else.

 

well all i have to say is talk to epa!!! why do you think that engine mfg's are required to vent c/c vapor to a safe location. please, go to a cali inspector and point out your oil dropping system to them, i do not think you will pass.
what you are talking about is a labyrinth chamber or mist extractor. i believe hd either got away or does not use them as i haven't seen any and i just changed my umbrella seals a few months back.
i am well aware of mist extractors, i worked on industrial compressors for 45yrs. are these 100% effective, hardly, seen them clog, seen them blown out and other things.
you need to re-look the flow dynamics, i will throw this out: what happens with a carb when you dump it???? this is only one thing or how about the wind???
the content of the vapor is over 90% water. if you are chucking that much oil, you have other issues!!!
i ran water injection on my 440, aircraft ran water injection including turbine engines, this can significantly increase power.
one other thing: how does an air conditioning system work, if it is like you say, you have no cooling what-so-ever.
one other thing, look at how a coalescer really works. the shaking like elvis is not how it works.

 

They do mist.. Especially if you run hard.. That mist does settle out on the road and can collect on the swing arm or bottom of the muffler. You simply don't see them drip..

 

HD motors do mist when run hard.. It's not enough to be an issue.. Stock motors have the best chance of not misting but build the motor up, make more power and the system can mist significantly. Better to run it into a decent sized catch.. Something large enough where the mist slow down and the oil particulate falls out..

C is not quite right.. It's the drop in velocity that allows the particulate fallout. The drop in pressure will tend to evaporate the oil as it does have some volatility (tho it's low). If you keep the velocity high anything that falls out is picked back up..

 

I'd like to add something to my earlier statement.

I am finding much less oil now that I have changed the air filter, cams and switched oils.

I was running Harley Syn3. Now I am using Redline for the past 15K.

Could this be the reason I am going twice as long before cleaning the filter?

 

Vapor = mist; tomato, tomahto; never said they don't mist and I am sure some mist more than others. I do run both bikes hard but never seen any mist settling on the swing arm or muffler. I do get a light coat of exhaust "dust" settling on the back of the saddlebags after a 300 or so mile run. My main point to buster has been that it's not enough to be an issue for anyone but the EPA. I wonder if the pipes buster runs are EPA compliant of if he is selectively EPA compliant?

Buster can do what he wants but I think I will keep my external venting setup. I vent through crank vents which vent to one of those Dougherty canisters that are full of the same media HD uses in head breathers; the canisters are vented to the atmosphere. When I see a film start to develop around the canister vents, I pull the canister and clean the media; there is never any "oil" to drain out of the canister. The system seems to be effective. I suppose if I were to never clean the media, I would see evidence somewhere on the right side of the bike but that has never happened.