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Discussion Starter #1 (Edited)
I've had this problem since I first got my Vulcan 900. It doesn't leak much, just a little, but enough that I had to wipe it with a rag almost every time I rode the bike. Now it no longer leaks. And I understand this bit of oil came from the crankcase breather into the air filter. I corrected this by ordering the 2 o-ring gaskets on either side of the air filter, at my local Kawasaki dealer. The leaking gasket was the one behind the air filter. When you buy a new air filter from the dealer, it comes with the front one.Total cost about $11.00 for both. The old o-ring gaskets fairly quickly get shaped into square cross section instead of round, so watch out for this if you decide to replace them.
 

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I had some oil in the air filter box after doing an oil and filter change, but there never was an external leak. Problem was solved by not filling the engine oil level higher than halfway between the lines on the engine oil level sight glass.
 

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Discussion Starter #3
So, you want your pistons and rings and connecting rod uppers to run dry then? Remember these things are splash oiled. (I know this comment is going to start a debate, and I apologize for that, but I would like to know other people's feeling about this, thanks).
 

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splashed oiled Hmmm...

So, you want your pistons and rings and connecting rod uppers to run dry then? Remember these things are splash oiled. (I know this comment is going to start a debate, and I apologize for that, but I would like to know other people's feeling about this, thanks).
My old John Deer Lawn Tractor was splash oiled - had a Slinger on the crankshaft that would sling the oil around the engine.


My Vulcan 900 has an oil pump that pressurizes the oil system keep bearing lubricated with oil pressure.

pressurized oil systems do not relay on Crankcase Splash - actually an over filled crankcase will cause loss of power and oil cavitation / not good.


What are you talking about??? :nerd::surprise::nerd:
 

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So, you want your pistons and rings and connecting rod uppers to run dry then? Remember these things are splash oiled. (I know this comment is going to start a debate, and I apologize for that, but I would like to know other people's feeling about this, thanks).
Sorry, but that doesn't make sense. The space between the lines on the oil level sight glass define where the oil level should be - anywhere in between the lines is what Kawi intends, and that means that the engine will be properly lubricated even if the oil level is at the lower line.

Don't know what knowledge source your are citing but whatever it is is incorrect.
 

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blow back.
 

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Discussion Starter #7 (Edited)
What are you guys talking about??? The last time I checked, there is no oil passage going thru the connecting rod to the wrist pin (this would weaken the rod, though in theory there could be a small passage, easily clogged). There is no oil passage going to the piston skirts or rings. These things are still splash oiled. Check your service manual. So back to my original question, you WANT these parts of the engine to be properly oiled, right? So if there is a small amount of oil in the crankcase air space, then aren't these parts being properly oiled?
 

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Wow. I have been inside a lot of gas engines over the years, not the Kawi V twin yet, but some things are pretty standard. Certain parts of any engine are splash oiled (inside piston skirts come to mind), but a majority of components are oiled through block passages (yes, even small ones), crank and cam journals, push rods, hydraulic lifters, etc. Splash oiling is great for gear boxes, not so much for engine components unless we are talking lawn mowers. Crank and cam bearings need oil pressure to create the cushion between rotating components, oil flow is needed for cooling and to remove contaminents. Oiling the wrist pin can be done several ways that I know of and one is oil splashed off the crank, the other being forced through due to the oil rings whick I believe the Vulcan uses since they employ 2 compression rings and a set of oil scrapers on each piston. I would say to scan and post some of the info you have been getting from the FSM.
 

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Discussion Starter #9
You are most likely correct about the wrist pin oiling. I did more research and almost all internal combustion engines use some form of splash oiling (or spray oiling) under the pistons. The rare exception appears to be large heavy duty diesels that are stationary or drive big ships.

So here's the issue. Kawasaki designed the air cleaner to catch oil from the crankcase breather. Why would they do this, if they weren't expecting this? There's not a lot of oil there, but what is there seems important to me. Again, it might be convenient to not clean the air filter housing, but I'm not sure it's helpful to run a lower level of oil in the long run, to avoid this.
 

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Every internal combustion engine will have some oil mist that escapes. Cars use a PCV system. Bikes usually route it up and hope it gets mixed with incoming air. Post 5 is spot on, too much oil and it will start getting churned up by the crank. The oil should be between the lines on the sight glass, this is outlined in the owner's manual.
 

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Discussion Starter #12 (Edited)
Gosupes, with all due respect, the owners manual does NOT say that. The owners manual says to not fill the crankcase with oil above the full mark. It's generally ok for the oil level to be between the lines, but the manual does NOT say it SHOULD be there. If you think it does, you are welcome to post the page.

I also think we are splitting hairs here. As long as the oil level is somewhere between the lines, the bike is good. My personal opinion is I like to have the bike full (but not overfull). I shy away from lowering the oil level to avoid oil in the air cleaner. My thinking is if there is less oil in the blow by gases, there is less oil to splash lube the pistons. Yes I read post #5 and I generally agree with it in principle, but I don't entirely agree with it, for the reasons I just stated.

The whole point of this thread, was to convey how easy and inexpensive it is to stop the oil leak from the air filter housing. Lowering the oil level to stop the leak was not what I had in mind.
 

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Just what do you mean here -

"The owners manual says to not fill the crankcase with oil above the full mark. It's generally ok for the oil level to be between the lines, but the manual does NOT say it SHOULD be there."

Either its OK to be within the lines or its not, which is it you're saying?
I'm confused!
 

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Gosupes, with all due respect, the owners manual does NOT say that. The owners manual says to not fill the crankcase with oil above the full mark. It's generally ok for the oil level to be between the lines, but the manual does NOT say it SHOULD be there. If you think it does, you are welcome to post the page.

I also think we are splitting hairs here. As long as the oil level is somewhere between the lines, the bike is good. My personal opinion is I like to have the bike full (but not overfull). I shy away from lowering the oil level to avoid oil in the air cleaner. My thinking is if there is less oil in the blow by gases, there is less oil to splash lube the pistons. Yes I read post #5 and I generally agree with it in principle, but I don't entirely agree with it, for the reasons I just stated.

The whole point of this thread, was to convey how easy and inexpensive it is to stop the oil leak from the air filter housing. Lowering the oil level to stop the leak was not what I had in mind.
This was just a clip from an online manual that had been posted, but if you prefer, I could scan the page out of my owners manual at home. Or you can scan yours and prove otherwise.

Check the engine oil level through the oil level inspection window. With the motorcycle held level, the oil level should come up between the upper and lower level lines next to the oil level inspection window.

Every motorcycle I have ever owned states basically the same thing in regards to sight glasses. Do what makes you happy, it's your bike.

I would agree on not lowering the level of oil due to some slight mist condensing in the air filter if you are in the capacity range, but it can be a symptom of excessive blowby or an overfull condition. If overfilled and you wait long enough, the oil will eventually find it's own level after the excess drips out of the air filter housing. If blowby is the culprit, then it's just borrowed time.
 

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Discussion Starter #16 (Edited)
Here is a screen capture from the owners manual from a 2018 900 classic. Had to get in tight to stay under the image size limit. We my have to agree to disagree on this one.
 

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This is out of hand crazy. It ain't that hard...


The oil level for safe/normal operation is between the low and high marks.

That's why there are usually two marks; in common parlance the "add" mark and the "full" mark. Normal operating level is between the two.

Fill it to the full mark if you wish, in theory that's fine. But, nothing says you have to maintain it exactly at the full mark between changes.

Me, I shoot for as close as I can get to using full containers and ending up between half way and full.
 

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O rings in the air filter

Started with O rings in the air filter stopping the leakage of oil in the air filter. May be a good tip.

But the Vulcan 900 still runs a pressurized oil system.:nerd:
 

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Here is a screen capture from the owners manual from a 2018 900 classic. Had to get in tight to stay under the image size limit. We my have to agree to disagree on this one.
That's the procedure for oil change, the assumption being the level will drop once the filter fills up. If you look about 5 or so pages before that, in the inspection section, it outlines this. But whatever, I'm done beating this horse.


Sent from my SM-T380 using Tapatalk
 

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Discussion Starter #20
Gosupes, glad you noticed that. But pre-filling your oil filter with oil (which is something I do) before you put it on, messes up this procedure.

This whole debate has become silly. One could argue that an illustration showing the oil level half way between the full line and add line, helps to illustrate exactly where those 2 lines are. But in my opinion does not mean that's the ONLY level you should run. But what's the point? Do your thing, I'll do mine, as long as the oil level is SOMEWHERE between the lines, you're good.

If you have an oil leak below the air filter that you have to wipe off with a rag, you can get an o-ring gasket for about $5 and change from the dealer, that will fix the problem. That's where I started this discussion, and that's where I'll end it.
 
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