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Discussion Starter #1
Maybe I missed it along the way but I don't think anyone ever mentioned the true cause of the Teryx and Brute blowing oil in the airbox.

I might be reporting old news so forgive my ignorance if everyone but me knows this.

There is a rubber tube going from a cavity in the middle of the case down into the bottom of the motor and it sits down in the oil. Air in the engine from blow by and from air coming in as the piston moves up down is forced thru the oil into this tube then out the tube going to air box. The purpose of this is to control the amount of engine vapors being released into the atmosphere, the oil traps them.

So basically the air is being forced out of the engine but thru the oil. Kinda like blowing air thru a straw into a glass of milk but in reverse.

So when we do the next engine build we are going to remove the rubber tube inside the crankcase and we believe this will totally stop oil from being pushed into the air box.

We are working on a cost effective solution to the oil issue for everyone not going in their engine. We did the prototype on the present engine build.

Todd
 

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Maybe I missed it along the way but I don't think anyone ever mentioned the true cause of the Teryx and Brute blowing oil in the airbox.

I might be reporting old news so forgive my ignorance if everyone but me knows this.

There is a rubber tube going from a cavity in the middle of the case down into the bottom of the motor and it sits down in the oil. Air in the engine from blow by and from air coming in as the piston moves up down is forced thru the oil into this tube then out the tube going to air box. The purpose of this is to control the amount of engine vapors being released into the atmosphere, the oil traps them.

So basically the air is being forced out of the engine but thru the oil. Kinda like blowing air thru a straw into a glass of milk but in reverse.

So when we do the next engine build we are going to remove the rubber tube inside the crankcase and we believe this will totally stop oil from being pushed into the air box.

We are working on a cost effective solution to the oil issue for everyone not going in their engine. We did the prototype on the present engine build.

Todd

True its in the oil but it doesn't actually vent from the oil... It vents from the hole going to the side cover. On the 08 brutes and the teryx's they've enlarged the hole as well as added a bigger tube right there. I've never quite understood why that tube runs down to the oil because then it makes it easy to act as a siphon under high pressure. I've rebuilt countless kawasaki v-twins and done many performance motors but I'm not a engine designer so I've left it alone as they wouldn't go through the trouble of making these things bigger if they could just simply remove the tube and it would fix the problem imo.

Maybe Mickey can chime in on this.
 

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Discussion Starter #3
I know it vents from side cover but look at the passage next time your in one.

The hose goes into the internal passage then one side of the passage goes to the left and the other to the right of the engine. The air in the engine gets pushed thru the oil and it is to stop the vapors.

Thinking outside the box on removing the tube.
 

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This is good stuff guys...not that I would take apart my engine to eliminate the problem? BUT it is nice to know for us amateurs so if we ever have to tear down our motors we would be able to address the issue...

Nice job Todd...keep us posted...
 

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Todd, I am not sure of the Kawi design at all but are you thinking of removing and/or blocking it off? I am sure you are aware of the need that the crank case has to vent otherwise now you are pressurizing it and then you blow seals. I am not a small engine mechanic and don't have any experience with it but I am an automotive mechanic and cars/trucks need to breathe. I live in cold weather Canada and when the PCV (Positive Crankcase Ventilation) system freezes up in winter, we get lots of customer in because engine oil has been blown out the dipstick tube because it is the easy way to vent, the odd time I have seen it blow out front or rear main seals.
Getting a little long winded now, just wondering if this is what you are thinking about or maybe you have an idea for a cure. Let us know! :wave:
 

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oil in airbox

Harley Davidson had the same problem with oil in the air filter when mods were made... the fix for them was (is) to put smaller vent tubes going to the back side of the air filter plate. Original vent tube is like 3/8" and the "upgrade" is an 1/8" tube. The other trick is to run 1/2 quart low on oil...
 

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Harley Davidson had the same problem with oil in the air filter when mods were made... the fix for them was (is) to put smaller vent tubes going to the back side of the air filter plate. Original vent tube is like 3/8" and the "upgrade" is an 1/8" tube. The other trick is to run 1/2 quart low on oil...
I thought if a Harley didn't leak oil somewhere, then it wasn't really a Harley!!!
 

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I will tell you for a fact that if you close the vent tube that is supposed to vent the crankcase, you will blow out the main rear output shaft seal......and it makes a big freaking mess!!!

I have a friend that it happened to, yeah thats it.
 

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If you are inside the engine..Why not cut the tube off close to case??? It will be out of the liquid, but still vent into breather???
 

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Guys, Ive got a train of thought in this issue.....


If the hose were to be out of the oil......would that cause a pulsating vacuum in the plenum from the piston forcing air in and out of the engine ? Perhaps the extra pulsations timed with the induction of the air/fuel mix, KAWI engineers say a problem with that ? A nice siphon brake, or a catch can with a drain back into the engine with a small one way fitting (check valve) would seem to fit the bill to (filtered air for the brake of course)

One more thought.....if you wanted to dampen the vacuum impact, would it be better to have the bottom of the breather tube in oil ?

Is the tube (in factory form) submerged in oil in the bottom of the case ?



Edit: In retrospect......

If it was necissary, would are our car engines open vented to the air cleaner. Id delete what I wrote above.... but I guess im lazy.
 

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Discussion Starter #14
The catch can is or siphon break alone is not enough, we have a fix but only had prototype on this particular vehicle.

The issue with tube is something you can only do if you split case.

I have set my mind to fix this and do it without breaking the bank.
 

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i had a 02 1800 vtx. it would throw a small amount of oil into the breather when to many front wheel come ups or alot of racing.when i changed the breather to a thunder air i changed the crankcase set. i bought a crankcase breather and mounted it out of the air intake.solved my problems and didn't smoke anymore from oil in air filter either. would this not be a solve?
just wondering
Crab
 

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There is no fix to keep the oil from blowing out. Cutting or removing the tube will not fix the problem,in fact most of the time it blows more oil out.For those doubters you can cut the tube off by going in when you have the cylinders off and cut it off.

Kawasaki has tried 3 times to fix this by going 3 bigger size tubes. 4 times if you count the 09 Teryx with Kawasaki's version of my YFZ mod. Todate this has been the only mod that works perfect by returning the oil in the best place. Notice I didn't say it fixes the problem,but it is a mod that works.
 

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oil in airbox pt.2

Ok... I know Kawi has many lab rats (in white coats) looking at this, but as my previous post says, the vent tubes on my Harley are smaller. GMC had a recall/update on the '02 era 5.3l where the engine was blowing blue smoke (never mind the FORD/DODGE cracks) and the fix was that they came out with a PCV that has an 1/8" hole vs. the stock 3/8" or 1/2" hole... My belief is that the free(er) flowing air filters, exhaust, higher HP and higher RPM's is actually pulling oil into the airbox, not pushing it in from the crankcase. Todd's tests show there is not alot of vacuum in the air box, so perhaps it is a venturi effect. Look at the airbox/vent tube layout... classic venturi. My Harley and my GMC never had issues until I made mods. that included some or all of the things listed. The smaller vent tubes and the PCV eliminated the issues.:D
 

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Ok... I know Kawi has many lab rats (in white coats) looking at this, but as my previous post says, the vent tubes on my Harley are smaller. GMC had a recall/update on the '02 era 5.3l where the engine was blowing blue smoke (never mind the FORD/DODGE cracks) and the fix was that they came out with a PCV that has an 1/8" hole vs. the stock 3/8" or 1/2" hole... My belief is that the free(er) flowing air filters, exhaust, higher HP and higher RPM's is actually pulling oil into the airbox, not pushing it in from the crankcase. Todd's tests show there is not alot of vacuum in the air box, so perhaps it is a venturi effect. Look at the airbox/vent tube layout... classic venturi. My Harley and my GMC never had issues until I made mods. that included some or all of the things listed. The smaller vent tubes and the PCV eliminated the issues.:D
It has nothing to do with the air box.You can take the hose off the air box and it will do the same thing.
 
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