Hello. Anyone know why on my Brute Force 750 oil comes out of the air box tube. At first I thought the filter was oiled to much and it just was draining out the bottom, but I took it off and the bottom is full of oil but it's not the filter oil, it's engine oil. Too much compression sucking it up into there or what? It's a lot by the way after about 3 or 4 min being stopped I have a 10" circle of oil on the garage floor, that came right out of the tube that goes to the bottom of the air box.
Thanks for any help.

 

Here is what I have found so far... the added 840 kit did it I think.

I have been doing lots of web searching on this subject and for the most part I have found the same answers. Ie "Thats a common problem, when running hard the crankcase creates pressure and pushes oil out that breather hose into the air box, pretty stupid design there is a fix its called a siphon break its a little tank the oil goes into instead of the air box most places that deal with rhinos should have it or know where to get it I got mine at kms performance."
Guys that have put more power like a 840 kit seem to have the prob. A lot. Two things they do… 1. Cut the tube in the middle and attach another long tube that goes up around the handle bar area and back to the original tube. This gives more room for the added pressure to push oil out under hard acceleration and drain back before it gets to the air box. 2. Add this tank that is mentioned above. This will also keep water from draining back into the engine if water gets into the air box then runs down the breather hole.

 

Yes, you found the correct cause and solution!

The "long tube" you are referring to is aka "catch tank" that is supposed to hold the oil which drain backs down to the crankcase when the pressure goes down (or when you slow down!). It is commonly used on engines that run at high rpm for a prolonged time such as on race cars. Even some factory stock cars have such as WRX STI.