# Alternate catch can mod brute force



## Alex_kopriva (Aug 26, 2014)

I know about the catch can mod of the yfz 450 to get the oil out of the air box from Ridin wheelies or going up real steep inclines on the brute but could you just put a one way valve on the vent line to keep the oil from running into air box instead of cast he can so the crankcase can still vent but not let oil pass into the air box? Thanks for any replies


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## NMKawierider (Apr 11, 2009)

Even for a moment if the crankcase pressure gets close to 8-10 ounces the seals would flip backwards /push out. Really all you need is a breather line high on the engine so it could not build any pressure on the surface of the oil when the lower one is covered to push oil up the tube to start with. All you need (and we found this out years later) is to either port a vent in one of the valve covers and "T" that line in to the crankcase vent or even better, get one of VFJ's cam plug vents and do the same. No need for a catch can and far better crankcase breathing. Cake.


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## narock (Mar 12, 2012)

So I am completely confused with this whole catch can thing. I have one of those VFJ port things on its way. So I can forget the whole catch can mod and simply run a line off of this port thing up under pod and put a small air filter on it? Or am I completely confused? And yes, I have read the catch can mod instructions. Think they only confused me more. In the middle of snorkels and rerouting all kind of breather tubes at the moment.


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## NMKawierider (Apr 11, 2009)

narock said:


> So I am completely confused with this whole catch can thing. I have one of those VFJ port things on its way. So I can forget the whole catch can mod and simply run a line off of this port thing up under pod and put a small air filter on it? Or am I completely confused? And yes, I have read the catch can mod instructions. Think they only confused me more. In the middle of snorkels and rerouting all kind of breather tubes at the moment.


With one of those all you really need to do is "T" it into the existing crankcase vent that runs to the air box. No other mod is necessary. Had we known or had this back in the day, we would have never fooled with catchcans.

Think of it this way. The engine is completely sealed except for the one crankcase vent low that can be covered with oil during wheelies. During this time, pressure from ring-by-pass will build and push oil up the vent tube to the airbox. But with another vent up high, pressure can't build and do that.


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## narock (Mar 12, 2012)

Got it. Thank you so much! Any ideas on where to place my T and what size hose it is? Billet breather is 1/2 I think. Is stock breather hose 1/2 as well?

Sent from my SM-G900V using Tapatalk


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## NMKawierider (Apr 11, 2009)

narock said:


> Got it. Thank you so much! Any ideas on where to place my T and what size hose it is? Billet breather is 1/2 I think. Is stock breather hose 1/2 as well?
> 
> Sent from my SM-G900V using Tapatalk


Yeah it's probably about that size. I ran some I think 1/2" from my catch can around to tie back into the airbox and it fit fine.
"T" it in just before the airbox.


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