09-12 crank case breather

[Darvo]

Can someone explain to me why the crank case breather hoses are routed the way that they are?

I'm talking about the hose from the valve cover, that tees off to a hose from the air box, and then runs down and rests on top of the cases and is plugged.

So my question is, does the hose from the air box need to be connected to the hose from the valve cover?, and does it or they need to be plugged?

I'm running my bike in harsh conditions, and seem to be getting blow by into my airbox, which has me concerned that I might get moisture into the valve cover. So I've been wondering if I can separate the hoses, or leave them un-plugged.

[Darvo]

My build thread may help explain the riding conditions.

https://www.thumpertalk.com/forum/showthread.php?t=1023336

[Shawn_Mc]

The T in the breather line is to allow larger amounts of moisture and oil blow by to run down in to that tube so it doesnt get pumped into the air box. The route the line to the air box for filtered air.

The plug should be pulled from the line from time to time to drain off the excess oil and water that will get trapped in there. The water comes from condensation. You could block the air box inlet and then route the breather line to somewhere more protected and it would fill the intake with anything but then you risk the tube drawing something else in from outside. Somebody makes a kit to put a little K&N style filter on the breather tube for like 20 bucks.

[Darvo]

Thanks Shawn.

Is the plug necessary, our just a safety feature?

.

I'm thinking that the tube may have filled almost completely up throughout the day and that is what caused the oil to get into my air box. I have some coarse foam in the sure box to avoid snow accumulation, it is now saturated with oil, and dripping on my garage floor.

I'm begining to think that I could re-route the airbox line to a safer spot, and wrap a k&n type filter with a pre-filter... Maybe this would help, but I would like to run it without the plug, our maybe extend the plugged hose to allow for more volume in the system??? Any thoughts?

[gyd]

We remove the vent system and plug the hole in the airbox. We then run a vent hose from the valve cover down through the linkage/rear cases. Tokyo Mods makes a kit for doing this but all you need is the black permanent type silicone, and some vent line from Home Depot or auto parts store. After pluging hole in air box with the silicone we put one of those vacume hose caps over the fitting and zip tye it for extra security.

This would not be legal if racing any AMA/NMA stock classes.

[Darvo]

We remove the vent system and plug the hole in the airbox. We then run a vent hose from the valve cover down through the linkage/rear cases. Tokyo Mods makes a kit for doing this but all you need is the black permanent type silicone, and some vent line from Home Depot or auto parts store. After pluging hole in air box with the silicone we put one of those vacume hose caps over the fitting and zip tye it for extra security.

This would not be legal if racing any AMA/NMA stock classes.

Thanks, I think I will go this route, do you plug the hose from the valve cover, or just let it be?

[thecount]

does this do anything for performance or whats the purpose of thdoing this

[bomax]

I mototassinari airbox on my 11 250,they dont even have the hole for the vent and you re route it,so you just run the clear tube from the valve cover,you leave it wide open at the bottom,if you plug it you will cause a seal or gasket to go from the buildup of pressure,it has to breath.

its not the best pic but you can see what i did,i just added some fuel tank foam in there.works great.

[lourencom]

check out Applied Racing website, I believe they have a good solution for your crank case breather hose.

Ciao,

-mike

[Darvo]

does this do anything for performance or whats the purpose of thdoing this

I'm getting quite a bit of oil in my airbox with the stock setup, which means some of it is going back through the throttle body. It's annoying having the oil drip from the airbox, a performance gain would be a bonus, but I'm not expecting anything.

My setup and riding conditions aren't exactly normal, and I'm pretty sure thats why it's becoming a problem for me.

[thecount]

with oil in the airbox i would assume you may have a ring issue pressurizing the base to much pushing the oil into airbox.or maybe theirrs to much oil in the motor side.