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Re-Routing Crankcase breather hose

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Hello.

Can anyone tell me how to re-route my crank case breather away from my airbox?

I am thinking about doing this and I want to know what the advantages and disadvantages of doing this would be.

I have noticed all the factory teams do this.

Also if anyone has any tips or pictures of how they did it, it would be much appreciated.

Cheers,

Sam.

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Remove hose from airbox and plug fitting with RTV silicone. Let it setup and re-insert hose onto fitting. Remove plug from lower hose.

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What are the advantages? I haven't even thought of this and would have to go look at my bike to know what the heck you guys are talking about, lol.

(I know where the tube is with the plug in it, I just haven't looked closely enough to see how it's associated with the airbox)

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Hello.

Can anyone tell me how to re-route my crank case breather away from my airbox?

I am thinking about doing this and I want to know what the advantages and disadvantages of doing this would be.

I have noticed all the factory teams do this.

Also if anyone has any tips or pictures of how they did it, it would be much appreciated.

Cheers,

Sam.

I filed the air box bung with epoxy and used clear fuel line hose from the valve cover. Ran it to dispence just above the top of the chain. The advantage is you are not pumping hot engine air into the intake tract. This keeps tthe intake tract cooler.

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Tip overs result in oil possibly flowing into airbox. Also, blowby and water don't have to be drained.

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Hello.

Can anyone tell me how to re-route my crank case breather away from my airbox?

I am thinking about doing this and I want to know what the advantages and disadvantages of doing this would be.

I have noticed all the factory teams do this.

Also if anyone has any tips or pictures of how they did it, it would be much appreciated.

Cheers,

Sam.

I wrote this in another thread also so sorry about the duplication but it should be in this thread.

Part of the reason is to prevent oil from being allowed to just leak onto the ground. It goes into the airbox to allow the line to vent off pressure while keeping it plugged on the bottom. Theoretically only vapors go to the airbox while the lower plugged end captures the oil to be drained and disposed of properly. I can attest that running the vent line straight from the head down to the bottom, without a plug or going to the airbox, allows carbureted bikes to run much better. It helps remove a lot of the back firing caused by fluctuations in the air temperature and O2 going into the carb. The air going into the carb is more consisten with your current jetting setup. It will probably still be an improvement on the '09's but not as much since the EFI adjusts for the air temp and O2 constantly.

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so is it kinda more of a epa deal than a functional part of the motor? a friend of mine tiped over his 09 and filled his airbox full of oil,which inturn ran onto the chain and ended up allover the place. if it doesnt hurt the motor to not have it hooked up then im gonna run mine out the buy the linkage and be done with it:thumbsup:

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I don't know if I would do it. These engines are designed to have crankcase pressure. If you use a straight hose from the top vent and plug the airbox hole, you could suck dirt into your engine. I would rather leave it be, and empty the hose once in a while and plug the hose back up.

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I don't know if I would do it. These engines are designed to have crankcase pressure. If you use a straight hose from the top vent and plug the airbox hole, you could suck dirt into your engine. I would rather leave it be, and empty the hose once in a while and plug the hose back up.

You would have to have vaccum to suck anything up the breather tube. Doesnt happen.

The YZFs have this same routing from the valve cover down the frame and vented. never any problems.

Glad someone posted the MDK kit. Pretty slick kit for $35 and you reroute the vent hoses from the carb back behind the swingarm bolt. Makes a much more sano looking motor.

Best benefit to doing a kit or reroute of the hose is not having to deal with it when you pull the subframe on and off.

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After looking at the bike heres how I understand it.

A line comes off the valve cover about 4" and comes into a "y" connection. From that one line continues down to above the chain area and is plugged. The other is routed to the boot between the filter and the throttle body, not the airbox. so theoretically if your bike is upside down long enough, etc., your going to suck straight engine oil directly into the throttle body. My question is this, does this NEED the vacuum from the line which is connected to the boot? I don't think it does but would like some thought son this before I do the mod. Give me your thoughts. I have a way to do this for about 50 cents and it would take about 2 minutes but I'm just wondering about the vacuum.

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There is a big DOWNSIDE to doing this. You will end up with dirt in your engine! For one you will not notice a difference in power. Race teams rebuild their engines so often that they don't worry about a tiny bit of dirt, plus they don't ride in dust. They also replace that vent hose every week as well. It looks trick, but beware. Another good thing about keeping it stock is it allows you to see how much build up you get after each ride. If you get more than an inch or two, you have a problem.$0.02

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There seems to be some confusion here.

The crankcase breather comes out of the case near the kickstarter. I would re-route this up near the top of the shock and zip-tie it somewhere. If you're riding in mud and water I'd definately do it.

The breather that goes to the airbox is a vent line that comes off of the valve cover. I would leave it alone, unless you're getting a lot of blow-by and oil in the airbox. In that case, you've got other issues to deal with. Either you've over filled the engine oil or the top end is worn out, pressurizing the bottom end and pushing oil out of the breather.

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