How-To: Crank Case Breather Mod (with pics)

[snrusnak]

Mechanical Engineers build weapons, Civil Engineers build targets

Never heard that before lol that's pretty funny.

Firefighter, I think you are assuming the piston makes an airtight seal with the block, but it doesn't. There are gaps in the rings and I would bet that's where the air is introduced, like he said ^.

I also think this is being much over thought lol.

Basically, the valves on the engine are one way pressure release valves. Releasing them to the atmosphere, without a filter, should not allow air back in.

 

[firefighter1c57]

yea, there's a third one that goes with that. Chemical engineers wash their hands BEFORE they go to the bathroom.

I probably am overthinking it. F it, I'm just going to go ride the piss out of it. BBFN

 

[snrusnak]

^That's the spirit [up]

 

[zaxrex]

There's much more that I need to worry about than the PCV valves Like why my bike runs so damn lean.

 

[PonyXB12]

Previous owner installed American Sportbike catch can and filter on my 2009 xb12r. Anyone else have issues with oil blowing out of filter during long wheelies? Catch can is empty and oil level is correct.

 

[kbfnail]

Just did this mod. Seems too idle better.

 

[PonyXB12]

Is anyone concerned about taking two hoses that used to be exhausting seperatley and connecting them together, possibly creating more oil to build up in the catchcan (exhaust out the hoses) than normally would? My can fills up pretty much every time I ride, and sometimes spills out the filter. Granted I do long wheelies pretty much every time I ride.

 

[snrusnak]

^I'm not sure what your concern is Pony, the same amount of oil vapor will still pass through the one tube instead of the two. If your concern was about this creating a restriction, it does not.

 

[PonyXB12]

I was just thinking taking that hooking them together, while one is exhausting it may be pulling from the other hose, creating a vaccum and "sucking" more oil/gases/fumes whatever, because it was set up as two seperate lines originally not connected. Unless the other side is "closed" somehow while one side is open? or is it just an open hole in the top of the head?

 

[snrusnak]

They are like one way valves. They can only flow out, not in.

I see what you are saying. Technically I guess you may be correct that since two hoses are joining to one, once they merge the velocity will increase and it will "suck" more out. Just like a y pipe on an exhaust.

Really though, you won't notice anything different. There is only so much pressure in the engine crankcase, and you can't suck out more than is there.

I think we are over thinking this again lol.

 

[PonyXB12]

Thank you sir, I didnt know it was a one way valve, and yes I am def overthinking it but for some reason the ASB catch can set up on mine is filling the fuggin filter with oil when I do long wheelies. I think it may be beacsue the oil level (which is in the middle of the hash marks on dipstick)is a lil too high for this set up during wheelies. I think Eric Buell saying this mod causes issues may be BS. I dont see any benefit from dumping this crap back into the intake.

 

[snrusnak]

Well I would guess that your filter is getting oil soaked just because of the wheelies. Keep in mind when you wheelie you are changing the orientation of the catch can so what used to be the top of the can is now the side of the can, so oil can run backwards up the hose to the filter.

I've also noticed that if my oil level is a little too high I get a lot out of the breathers. If the oil is just right I hardly get anything out of them.

There's nothing really wrong with venting them to the intake, it just makes it really oily and dirty. It technically reduces performance (very slightly) because oil in the fuel reduces octane rating, and also because if you have a certain volume of oil in the combustion chamber that means you lost a small volume of air/fuel.

The real problem I see with the oem setup on these buells is that the hot oil drops that spit out of the breathers end up hitting the IAT sensor and cause a bad reading, causing the bike to lean out.

 

[Hooker]

what is this? (the red circled area)

i took my airbox apart 3 days ago and i do not remember seeing it. My bike is an '03 XB9S with a D&D pipe and K&N filter.

 

[oh9bolt]

You shouldnt have one of those that is the interactive exhaust contoller for the 12's

 

[Hooker]

ohh haha ok! thanks!

 

[kbfnail]

Anyone have smoke come out of their breather filter?

 

[oh9bolt]

Link

 

[spazz8448]

Anyone have smoke come out of their breather filter?

i surly hope its not smoke coming out......mine starts to "steam" after a nice ride it smells like fuel vapors. i have no problem with mine.

 

[AgateJrXB12S]

Here's my breather set up with my fake NOS can that i made out of a glue stick .... I rode to every gas station and walgreens within 20 miles of my house and i couldnt find the NOS Powershot...so I made one

Works great though!

 

[Jonny5zaliv]

Just did mine the other day, only took an hour or so, super cheap, super fast.