what does a head breather kit do?

[FiveStarSky]

Hi, i was thinking about buying a head breather kit,

but first i was wondering what (if any) performance it gives

how they work

and what they do

Thanks, FiveStarSky

[Blitz$M.Inc.$]

it is the cap that goes over the intake valve, they give you one with a hole in it and a tube that runs to nowhere
the idea is to relieve pressure in the head, to allow for a quicker rev
not really a performance part, id say race only
i dont have one but it seems like from others that you also need to run the free hose to a catch can
http://www.ahpminis.com/store/product_info.php?cPath=26_92&products_id=156

[125ccCrazy]

a catch can is definately a good idea, if you just put a hose on and and have it hang down there will be oil all over the place...

as far as performance, thats more of a sales tatic, they don't do much for performance, well at least any you would even notice unless maybe you were doing land speed records or something where MPH and E.T was being recorded...

For the average rider and bike they are more of an appearnce factor as they look cool if done right..

[FiveStarSky]

Okay, well i kinda made my own home-made version, borrowed from CAM2's design. Is there anyway to make oil not come out of the hose?

What i did was make a hose from the valve cover connect to a "T" barb
and connected the cam evac port to the "T" and then connected the hose that runs to the air intake (the spot where the evac port originally connected to) That way, both hoses are relived to the same spot, and gives the intake more air.

But how would i make a catch can? just hook a small cup up to the end of the hose?

[125ccCrazy]

Okay, well i kinda made my own home-made version, borrowed from CAM2's design. Is there anyway to make oil not come out of the hose?

What i did was make a hose from the valve cover connect to a "T" barb
and connected the cam evac port to the "T" and then connected the hose that runs to the air intake (the spot where the evac port originally connected to) That way, both hoses are relieved to the same spot, and gives the intake more air.

But how would i make a catch can? just hook a small cup up to the end of the hose?

The problem I see with that is that you will be sucking oil into the carb so if you notice the engine smoking or running sluggish especially at high RPM's thats why..

My question is: How do you figure that gives the engine more air??

You can make a catch can from pvc pipe and a couple end caps...

[Blitz$M.Inc.$]

lol dang its all messed up now
i would not run two vacuums to the same spot

[FiveStarSky]

Well it might not give more air to the intake, but it seemed like a good idea.

All i'm doing is trying to copy CAM2's design the best i can,
read more on my other thread here.

http://www.pocketbikeplanet.com/f30/my-100-x15-thread-45560-5.html

Should i just run the valve cap hose out and let it be an open hose?

When i ride, oil does not shoot up far enough to get to the "T" so i doubt any will get into the carb.

[CAM2]

Noone here can say they have it so how do they know what works and what doesnt........................If you guys have a problem keeping the oil in your engines then somethings being done wrong and maybe you need extra pressure releif.......Oil expands when it heats up so keep your oil levels to the lower crosshatches when its cold and you should be better.....My velocity stacks have not a drop of oil in them and as a matter of fact it does add extra air to the intake;-the extra volume of crankcase pressure released during engine operation is extra air;-is it not?

My stock 110 engine ran 9000 rpms and 435 degrees farenheight riding a 5 mile of stretch wide open..................I hooked up my breather system and my engine picked up to 9390 rpms and the temp dropped to 397 degrees according to my Vapor computer.............letting the hose hang out doesnt suck the engine heat out................not to mention my design removes the pressure by force taking away from the parachute effect on the piston on the downstroke raising rpms on the topend and it aids spooling the engine up faster and the valves run cooler when the heat can escape direct from the head instead of running all the way back to a little hole.......

I dont just do something blindly or fantasize about how things work nor do I have just 1 bike;-I have 6 superbikes now..Who here has 6 except for maybe 1 or two others?.4 are in my basement and they get taken apart and reassembled alot..Theres a total of 13 different bikes down here with me...........I do mods with comparisons and I post the top ones that work.If I posted the failures of what doesnt work I would be here all year aswell as it being a waste of words................Peace

[125ccCrazy]

if it works for you guys, Cool thumbsup2

I dont just do something blindly or fantasize about how things work nor do I have just 1 bike;-I have 6 superbikes now..Who here has 6 except for maybe 1 or two others?.4 are in my basement and they get taken apart and reassembled alot..Theres a total of 13 different bikes down here with me...........I do mods with comparisons and I post the top ones that work.If I posted the failures of what doesnt work I would be here all year aswell as it being a waste of words................Peace
Time out

[FiveStarSky]

Thanks cam, i dont have an RPM gauge or Temp monitor but there is a considerable amount of air being pushed out the tube.

I think i did a pretty good copy of your design. I made the "T" barb, connected the evac port hose and the valve cover hose to the "T" then after i get done hooking up my new air filter, i'll run the last hose into the intake.

As far as the oil, i'm thinking i may have put to much in when i last changed my oil, could that be the problem? Its only in the Valve cover hose, the rear one is fine.

[FiveStarSky]

Okay well i got it all sorted out now. Its all put together and looks pretty nice, I did what Cam said and let out some of the oil so it just comes to the bottom of the crosshatching line, now no oil spits out into the tube.

I'll post pictures tomorrow when i can get it with some sun light.

Say what you wish, but i think it was worth the time and $12 for the parts.

Thanks for all your help on this Cam2 all credit on this goes to you

[rene13]

I have one that PBU makes and I noticed it didn"t fill so congested when I had it on the engine and thats when it was stock. I plan on to put it back on since its been modded.

[The Nutty Professor]

Guys I don't think 125cc is not too far out on this one. The oil I believe he's talking about is misted very fine and would be hard to see. Yes in a clear tube you would see some dragging build up but once it went laminar it would be all but invisible. That small amount of mist would act like dust in rain clouds. Gas particles would cling to it making them larger and robbing you of horsepower. What's better the vacuum effect or a better atomized fuel mixture? One solution might be a filter of some type but how long would it last before oil build up restricted air flow dunno I thought about gravity or just making the hose so damn long it would minimize the oil problem but a quick bite of down and dirty reasoning showed me the error of that assumption. Am I saying it doesn't work? Nope I just see major problems at constant or race pace throttle.

[FiveStarSky]

Guys I don't think 125cc is not too far out on this one. The oil I believe he's talking about is misted very fine and would be hard to see. Yes in a clear tube you would see some dragging build up but once it went laminar it would be all but invisible. That small amount of mist would act like dust in rain clouds. Gas particles would cling to it making them larger and robbing you of horsepower. What's better the vacuum effect or a better atomized fuel mixture? One solution might be a filter of some type but how long would it last before oil build up restricted air flow dunno I thought about gravity or just making the hose so damn long it would minimize the oil problem but a quick bite of down and dirty reasoning showed me the error of that assumption. Am I saying it doesn't work? Nope I just see major problems at constant or race pace throttle.


well, from what i have seen while the bike is running, the little oil that does enter the tube quickly cools and condisates, and falls back into the head case, and its a long trip from the valve cover to the carb. i intentionally left the hoses rather long to help fight that problem. and i did think of some sort of filter to help screen out oil mist. But what i think people who have not done the breathers dont realise just how much air is released from the valve. And the bike is not for races, just to toot around on, I just did it as a small project to make my bike a little bit more different. But the difference is CAM2 has actual data, compared to others ideas and theorys.

The kit may not help performance, but it does its job of keeping the motor cool and relived of pressure to help the bike last a little longer.

One of you guys should try to build your own, then you will be free to talk and compare the pro's/con's.

[125ccCrazy]

well, from what i have seen while the bike is running, the little oil that does enter the tube quickly cools and condisates, and falls back into the head case, and its a long trip from the valve cover to the carb. i intentionally left the hoses rather long to help fight that problem. and i did think of some sort of filter to help screen out oil mist. But what i think people who have not done the breathers dont realise just how much air is released from the valve. And the bike is not for races, just to toot around on, I just did it as a small project to make my bike a little bit more different. But the difference is CAM2 has actual data, compared to others ideas and theorys.

The kit may not help performance, but it does its job of keeping the motor cool and relived of pressure to help the bike last a little longer.

One of you guys should try to build your own, then you will be free to talk and compare the pro's/con's.

well for your info I did do the breather from the head and had oil dripping out the hose and the hose was plenty long and above the top of the frame, The bike was rode under high and constant RPM's and not just "tooted" around so I believe I know what I am talking about but again like I said, If it works for ya, thumbsup2, all I know is I don't want oil in my carb rather it's liquid or a mist like Nutty pointed out....The reason I had the oil dripping was that I used the rear vent to opperate my fuel pump and I didn't have an inlet vent so basically I created a vacuum...

Cam or anyone else, before you point out that cars have pcv hoses going to intake manifolds don't forget that the cars have shields under the valve covers below the pcv valve to prevent the oil from being pushed (splashed) into the tube and also take a look at that hose after a while, it's full of carbon residue from the oily air (mist) being sucked into it... On the cars the opposite valve cover has a vent to allow air to be sucked into the engine while the crankcase pressure is being sucked up through the pcv valve... If you cap off that vent the engine will suck the oil right out of the head... You need an inlet vent when trying to suck the crankcase pressure out of the engine..

[swheels]

well, from what i have seen while the bike is running, the little oil that does enter the tube quickly cools and condisates, and falls back into the head case, and its a long trip from the valve cover to the carb. i intentionally left the hoses rather long to help fight that problem. and i did think of some sort of filter to help screen out oil mist. But what i think people who have not done the breathers dont realise just how much air is released from the valve. And the bike is not for races, just to toot around on, I just did it as a small project to make my bike a little bit more different. But the difference is CAM2 has actual data, compared to others ideas and theorys.

The kit may not help performance, but it does its job of keeping the motor cool and relived of pressure to help the bike last a little longer.

One of you guys should try to build your own, then you will be free to talk and compare the pro's/con's.Yep i have the setup still on my 146cc i'll post pics as soon as go dig up that motor from the garage.

well for your info I did do the breather from the head and had oil dripping out the hose and the hose was plenty long and above the top of the frame, The bike was rode under high and constant RPM's and not just "tooted" around so I believe I know what I am talking about but again like I said, If it works for ya, thumbsup2, all I know is I don't want oil in my carb rather it's liquid or a mist like Nutty pointed out....The reason I had the oil dripping was that I used the rear vent to opperate my fuel pump and I didn't have an inlet vent so basically I created a vacuum...

Cam or anyone else, before you point out that cars have pcv hoses going to intake manifolds don't forget that the cars have shields under the valve covers below the pcv valve to prevent the oil from being pushed (splashed) into the tube and also take a look at that hose after a while, it's full of carbon residue from the oily air (mist) being sucked into it... On the cars the opposite valve cover has a vent to allow air to be sucked into the engine while the crankcase pressure is being sucked up through the pcv valve... If you cap off that vent the engine will suck the oil right out of the head... You need an inlet vent when trying to suck the crankcase pressure out of the engine..Yep i had to do it the same way on my 146cc motor that's sitting in my garage.

[125ccCrazy]

Scratch the "vacuum" , (too early yet LOL) The pressure was increased at the head by blocking the rear vent (using it for the fuel pump)

[swheels]

This is the setup i did.1 because for some strange reason i wasn't getting any oil to the top of the motor.So when i routed lines to the top of the motor.i got whole lot of oil to the top off the motor now.Then i had to release some of the pressure building up in the head.But this is what i did.The is the catch can the extended black hose at the top was for the pressure release.The other line from the bottom of the bottle went back to the return line hook up on the crankcase.While another line went from the crankcase to the bottom valve cover sending oil to the top of the head.Worked out perfect for me.I can't say i noticed any performance gains.Because that's not why i did it.I just needed to get more oil to the valve train and it worked flawless.Oh plus i added a cut valve just incase if something happened.It would trap the oil in the catch can.

[125ccCrazy]

VERY ingenious S, I like that.... Run an oil cooler between the pressure line and lower valve cap to help cool the return oil and head temps... thumbsup2

Oh, how did you come to the conclusion the valve train wasn't getting enough oil?? squeeking, ticking, clattering? curious to what the engine was doing...

[swheels]

VERY ingenious S, I like that.... Run an oil cooler between the pressure line and lower valve cap to help cool the return oil and head temps... thumbsup2

Oh, how did you come to the conclusion the valve train wasn't getting enough oil?? squeeking, ticking, clattering? curious to what the engine was doing...After i few miniutes of run time.The motor would shut down and it seem to be over heating.Every time i started it, it just seemed to loose power.Then the ticking got a little louder than normal.So i decided to pull off the valve covers.I saw the cam lobes were wearing down and the rockers had changed colors from over heating.LOL WTF Brandnew motor.

[125ccCrazy]

After i few miniutes of run time.The motor would shut down and it seem to be over heating.Every time i started it, it just seemed to loose power.Then the ticking got a little louder than normal.So i decided to pull off the valve covers.I saw the cam lobes were wearing down and the rockers had changed colors from over heating.LOL WTF Brandnew motor.

wow thats messed up, any chance that the head gasket or base gasket wasn't knocked out for the oil passage?? sounds like something was plugged or restricted between the block and the head possibly...

[swheels]

wow thats messed up, any chance that the head gasket or base gasket wasn't knocked out for the oil passage?? sounds like something was plugged or restricted between the block and the head possibly...Yeah that's what i thought so i pulled everything apart and i found nothing.dunno There has been rumors that in oreder to run that motor.It needed an oil cooler hooked up.I guess it supposed to have had something to do with the oil cooler hook up coming from off the engine block.It didn't make any sense to me.....dunno So i just did what i did out of desperation cause it was a few days till the vir race.I even had to run a 110cc cam.Becuase i couldn't get another cam delivered in time.angry_red LOL

[The Nutty Professor]

That's back inline with what Red brought up a while back. A oil pump attached to a FI injector to spray a oil mist into the head. I've got it on the experiment list but to much on my plate now hahaha to even think about it.

Oh forgot to say this a oil pump attached to this system also. Every once in a while I look for a electric oil pump but I haven't found one cheap enough that I'm willing to buy and ruin if that's what happens. I going with the 3 valve for that little adventure.

[125ccCrazy]

Yeah that's what i thought so i pulled everything apart and i found nothing.dunno There has been rumors that in oreder to run that motor.It needed an oil cooler hooked up.I guess it supposed to have had something to do with the oil cooler hook up coming from off the engine block.It didn't make any sense to me.....dunno So i just did what i did out of desperation cause it was a few days till the vir race.I even had to run a 110cc cam.Becuase i couldn't get another cam delivered in time.angry_red LOL

That is wierd, someone would have to explain to me how Not running a cooler would keep oil from the head, seems to me it would put more oil to the head since it's not being routed to a cooler..

[The Nutty Professor]

Maybe adding a cooler by-passes whatever is blocked. It sounds like a machining flaw is inherent in that particular motor dunno sounded good when I thought about it. bluelaugh

[125ccCrazy]

Maybe adding a cooler by-passes whatever is blocked. It sounds like a machining flaw is inherent in that particular motor dunno sounded good when I thought about it. bluelaugh


yeah I can see where your going with that in a way but the oil is returned to the crankcase and not the head if memory serves me correctly unless it returns to a passage in the block that is diverted to the head?? I have no idea, just making guesses at this point.... I'd sure like to tear one down to see what is going on with that..... I wonder if that is why they run a oil tube from the block to the head on the YX150 along with the two oil ports for the cooler??....

[FiveStarSky]

I have a new carb comming in soon, so i will check it for any oil when i pull it off to switch them. If there is any, i'll be sure to post.

[FiveStarSky]

okay, its all finished and here is a pic of it.

I ran it for about 10mins, but i got to cold.
Seems to work okay.
I'll test it and tweek it when it warms up outside.

[Unproracer]

yeah I can see where your going with that in a way but the oil is returned to the crankcase and not the head if memory serves me correctly unless it returns to a passage in the block that is diverted to the head?? I have no idea, just making guesses at this point.... I'd sure like to tear one down to see what is going on with that..... I wonder if that is why they run a oil tube from the block to the head on the YX150 along with the two oil ports for the cooler??....

Why is it so hard to believe they just intended it to have a cooler. Maybe the head oil gallies are on the return side of where the cooler goes, w/ that port blocked off, it just doesn't get enough oil pressure from the other direction to make it up the gallies.(yea i dont care about spelling so what)

FYI PCV on cars is used not only to relieve tubulance pressure from the crank case but the rings dont seal the cylinder completely. Blow by not only brings up pressure in the crank case but allows fuel mixture from the compression stroke into your crank case. Which atomized will pick up oil particals and carbon molicules in the crank turbulance.