Airhead airbox cover plate

Discussion in 'Airheads' started by alister102, Jan 19, 2011.

  1. langloisandy

    langloisandy Been here awhile

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    NC! I finally moved south!
  2. DiabloADV

    DiabloADV Semi-Occasional

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    Is this picture still floating around somewhere?
  3. Boxer Metal

    Boxer Metal Mad Scientist

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    Today's fun project. Added a breather box.

    [​IMG]

    [​IMG]


    [​IMG]
  4. Houseoffubar

    Houseoffubar fine beer sampler

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    Well clearly that wont work:wink: Looks nice!
  5. Boxer Metal

    Boxer Metal Mad Scientist

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    Ya I know it's a bit of a mess, but that's how we do stuff at Boxer Metal:D
  6. Big Al_SA

    Big Al_SA Adventurer

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    Afternoon,
    I'm new at this group and owning an Airhead, but I'm just finishing building a cafe racer, and have a small breather Filter on mine just like the very first image posted. My racebike friend and mechanic has said that unless you have problems with your Rings, (to the point where your bike is smoking heavily), there's no reason you would need to worry about "mist" or dripping of oil out that breather. If your rings are that stuffed that you're "bleeding" head compression past the rings into the crank, and then out the oil breather, then you should rather attend to getting the rings replaced\fixed, than trying to 'cath" misting or leaking oil. sounds about right to my mechanical mind, and if you're riding the bike THAT hard that you are managing to mist out the crank breather, than you should be spending the time and effort in getting the bike 'track ready" but re-doing the heads, pistons and new rings etc. :wink:

    Al
  7. Houseoffubar

    Houseoffubar fine beer sampler

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    Hey Al, normally he would be correct, but with opposed twins, there is so much pumping action, at high rpm, that Airheads tend to throw a little oil. It's not caused by blow by, but the two pistons both coming in at each other really move a lot of air out the breather, and it is prone to take a little oil with it.
  8. Big Al_SA

    Big Al_SA Adventurer

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    ok, got you.. I'll see how mine does before making further comment.. Worst case, I'll extend a pipe down to the back of the swingarm and put the filter there.
    Al
  9. rkatapt

    rkatapt Indo-Kraut

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    Whelp I am copying this from above. I just happen to have a spare laying around too.
    [​IMG]
  10. supershaft

    supershaft because I can

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    Wow. And then there is reality. I guess it all depends on which world you choose to live in! :lol3
  11. Boxer Metal

    Boxer Metal Mad Scientist

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    Here is something you can do to give you an idea of how much crank case pressure there really is. Pull both spark plugs and turn the motor over by hand with your thumb over one of the spark plug holes. The pressure you feel when the piston comes up on TDC and the valves are closed and you can multiply by 2 and add 5000 RPM's. That's what is inside your crank case for pressure. Good rings or bad rings that is a lot of pressure.
  12. robtg

    robtg Been here awhile

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    If your crankcase breather checkvalve is working properly, you will have zero pressure in the crankcase. I hooked up a vacuum/pressure guage to
    a fitting at the dipstick and had no pressure at idle and at 3000 and above the guage went to a slight vacuum. If you plug the breather hose it will slowly build up pressure.
  13. Boxer Metal

    Boxer Metal Mad Scientist

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    With this said then any pressure or oil will go past the relief valve and into his little filter?
  14. robtg

    robtg Been here awhile

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    Airflow is so low that not much oil. I had a clear catch tank on my outfit and it took a few years to a couple of ounces and some of that was water
    from condensation.
  15. Big Al_SA

    Big Al_SA Adventurer

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    Thanks for the input guys,
    thats what I thought. It must be pretty minimal if anything.. I recall when I stripped down the Bike after I got it, the airbox was "wet", but certainly no pool of oil in there.. And my breather pipe was dry, so I'm certainly not going to worry about it.
    @ Supershaft, whatever bud. You're never too old to learn something new.
  16. supershaft

    supershaft because I can

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    I hope not.

    I have been around my own beemers, beemers at the track, and other make bikes with modified breathers mostly at the track. If you rev just about any type engine a lot, a lot of oil is going to come out of the breather. By a lot I mean enough to make a mess and get oil on your rear tire. I have seen quite a few find out just how much oil comes out by running the breather straight into square airboxes versus down the carb snorkels not to mention other methods. It's enough to make a mess soon enough. I have learned that time and time again from seeing it with my own eyes. They don't make you run a catch tank at the track for nothing. That is a fact. I am just trying to help some from making a mess and possibly oiling their tire. If you rev the engine with the setup in the photos I am quite positive you will learn for yourself soon enough. Good luck!
  17. Hawk Medicine

    Hawk Medicine Coyote's Brother

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    Hey SS: At this point, I think that everyone knows what your experience is. :dhorse

    Unfortunately, you have not convinced everyone to agree with you.

    OTOH heres a solution thats both simple and sure to work. Take a water bottle, stuff some copper scouring pads inside, strap it to your subframe and run your breather hose into it. Viola!

    [​IMG]
  18. kbasa

    kbasa Roubaix! Super Moderator

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    Don't be a dick. I'm growing weary of having to follow you around cleaning up the arguments you seem to invariably involved in.

    Thank you.

    Dave
  19. Padmei

    Padmei enamoured

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    Never thought I'd ever defend SS (not that he needs defending)however I as a constant lurker have to say lately he HAS been making an effort to put forward his views in a more helpful, less antagonistic way. He does have some interesting explanations & stories & I (& others I imagine) have learnt from him as well as others on here.

    Hope this doesn't sound too patronising &/or suck arse but opinions are important.
  20. motu

    motu Loose Pre Unit

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    I think it's just that people have learned to ignore him - a pity because there is some good stuff amongst the pig headedness.