Identifying BMW Airhead petcock model?

Discussion in 'Airheads' started by shadeobrady, Apr 1, 2019.

  1. shadeobrady

    shadeobrady Adventurer

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    Hey folks - having issues with gas flow and want to do a rebuild. As I understand it, the main two types readily available are the Karcoma (a new version of the original?) or the Everbest (the newest version?).

    The bike is a 1978 BMW R100RS if that matters for any reason.

    Is there anyway to know which these are so I can buy the correct rebuild kits?

    petcock-1.JPG petcock-2.JPG petcock-3.JPG

    Attached Files:

    #1
  2. PaulBarton

    PaulBarton Long timer Supporter

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    #2
  3. brfoster

    brfoster Baile Atha Cliath

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    @shadeobrady, the petcocks in the photos are Karcoma - the latest version.

    Everbest were usually fitted to early models ('55-69).

    See here for more detail:

    http://w6rec.com/duane/bmw/petcock/
    #3
  4. shadeobrady

    shadeobrady Adventurer

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  5. chasbmw

    chasbmw Long timer

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    The original peacock should have the outlet pointing downwards......

    Before you order new parts, drain the tank, remove the taps and remove any watered grunge swilling in the bottom of the tank, then check again for flow.
    #5
  6. bmwrench

    bmwrench Long timer

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    The petcock used for a while, most notably in 1980 was the Germa. It is identified by the screw that retains the handle.
    #6
  7. dirtsurfer

    dirtsurfer Adventourer

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    A few more pictures and I might be able to identify it
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  8. boxerboy81

    boxerboy81 Stay Horizontal

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    [​IMG] [​IMG]
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  9. Disston

    Disston ShadeTreeExpert

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    You have Karcoma petcocks. They may only need cleaning. There are only 2 parts available if needed. An O-ring and a flat rubber disk with 5 holes. If anything else other than these 2 parts is needed you have to buy a new complete part.

    Most times all that's needed is a good flushing with compressed air and a flush of the debris in the gas tank. Get some new gas line too. The GL doesn't last very long.
    #9
  10. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    The lower brass or aluminum washer connected to the screen can wear and not seal well.. those should be replaced as well.
    #10
  11. Disston

    Disston ShadeTreeExpert

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    Right Solo. The filtration of the system is a large screen inside the tank that is held on top of the petcock straws and sealed by a metal washer on the modern screens and a separate red fiber washer on the old ones. You can still buy the red washers if that's what you have and they are worn out but the newer screen with a metal washer is one piece so if worn out you have to buy the whole screen. No problem really they only cost about $10. If the older screens are ratty just buy the modern ones.
    #11
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  12. Manks

    Manks Been here awhile

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    I have two Germa taps for my big tank. did they make a right angle outlet (where the hose attaches) for these?
    #12
  13. chasbmw

    chasbmw Long timer

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    And clean the internal screen NO 3 on the diagram
    #13
  14. Disston

    Disston ShadeTreeExpert

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    If you have one. Not all petcocks have the small screen in the bottom.
    #14
  15. shadeobrady

    shadeobrady Adventurer

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    Thanks folks - this was all incredibly helpful. I yanked them off... both had the screen filters that plug upwards into the gas tank. Disassembly was pretty easy besides getting that end with the incredibly strong spring screwed back on, but not terrible.

    The gas flows - we're good!!
    #15
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