Rebuilding petcocks

Discussion in 'Old's Cool' started by walkingbear, May 1, 2010.

  1. walkingbear

    walkingbear Lets Play Chicken!

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    89 R100GS tech question
    Never rebuilt a set of petcocks before. What do I need?
    #1
  2. east high

    east high Been here awhile

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    Rebuild kits and some carb cleaner? If they're anything like the spring loaded, screw on petcocks on my /5 you'll also need a beer or two and something to huck across the garage..
    #2
  3. Rob Farmer

    Rob Farmer Long timer

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    Brilliant :lol3 Just rebuilt a pair on my /7 so I know what you mean.
    #3
  4. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    On the later airheads, they are either Germa or Karcoma and are rebuildable. Hucky, for example, sells rebuild parts.

    http://bmwhucky.com/

    Use silicone grease to lubricate everything.

    The older petcocks (the Everbest on the /5's) not easily rebuildable and should be done only if you need the "correct part" for a restoration.
    #4
  5. east high

    east high Been here awhile

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    Yes, forgot to menton that mine were of the Karcoma variety.
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  6. Beater

    Beater The Bavarian Butcher

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    I just did a set from my /7 ... If you have a 15mm bicycle wrench .. the kind that's made by a stamped out piece of sheet metal ... Like this:

    [​IMG]

    You can use the pointed ends of the wrench to open the petcock ... really easy.

    The rebuild kit contains three gaskets. The first is a circle with three holes in it. The next is an o-ring. These two are must's to be replaced and are both interior to the petcock. The third is a cork seal that seals the seal in between the petcock and the tank ... this one is difficult and I wound up making one that worked infinitely better out of an 1/8" rubber sheet (from a DIY gasket kit).

    The first petcock took me ~15 minutes to do. The second one took me 2. Easy and no more leaks!!!
    #6
  7. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    Wouldn't bother with the fiber gasket between the petcock and tank. Later models use a mesh strainer screen with a built-in aluminum washer that fits over the inlet straws of the petcock in the tanks. Good addition.

    16 12 2 307 112 strainer petcock 1970 on $ 6.75
    #7
  8. Hawk Medicine

    Hawk Medicine Coyote's Brother

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    I've saved the petcocks every time I'v broken up a bike or sold a tank, so I have a bagful of em.

    A couple of weeks ago, I was caught up on the R-90 and looking for something to do, so I began disassembling, cleaning and rebuilding petcocks. A day soaking in Pinesol got em pretty clean and a tiny burr on a Dremel tool got at the oxidized crud down below the tubes. After that, it was just a matter of taking each one apart, checking the condition of the parts and then reassembling them.

    Now, after an evenings work, I have a lifetimes worth of good petcocks! and only a few things got thrown across the room!
    #8
  9. Chobro

    Chobro spinning the wheel

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    I'm rebuilding my Karcoma taps, with parts from Hucky, so I lube just the the rubber bits and not the felt washer, correct?

    Can I use a silicone spray lube or is dielectric grease better?
    #9
  10. Wirespokes

    Wirespokes Beemerholics Anonymous

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    The spray isn't very thick and dries out quickly. The grease will last much longer. Silicone grease is much cheaper than dialectric - get it at a bearing supply house in a large tube for eight bucks.
    #10
  11. Chobro

    Chobro spinning the wheel

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    Will do. Thanks!
    #11
  12. Yarddog

    Yarddog Been here awhile

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    For $41.95 for new, I didn't think it was worth the effort to rebuild mine...
    #12
  13. richardak

    richardak Been here awhile

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    Maybe so but the rebuild "kit" was $10 each and it didn't take me more than 5 minutes apiece. I can find other things to do with the $60...:1drink
    #13
  14. Wirespokes

    Wirespokes Beemerholics Anonymous

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    I've taken them apart many times and not even replaced anything - just cleaned them out, polished up the valve - and put them back together and they've worked fine.

    No need to frighten everyone off thinking that new ones are the only way to go.
    #14