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Carb pillars and JB Weld

Discussion in 'XJ Technical Chat' started by cds1984, Oct 12, 2019.

  1. cds1984

    cds1984 Active Member

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    Just because I never thought I'd attempt this.
    Pics... MVIMG_20191010_074924.jpg MVIMG_20191010_074948.jpg MVIMG_20191011_085409.jpg MVIMG_20191011_085336.jpg
     
    Jetfixer, Franz, Polock and 1 other person like this.
  2. XJ550H

    XJ550H Well-Known Member Premium Member

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    put some jb in a jar of fuel when it starts to break down you will know its time to redo your fix
     
  3. mlew

    mlew Well-Known Member

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    That will work. I have a JB weld patch in my VW gas tank, its been there for 6 years.
     
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  4. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    A patch on a crack is under less stress than a float pillar. That repair will fail eventually, but should last a year or two if the surface prep was done well.
    Personally I would have tapped and threaded the stub for a bolt instead.
     
  5. cds1984

    cds1984 Active Member

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    The funny thing about this fix was that the carb pillar was broken for a few years and the pin actually was, and is again, fixed in from the other side, not like in the picture.

    The full story is,
    I did an engine upgrade from 853cc to 891cc so while I was there I changed that single carb body out.
    The bike would lose the idle circuit when hot... so after many iterations of jet changes, slide hole drilling, spring snipping, air box restriction, etc etc... I downgraded the engine back to the 853cc, the idle circuit issue has persisted so...
    Good thing I have spares, in my shed.

    In saying all of that, I did use a 1mm drill and put a slightly angled drill hole about 2mm deep into each side of the pillar's top before the fix and also filed down the top, just above the pin hole bottom, to raw shiny magnesium.

    That pillar is so damn tiny, I was at a loss on how to fix it.

    I did try a bit of aluminium mig wire and an oxy/acetylene set to try and build on top but couldn't bring myself to put that much heat into the pillar.

    Now the carbs are back in after the wet set, sync and colour tune.
    So today the truth of the real reason for doing it will, after I take it out for a ride, make itself known!

    You can't say I don't know how to make extra work for myself! (and yes it was me who originally broke the pillar *sigh*)
     
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  6. cds1984

    cds1984 Active Member

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    Quick follow up if you read the last post, re: idle circuit.
    Culprit was the TCI in the end haha... oh boy.

    Carbs are working good also, mind you.
     
  7. Jetfixer

    Jetfixer Well-Known Member

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    I have used JB weld to repair many things , I have an aluminium after market engine case in my 71 beetle , the oil sending unit boss cracked . I used Jb weld and liquid steel has lasted 8 years now . The liquid steel is really good stuff and sets up fast and is fuel and oil resistant....if you fully clean and let it cure around 12 hrs .
     
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