Fork pipe failure

Discussion in 'Tech Area' started by Tripod, Dec 7, 2018 at 3:01 PM.

  1. Tripod

    Tripod Member

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    While following racerX's instructions on refilling the k1 front forks, i noticed one of mine was bleeding air when compressed. Forks were rebuilt with new gaskets and o rings.

    I noticed that there were bubbled coming up from the area i circled. Is this failure common?
     

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  3. kirrbby

    kirrbby Well-Known Member

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    You probably just need a new o-ring on there. The o-ring makes the seal.
     
  4. Tripod

    Tripod Member

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    I probably should have posted a better picture. I attached the schematic for the leg. The area in yellow is where the leak is. A few pinhole leaks that bubble out fluid after compressing the leg. The first picture is misleading without having the leg in front of you.

    Agreed, the o ring is what forms the seal, the portion of the leg that the bolt threads into appears to be a press fit. And that flat area is where the leak is.
     

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  5. red69

    red69 Well-Known Member

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    Is there any corrosion inside that pipe? If so, a good o-ring will not seal.
     
  6. kirrbby

    kirrbby Well-Known Member

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    I've never seen, or heard of that problem before Tripod. It seems odd, and unlikely, that there would be pinholes in that location.
     
  7. racerx

    racerx Administrator
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    Yeah, that's a new one on me too. If...and that's the operative word...it's simply a pinhole in the press-fit & welded joint, then it shouldn't take much to seal it. With no structural stresses involved, and with the top of the inner fork leg far away from the "business end" of things, brazing the area should be straightforward - and permanent.
     
  8. ctbale

    ctbale Member

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    Thats a first. That threaded sleeve is, like racerx said, pressed in. maybe brazed or soldered also? There should be a air space above the oil column when the forks are compressed so that much oil makes me think too much oil is "another" issue. I vote for brazing also. But thats a first!!!
     
    #7 ctbale, Dec 9, 2018 at 1:35 AM
    Last edited: Dec 9, 2018 at 1:50 AM

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