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Thread: 1971 /5 Krauser Bag Frame Weld Repair

  1. #1
    Motomark motomark's Avatar
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    1971 /5 Krauser Bag Frame Weld Repair

    The tubular frame on my /5 that holds R/H Krauser bag has a tab that holds the tail rack on it that needs to be welded where a stress crack has formed.My inquiry is what is the best kind of weld for this type of repair?Not too sure what kind of metal was used.I have the black painted type of carrier so I cant see under the paint to determine if its steel or a alloy.I do know that where the stress crack is it has rust on some of the cracked surface.Would appreciate any input,don't want to use wrong kind of weld and cause a worse problem.
    Thanks
    Mark

    1971 R75/5,1990 K75RT,1994 K75,1999 KLR

  2. #2
    Sir Darby Darryl Cainey's Avatar
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    I think most of the racks were Braised with bronze.

    Any competent welder should be able to do this!
    Ambassador BMW MOA Ontario Canada
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    1977 R100RS, (Retired) 1993 R100GS (just getting started)

  3. #3
    Registered User lmo1131's Avatar
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    "Alloy" (aluminum) doesn't rust.

    As Darryl stated, they're steel, and brazed. In my experience, once something has been brazed, it will have to be brazed if it needs repair; the brass and flux penetrates and contaminates the steel making it a PITA to "weld".

    I'd suggest pulling the whole rig off the bike and having the frames bead, or media, blasted to see if there are any other cracks starting to develop. When I bought my Krausers (used) I was going to have them stripped and powder coated. Once the powder-coater got the old finish off we found a couple of "iffy" joints.

    Post a few shots if you have time. I'm curious as to what "vintage" your hardware is. Duane Ausherman maintains a "Krauser" thread, and he's always looking for images.

    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  4. #4
    R100GS, '89 Guenther's Avatar
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    I have a friend who has a muffler shop. The welder there just used a grinder to strip off the paint and put some "blobs" on it. I painted it over with black paint. Holds just find and I can't even remember how long ago this was done.

    /Guenther

  5. #5
    Monza Blue 1974 R90/6
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    Lew, is that your rack in the picture you posted? Looks like mine (except I have chrome), but I never knew what brand it was. I have BMW city cases.

    Barron

  6. #6
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    My 2 cents

    I have the exact frame, and someone before me "brazed" it in several places - appeared to be whoever had it before me carried something on the back "deck" and they put in some supports.

    When I cleaned off a ton of paint, I found a hairline crack at the point where it attaches to the behind-the-seat frame mount.

    My suggestion: don't braze, but have it tig welded. Much nicer job, cleaner looking, and stronger. Once you braze, which isn't that strong, you will never be able to weld anywhere near it.

  7. #7
    Registered User lmo1131's Avatar
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    Yeah Barron, my rack.

    Jimmy, I agree, TIG puts much less heat into the structure than brazing would.

    I've seen some Krauser hardware that looked "welded" (by virtue of the size and shape of the bead) ... maybe they switched at some point (?)
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  8. #8
    Motomark motomark's Avatar
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    Quote Originally Posted by lmo1131 View Post
    "Alloy" (aluminum) doesn't rust.

    As Darryl stated, they're steel, and brazed. In my experience, once something has been brazed, it will have to be brazed if it needs repair; the brass and flux penetrates and contaminates the steel making it a PITA to "weld".

    I'd suggest pulling the whole rig off the bike and having the frames bead, or media, blasted to see if there are any other cracks starting to develop. When I bought my Krausers (used) I was going to have them stripped and powder coated. Once the powder-coater got the old finish off we found a couple of "iffy" joints.

    Post a few shots if you have time. I'm curious as to what "vintage" your hardware is. Duane Ausherman maintains a "Krauser" thread, and he's always looking for images.

    Lew,
    Thanks for the reply.My luggage carrier looks similar to the photo you posted,but is a three piece assembly.R&L halves bolted to the rearsubframe and center mounted rear rack that attaches to the R&L halves.Has BMW stamped on end that connects to upper shock mount bolt.I will use a dremel with a wire brush and remove the paint around the stress crack and nearby weld and see what color the weld is.I guess a brazed joint will be a brass color.
    Mark

    1971 R75/5,1990 K75RT,1994 K75,1999 KLR

  9. #9
    Registered User lmo1131's Avatar
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    I guess a brazed joint will be a brass color.
    That is correct.

    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

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