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Thread: Frame Cracks 1976 R75/6

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  1. #1
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    Frame Cracks 1976 R75/6

    Here's another that I think is not uncommon. In other experience, is this just a simple weld job or is there some reinforcement suggested?
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  2. #2
    Administrator 20774's Avatar
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    Lew will jump in here momentarily...he has great pictures of cracking in this location if I can tell from your pictures. Here's a picture he included in a previous thread:

    http://forums.bmwmoa.org/showthread....l=1#post859169
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    '78 R100/7 & '69 R69S & '52 R25/2
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  3. #3
    Registered User lmo1131's Avatar
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    You rang?

    A reinforcing plate (mending plate) is absolutely necessary. If you just weld the crack it will again.

    Shane Balkowtisch posted a fix that Josh came up with. 1/8" thick cold roll is probably sufficient (it will certainly be stronger than the original). You need to get down to bare metal. As noted on the photo; do not weld "across" the bracket, it will just result in another crack (at some point). There was another discussion a year or so ago but I can't find it in the archives. The discussion was about whether to weld, or braze the joint. I think the final agreement was to TIG weld it.

    I also think one of our member was manufacturing mending plates... but can't remember who.

    You'll need to carefully check both sides, top and bottom of each bracket.

    Note in this image that "stud" welded onto the bracket is for the rear sets.

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

    Lew Morris
    1973 R75/5 - original owner

  4. #4
    Bluenoser
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    This bracket holds the exhaust & the rear foot peg. I'm pretty sure this is way more common than one would like to admit. I know my project bike had both sides cracked and it really looked like it has always been that way. It likely won't hurt anything to leave it alone as all the stress on this bracket is downwards, weight of passenger on pegs & exhaust. I think it looks worse than it really is.

    This is pretty good metal in this area and you have to use fairly high heat to get a good weld. When you install a brace, you transfer the stress to another location on the affected metal.
    1971 R50/5 SWB with R75/6 drivetrain
    2013 DL650

  5. #5
    Registered User lmo1131's Avatar
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    I found the image of the reinforcing plates that one of the members was offering... maybe it will jog someone's memory.

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

    Lew Morris
    1973 R75/5 - original owner

  6. #6
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    Thank you for the advice. I can make the part and TIG weld. If the repair is post worthy, I'll put up some pictures. Thanks again.

  7. #7
    Registered User krpntr's Avatar
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    comon cracks

    I have the same cracks on my frame. They were welded once but cracked again as mentioned in the previous post. That was about six years and bucu thousands of miles ago. Nothing has fallen off in that time.

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