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Thread: Drilling out JB Weld from exhaust bolt thread?

  1. #11
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    I would keep drilling with the bit you're using and see if it keeps drilling. Stick the bit in one of the other holes first and put some tape on it where it bottoms out to keep from drilling to far. If you make it to the tape line bump the size of the bit and drill it again. Keep at it till you get to a bit that fit well in the other holes then try running the proper size tap and see if you can chase the original threads.
    GSRick
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  2. #12
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    I take my MIG welder and lay a fat spot weld on those broke exhaust bolts. The weld will not stick to the head and it hurts nothing. Let the first fat spot weld cool and do another right on top of the first. Repeat the process till there is enough past the head surface to grab with vice grips. The heating and cooling of doing the series of spot weld help crack the corrosion seizing the bolt too.

    Oil the crap out of it with your fav penetrating oil and start working it back and forth to use the threads to grind up the crud in there. Youll soon see its getting easier and easier to move the stud...then slowly start removing it ..work back and forth and be patient.
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  3. #13
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    Quote Originally Posted by gsrick View Post
    I would keep drilling with the bit you're using and see if it keeps drilling. Stick the bit in one of the other holes first and put some tape on it where it bottoms out to keep from drilling to far. If you make it to the tape line bump the size of the bit and drill it again. Keep at it till you get to a bit that fit well in the other holes then try running the proper size tap and see if you can chase the original threads.
    Ok great this is what I'll do, notice that the beginning of the thread is now oblong and larger than the bolt, will that be a problem with having the bolt back out?
    1980 GS850G

  4. #14
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    Quote Originally Posted by Kodak View Post
    Ok great this is what I'll do, notice that the beginning of the thread is now oblong and larger than the bolt, will that be a problem with having the bolt back out?
    That won't be a problem.
    Alan


    Weaned on a '74 450 Honda
    Graduated to an '82 GS850GL
    Now riding an '83 GS1100GL
    Added an '82 GS1100GL

  5. #15
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    Update, because the problem stud is the 3rd cylinder that is closest to the frame I need to move the motor an inch or two. Can this be done or will I have to take the engine completely off the bike. Am I better off removing the swing arm or removing the drive shaft from the tranny?
    1980 GS850G

  6. #16
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    Ok, I went ahead and shifted the engine enough for me to get proper clearance to continue drilling a straight hole. I'm getting very close to the full depth of the bolt and it seems like I'm drilling through something. The hole I've drilled is smaller than the diameter of the bolt. Should I go larger and over size the hole and tap it or stick with the size I've drilled and tap that? Pics showing the depth and diameter of the hole I've drilled
    https://i.imgur.com/5BYzGx4.jpg
    https://i.imgur.com/ZJvnUue.jpg
    1980 GS850G

  7. #17
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    Step the drill size up until you just barely see the threads on the bottom side of the hole. You can then use a Dremel tool to grind a groove in the top side of the hole. Then with a punch or a small chisel type tool (you may need to grind something into shape) you may be able to "pick" the two halves out. Then clean the original threads out with a tap.
    Alan


    Weaned on a '74 450 Honda
    Graduated to an '82 GS850GL
    Now riding an '83 GS1100GL
    Added an '82 GS1100GL

  8. #18
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    Quote Originally Posted by AMK View Post
    Step the drill size up until you just barely see the threads on the bottom side of the hole. You can then use a Dremel tool to grind a groove in the top side of the hole. Then with a punch or a small chisel type tool (you may need to grind something into shape) you may be able to "pick" the two halves out. Then clean the original threads out with a tap.
    Excellent. This is the route I will go. Appreciate everyone offering insight. Love this forum!
    1980 GS850G

  9. #19
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    You gotta get more in the center of the old screw. And pick up a LH drill set from Harbor Freight. As the shell of the bolt gets thinner it will spin out from drilling torque. That's the beauty of the LH bits.
    Ed

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  10. #20
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    Well I took a stroll up **** creek today. Got a nice 7/16 hole drilled. Started tapping with a 8mm 1.25 tap, got about 5/7 of the way maybe 13/17 or 17/21, take you're fractional pick. Met some resistance, haven't tapped a bunch before so I don't know how much torque is too much for knowing when to stop and reevaluate. I know to one turn quarter turn back. Well she snapped like a dry branch. Flush break. Can't get a grip on it. Most of the tap is in there. Any thoughts? Should I buy a Walton extractor and try that??
    1980 GS850G

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