Drilling out JB Weld from exhaust bolt thread?

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??

[Nessism]

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.

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!

[AMK]

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.

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

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?

[AMK]

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.

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?

[chuck hahn]

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.

[gsrick]

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.

Gentleman,

I comeback for more advice on how to deal with this growing problem. It turns out that it is not JB weld, but rather a attempt at filling the thread with weld..? I haven't a clue. I have put myself on a ready to ride date in time for the Bedford meetup. So this is the biggest hurdle in my way and I'd like to get it behind me ASAP!
My questions,
I used a small diameter dremel grinding stone to grind the surface flat. Should I continue to do this or am I at a stopping point for a different method?
If I am at a stopping point what should I do next? do I drill this hole and tap it larger or do a helicoil?
Pictures to give an idea of what I'm dealing with, cause I sure don't!
Thank you for your help guys! Hoping to meet some of you and give my many thanks in person!
here is what I had to start with


Made progress!


Took a small 3/32 drill bit and tried to see if I could drill out the middle of the bolt/weld

[AMK]

Starting with a flat surface, as Kiwi says, is a must. Center punch as close to center as possible.
With a 3/16 drill bit go through the bolt as square as you can.
Find some drill bits with a left hand spiral and step up the diameter from 3/16 until you start seeing threads.
If the bolt hasn't spun out from the left hand bits you may be able to pick the threads out with a small punch and needle nose pliers.
If you see threads all the way around, unlikely but you may get lucky, then you may be able to manipulate threads out carefully with a tap.

[Kiwi Canuck]

Kodak, nice pictures and good news that it's on the end of the motor so you have some access.

From my experience in dealing with these issues, you need a flat surface that you can center punch before you try drilling, so if you can get a small rotary tool like a Dremel and fit one of the grinding stones to it, see if you can flatten the top of the broken bolt first.

Looks like whoever tried to drill it has drilled way off center of the bolt and just gave up.

It's possible they tried to JB weld another bolt onto it which would never work but maybe they tried it.

I have had some luck with using a long slim, very sharp center punch to tap the bolt around, starting at the edge and working it around, we did this on ignitions that had the security shear bolts, with the right tool, I could get those out in a few minutes each but you only get a few tries at it until you make a mess out of the edge of the bolt and no meat left to bite into.

If you try the center punch method, first use heat and lots of it, and you can alternate heat and penetrating oil, just don't breathe in the fumes.

Good luck,

[bwringer]

It's hard to tell what's going on there, but I can't think of any reason even a brain-damaged person would snap off an EZ-out and then pack the hole full of JB Weld. Then again, people do stupid things all the time, especially POs.

Supposedly you can also remove "regular" JB weld (as opposed to the high heat version) by heating it to 600 degrees F, so it might be worth attacking it with a pencil torch. There's a lot of finned aluminum there that makes a very efficient heat sink, so I don't think a large propane torch would be able to get the epoxy hot enough. If you can at least get some of it cleared out, that would help you figure out what's in there.

You might also chuck up a smallish drill bit (1/8" or so), do your utmost damndest to drill straight, and see what happens. As noted above, JB Weld and similar epoxies drill pretty easily.

[habsdoc]

EZ-outs are a lot like drill bits. You can buy lower priced EZ-outs and drill bits and have problems or you can buy more expensive quality ones and have a much better success rate. Using EZ-outs requires a good procedure, feel and the ability to recognize their limits. Machine shops use EDM machines to actually burn out broken drills, taps, and EZ-outs. But that requires the parts to be off of the bike in order to load the part into the machine.