Drilling out JB Weld from exhaust bolt thread?

I understand what your guys are saying. I know the largest cost so far is the sunk time instead of working on the seat pan and electrics. Fortunately I don't have too much sunk into the tap removal. But you're right about having it for life. I just have to take into consideration when I'll be needing an M8 timesert as opposed to using the carbide burs again that I've just ordered. I will say for as much complaining I've done while drilling this sucker out I'm having a peachy time learning as I go and from everyone chiming in on this thread. I've learned about the various ways to grind out a tap, learned about EDM, tempering, and the cost of not drilling out a bolt all the way before tapping threads! This is what I signed up for when I bought this bike!

[hillsy]

Those timeserts are pricey. Ain't happening. 70 bucks for a couple taps and a steel insert?!

How much have you sunk into it so far with broken taps, extractors and drill bits? Like Chuck said, you'll have the tools forever and anything you do after this will only cost the price of the inserts.

[chuck hahn]

Yeah but aftr the initial purchase you just resupply the inserts. Compared to a coiled style helicoil its like a Bently compared to a VW bug.

Those timeserts are pricey. Ain't happening. 70 bucks for a couple taps and a steel insert?!

[hillsy]

Giving this all I got. Had a small carbide burr I found and that actually did something then I used my dull carbide end mill on a hand drill and got about a third of the way down. Should I use cutting fluid with a carbide burr? I tried it both ways and didn't find any particularl success. Also what's the next appropriate size tap up from M8. I was thinking 3/8. M10 seems too big for the space I have and M9 is impossible to find as a button cap bolt. Hoping fresh burrs coming this Friday will be the trick. Going to paint the engine while it's off the bike.

Use a TimeSert or Helicoil and bring it back to M8 - then Loctite M8 studs instead of using bolts.

Giving this all I got. Had a small carbide burr I found and that actually did something then I used my dull carbide end mill on a hand drill and got about a third of the way down. Should I use cutting fluid with a carbide burr? I tried it both ways and didn't find any particularl success. Also what's the next appropriate size tap up from M8. I was thinking 3/8. M10 seems too big for the space I have and M9 is impossible to find as a button cap bolt. Hoping fresh burrs coming this Friday will be the trick. Going to paint the engine while it's off the bike.

Bring that som'bich over here to Youngstown Ohio. I'll show you boys how to get that busted tap out of there!

If you weren't on the wrong side of Ohio I would! Alright going to order a set of carbide cutters, any specific type I should look for?

[storm 64]

Bring that som'bich over here to Youngstown Ohio. I'll show you boys how to get that busted tap out of there!

A carbide cutter will cut that tap. with the engine on work bench you can use a 1/8 carbide cutter in a dremel or die grinder . cut a 'trench' down the center and stay away from the sides of the hole. Pick up a double cut carbide cutter from industrial house. Dip cutter in oil every 60 seconds or so to not over heat cutter. This will keep cutter sharp much longer too. use motor oil, it works fine. Take your time and you can cut this thing in half and pull it out of hole with long nose pliers. Done this many times. All you want to do is cut a thin 'trench' down the middle or as far as you can and pull the pieces out as you get deeper in the hole. You can get that out. I have had to drill out lug bolts on center and use this method to cut out lug nuts from the inside that were rounded off (not mine) Carbides are a great tool to have around. Try this before you go to machine shop, that is how I would fix this in my machine shop. Have some good luck there.

So the industrial cobalt drill bit isn't doing squat. Maybe it's not a high enough %cobalt. So how much is one of these carbide bits? Is double cut carbide cutter the name to use when I go looking for it? Run it on my drill press or drill at low speed?

[headsbikesmopars]

A carbide cutter will cut that tap. with the engine on work bench you can use a 1/8 carbide cutter in a dremel or die grinder . cut a 'trench' down the center and stay away from the sides of the hole. Pick up a double cut carbide cutter from industrial house. Dip cutter in oil every 60 seconds or so to not over heat cutter. This will keep cutter sharp much longer too. use motor oil, it works fine. Take your time and you can cut this thing in half and pull it out of hole with long nose pliers. Done this many times. All you want to do is cut a thin 'trench' down the middle or as far as you can and pull the pieces out as you get deeper in the hole. You can get that out. I have had to drill out lug bolts on center and use this method to cut out lug nuts from the inside that were rounded off (not mine) Carbides are a great tool to have around. Try this before you go to machine shop, that is how I would fix this in my machine shop. Have some good luck there.

Pretty sure I have an 82+ GS850 head and matching valve cover (combination good for all years 850) if you need one. Shipping may be costly though.

I am interested. I'll try to get back to you tomorrow if this doesn't turn out.

[JTGS850GL]

Pretty sure I have an 82+ GS850 head and matching valve cover (combination good for all years 850) if you need one. Shipping may be costly though.

Looks like I'll be doing just that. Machine shop said they'd take a look. So I'm loading up the whole engine tonight. But first trying to do what metal fab suggested as I wait for an extra hand to load it up. Worth a shot.

Easiest and quickest thing to do at this point is to either remove the head and take it to a machine shop that had an EDM, or to replace the head.

Easiest and quickest thing to do at this point is to either remove the head and take it to a machine shop that had an EDM, or to replace the head.

I just saw your post, I have done a lot of jobs like this. If it was me I would stop where you are now and get an M42 cobalt drill bit. The M42 bit is tool steel with cobalt in it that makes it harder than heII, and it is coated with titanium nitride. An M42 bit will cut any normal tool steel tap. That said you have to run the M42 bit real slow like 100 RPM's and use oil on it when you are drilling. If you turn it any faster or dont keep it oiled while drilling the tap is hard enough to burn up the M42 bit. The harder the metal you are cutting, the slower you have to rotate your cutting tool.

Odds are there was a flake of the old bolt in the hole, one little piece of steel left off of the original bolt will lock the tap in place where you cant hardly get it out without breaking the tap. It took a lot of force to break the tap, if you could get a good enough grip on it the odds are the tap would just break again. I dont think you can get it to move. Chips could have locked it up too.

If you totally screw it up you can have the hole filled with aluminum and re drill and tap it. If it goes beyond drilling out the tap you should probably just replace the head. Compared to the work you have done replacing the head isn't that bad. Don't use a helicoil use a steel insert that is solid, a helicoil is like a spring. The solid inserts are far superior. Don't break the cobalt bit, it is almost impossible to drill out, only carbide will cut it. Most hardware stores will carry M42 bits.

Can I purchase M42 at a lower or Ace Hardware. Also what about the fact that my tap isn't broke flat. It's sorted of jagged. I've tried center punching it but I'm breaking my center punches.