Drilling out JB Weld from exhaust bolt thread?

[Guest]

You must have hit the bottom of the hole with the tap. I admire your persistence.
These cases command thought and patience.
The advice for a different head is good. You'll inevitably p**s off the machinist because he could have
had a berry job at first but all of his options are gone now, except for EDM.
You need to offset the price for another head with EDM now.
Although a machinist with your persistence can probably do it.

 

[Kodak]

Taking this forum thread deeper than the one I tried to tap! Appreciate everyone's input. So I've made a strong super saturated solution of hot water and alum. I tried to epoxy a flex funnel around the hole. It's leaking. I'm going to let it rest and seal it up tomorrow morning then see what happens over the next 24 hours. In the meantime if anyone has a spare head for a 1980 gs850 let me know. If it's cheaper than taking it to a unexpecting machinist then that's the route I'll go! I'm grinning inside despite my furrowed brow because I know I'm being challenged and I'm going to finally get this right.

 

[chuck hahn]

By the time you take it to a machine shop...pay them..and the down time involved youll be ahead of the game to just get another head and swap it in. Just my 2 cents worth anyway.

 

[Kodak]

Hey I'll take your two cents! I really want to minimize the down time involved in getting this going. What's a fair price for a head?

 

[chuck hahn]

Few of them on Ebay now. I would make a parts wanted section add first. The forum guys will not try and sell you a head with an issue..broke off studs, scarred cam journals etc etc.

 

[Gorminrider]

..feeling your pain.. I am scared to death of these stoopid suzuki bolts. and want the alum thing to work for when I b*gger one of mine.... Sealing the alum/water conveyance in such an awkward spot is definitely the tricky-bit...

 

[Kodak]

Well much like in roulette as is with this motorcycle. When the going gets worse double down. I'm hoping some of you will enjoy this. It's been a pain. So I've tried angling a flex funnel and using epoxy to seal it. That ended up leaking. So I decided to remove the engine. A lot easier than expected which tells me it's going to be a pain getting it back in. I built up a reservoir with latex acrylic caulk. It's chooching right now. Will check tomorrow and replace fresh alum solution.

here is the engine on its back, with the remaining tap in the hole

Here is the caulk damn I made with the solution in the hole.

 

[Kodak]

Update,

We are 26 hours in and from what I can tell very little has occurred reaction wise to the tap. Just heated up a fresh batch and flushed the hole a couple times. Going to let it go for another 24 hours and I'm the meantime I'm making some calls to machinists to see how much to zap this sucker out!

 

[hillsy]

How deep is it in the hole now? You might be able to "sacrifice" some drill bits to get it deep enough to tap a Time Sert in there??

 

[Guest]

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.

 

[Kodak]

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.

 

[JJ]

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.

 

[Kodak]

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.

 

[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.

 

[Kodak]

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.

 

[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.

 

[Kodak]

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?

 

[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!

 

[Kodak]

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?

 

[Kodak]

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.