Topic: Busted my exhaust stud >:( help needed taking the rest out.

[strangedaze39]

I was tightening my headers down after a few hours of fitting and assembling my new exhaust, and POP the nut flew off and I new right there I broke the stud. Thank god I have about a half a inch of stud to work with. No thread left.... the entire thread area busted off except for what's in the engine still. I was hoping I could just clamp some vise grips on there and take the stud out but it probably hasn't been budged since 1972 and wasn't going to budge tonight. I didn't try all my strength with the vise grips, and didn't want to mess anything else up tonight and figure I would ask here first.

How do I get this darn stud out? and I'm guessing studs are fairly common and Ace hardware is going to be a saver on getting a replacement?

Thanks for reading, sorry if it was a little long and badly worded I'm pooped (tired).

[mattcb350f]

Soak the stud in PB Blaster, wait overnight then..

Tap the end of the stud with a hammer, with about the same force you would use to drive in a small finishing nail. tap it a few times.

Don't tap too hard.......it's kind of a delicate procedure, but hard enough have an effect.

Tapping it with a hammer helps to loosen the threads (the stud is harder than the head) which will help it come out.

Then, get a good grip on it with vise grips and try to back it out. Remember that it won't take much to break the rest off in the process (search broken stud to find out).

What works for me is when the stud starts to loosen, re tighten it a bit and then loosen again. Work it back and forth but loosening it more and more each time.... and re-soak with PB Blaster.


This is very tricky at times and takes a lot of broken stud experience to know just how much force can be put on the stud without breaking the rest off. That's the best I can describe it (I've done this a couple of times on various machinery)

If it does break off........get back to us. It's very easy at that point to cause a lot of expen$ive damage in trying to drill the rest out.....but it's not imposible.

 Matt.

[Brantley]

This is one of the most fun projects you never knew you wanted to do, right? Heat and patience, my man, are the two main ingredients you need. I agree with Matt, but buy, borrow or steal a propane torch and flame that sucker up till you can see little red sparklies in the rust first. Don't blow yrself up. Then hose it down with penetrating lube after it cools. And repeat. It WILL come out. Cursing a little helps, too.

[KingCustomCycles.com]

All that was said above plus an ice cube on the stud for a few seconds after heating it. You want to shrink that stud and expand the head with the torch in the area of the threads.  Start looking for another stud as I don't believe your hardware store will have them.   

[manjisann]

I did the same thing, added a few choice words. I soaked a rag in WD-40 and left it on there while my local dealer ordered in a new stud for me. One thing to note, the stud is reverse threaded into the engine, so lefty tighty, righty loosey. When I did it after soaking it for a week or so, it came out pretty easy, didn't use heat or anything. I am pretty sure it hadn't been replaced before, but I could be wrong.

Hope this helps,

Brandon

[KingCustomCycles.com]

I just did one yesterday (CB750K) and it was conventional thread ??

[mattcb350f]

One thing to note, the stud is reverse threaded into the engine, so lefty tighty, righty loosey.

manjisann has some sort of prototype actually, I'm interested to hear more about this. It would be very confusing to find such studs in a bike.

...When I rebuilt my 350F, all the exhaust studs were conventional tread; counter-clockwise to loosen etc..

 Matt.

[okie]

In my garage are 5 Hondas: '65 CB77, '67 CB77, '74 CB350F, '80 CBX, '82 Ascot.  NONE of them have left handed threads on the exhaust studs.

[Raul CB750K1]

Reverse threads would be counterproductive, because as you tighten the nut you would be loosening the stud.

[super pasty white guy]

As an aside,

Are the exhaust studs two different lengths?  I need to replace a couple on my 750 76F and the fiche lists both 8x30 and 8x50.

thanks,
spwg

[strangedaze39]

*%$@! So I followed Matts method and on the first wrench with the vise grips (not much force at all) SNAP!!!(Edit:Read that and thought it sounded like I was trying to point fingers, it's totally my fault) Now it's all head, and I'm about to go jump off a bridge Obviously this stud was made for great things!

BTW Matts right I have a few studs that aren't stuck that you can unscrew all the way out by wrenching counter-clockwise.

Thanks for the input everyone I appreciate it, but it seems the game totally changed after I broke that protruding piece off.

I have a set of Grabits that work amazingly well for stripped/seize case/engine screws, but this is different. Don't want to mess it up anymore then it is. I could use a left hand bit and extractor but I'm nervous about them breaking in the stud because I've heard that happens often.

Any input would be crucially help.
Thanks

[MCRider]

*%$@! So I followed Matts method and on the first wrench with the vise grips (not much force at all) SNAP!!! Now it's all head, and I'm about to go jump off a bridge Obviously this stud was made for great things!

BTW Matts right I have a few studs that aren't stuck that you can unscrew all the way out by wrenching counter-clockwise.

Thanks for the input everyone I appreciate it, but it seems the game totally changed after I broke that protruding piece off.

I have a set of Grabits that work amazingly well for stripped/seize case/engine screws, but this is different. Don't want to mess it up anymore then it is. I could use a left hand bit and extractor but I'm nervous about them breaking in the stud because I've heard that happens often.

Any input would be crucially help.
Thanks

Don't know what kind of direct on access you have to the stud, depends on which one it is. If you can, I've done this before: Grind or otherwise make the wound as flat as possible. Centerpunch it with a very sharp centerpunch. Drill it with a very sharp bit about half the diameter of the stud. Come back and drill it again with a very sharp bit slightly less than the size of the stud.  At this point determine if you want to use a helisert type repair, or a Keensert type repair.

I did this on a friends GS450, used a KeenSert and all was well in little time. The key for me is very sharp tools so they dont drift, you may not get a second chance.

[KingCustomCycles.com]

Screw extractors come in various types, most of which I had not seen until my indoctrination into the aerospace vehicles world.  I like Mac tools extractors and also Snap-on.  I don't like anything tapered as it jams the threads up even more.  As stated above, you may not get a second chance so use the best.

[strangedaze39]

I have some snap on extractors coming over tonight from a friend, and he's going to help do the process. He's done it before and I haven't it makes me feel a littler more easy going about using them.

BTW I called Ace Hardware, Autozone, Advance Auto (really nice guys there), then a couple universal MC stores. Finally.... duh I realized Napa would probably be my best bet and sure enough they claimed they have 3 different kinds all 6x50 but I should bring in the nut and broken stud piece for them to check out to pick the best match.

@Super Pasty White Boy: Nope for my bike they are all the same length. You should head over to BikeBandit.com and see there parts lists/diagrams for your bike and find out exactly what you need.

[mattcb350f]

*%$@! So I followed Matts method............

Maybe I should stop giving advice now 

FWIW, the stud must have been doomed from the get go. It must have been fractured further up near the head as well.



Here's the deal with drilling out a stud......the stud is much harder than the aluminium head, and if your drill bit wonders off of the stud and towards the aluminium than it's really hard to get it back.

The trick is getting the drill bit centered on the stud, which is why MCRider says to grid or use a center punch to ensure that the drill bit goes on true.

Good luck, and sorry to hear it broke off on you SD39.

 Matt.

[okie]

I bought a bike last april that had a broken stud like that.  Yes, center-punch the remaining stud.  Drill it with the smallest drill bit you can chuck up in your drill.  Drill it with progressively larger bits.  You may not need to go this big, but, 3/16" is the largest fractional bit you can use without getting into the aluminum (assuming you are drilling exactly in the center if the broken stud).  Good luck with the extractors.  My broken stud came out in multiple pieces with the aid of various picks and tiny chisels.  I re-tapped it to clean up the threads.

Some observations I can share with you:

I bought a set of left-hand twist drills 10 years ago.  They have NEVER EVER hung up and spun a broken screw out.

Odds are excellent that the screw extractor will break off in the hole, leaving you something MUCH harder to drill out than the original broken stud.

I hope your efforts yield good results.  Patience is the most important virtue you can have in this situation.

[MCRider]

I bought a bike last april that had a broken stud like that.  Yes, center-punch the remaining stud.  Drill it with the smallest drill bit you can chuck up in your drill.  Drill it with progressively larger bits.  You may not need to go this big, but, 3/16" is the largest fractional bit you can use without getting into the aluminum (assuming you are drilling exactly in the center if the broken stud).  Good luck with the extractors.  My broken stud came out in multiple pieces with the aid of various picks and tiny chisels.  I re-tapped it to clean up the threads.

Some observations I can share with you:

I bought a set of left-hand twist drills 10 years ago.  They have NEVER EVER hung up and spun a broken screw out.

Odds are excellent that the screw extractor will break off in the hole, leaving you something MUCH harder to drill out than the original broken stud.

I hope your efforts yield good results.  Patience is the most important virtue you can have in this situation.

And I like Okie's suggestion of starting with a smaller bit and using more stages to get where you're going. I was buying carbide bits from Lowe's so I didn't want to buy a bunch, but they are always good to have. And then just before you get to full size, stop and as suggested pick at the remains of the stud to get it out. Clean it up with tap and good to go.

 I had plenty of room to work on the GS, single downtube frame, so I just drilled it completly out and put a Keensert in.

[manjisann]

Err, Umm, maybe it wasn't reverse threaded, but I swear it was    I have broken several screw extractors of in various things and the one thing I learned was to use the biggest one you can safely use. I am not saying the idea of drilling it and then picking out the pieces is bad, just different means to the same end. Whichever way you choose, I wish you the best!

Brandon

[strangedaze39]

@Matt, I know I read that and I thought hmmm that sounds like I'm trying to say it was his method that made it worse. Not at all, your right that stud is CA..RAP.

Update: I got my buddy over with the snap on extractors, drilled it first with a smaller set (about half the size of the stud) the extractor spun out of spot with some real force on it. Next I tried size up with is just ever so slightly smaller then the stud. Same situation there, spun out and left me with nothing left to try as far as extractors. The stud is looking uglier then ever now, almost as if it was one with the engine. My buddy said he'll get a tap and die kit Monday and we can just bore it smooth and re-tap it. The thing I'm worried about here is if the angle of the new thread is off, that flange wont fit on correctly and I imagine it could make a weaker seal in the end, but I might be wrong. Maybe I can get it right that way, who knows.

@Okie, do you think it's to far gone to try and use your method? Sounds like it could work and salvage most of the existing thread allowing a confident tap(die?) of the old socket. I'll print out this thread and see what I can do today without sacrificing any more mess-ups. I'll just have to take it slow.

@MCRider, I was thinking about using one of those studs you suggested before I'm going to look into them a little closer.

Thanks everyone for the input  I know this will turn out right......eventually.

[strangedaze39]

@MC you mean keysert?

[MCRider]

@MC you mean keysert?

No its a brand name "keensert", the far right on this page http://www.ondrives.com/products.asp?subcatid=163

It requires a hole larger than the original, tap it out (tap comes with the kit or its a standard size, then you thread in the keensert and drive the little spikes in to lock it in place. Its hardened steel and much tougher than a helicoil. You still have the problem of drilling the hole true, etc.

Usually available at your better auto stores. NAPA etc.

Or here: http://www.barnhillbolt.com/index.php?root=menu&level=&menu=1982&catid=-1&custid=694206562

[okie]

Bolt the finned exhaust collar in it's normal position over the port using the existing good stud and nut.  Use the other hole in the collar as a drill guide and you should  be close enough to straight that a crooked stud won't be an issue.  The idea is, if the drill bit fits through the collar, the stud will fit through the collar too.  If it were mine, I would still try to pick the rest of the old stud out the way I suggested before. 

[MCRider]

Bolt the finned exhaust collar in it's normal position over the port using the existing good stud and nut.  Use the other hole in the collar as a drill guide and you should  be close enough to straight that a crooked stud won't be an issue.  The idea is, if the drill bit fits through the collar, the stud will fit through the collar too.  If it were mine, I would still try to pick the rest of the old stud out the way I suggested before. 

That's a good idea!

And I'll add you may want to keep the Keensert as your last resort. Try Okies's pick it out and retap it first, then if that's not going to hold, drill it a bit bigger for a helicoil, and the final try, though it will be the strongest, is the Keensert.

[gasshog2]

I've been looking to install 4 into 1 exhaust on my 750 K8, but after reading this I'll probably leave well enough alone.   GOOD LUCK with getting that STUD FROM HELL out...

[babyhuey]

Well, i just broke a stud off and i was trying the ez out method (i know i shouldnt have looking back) and the ez out broke off, anyone have ideas on where to go to now?   I dont have access to a welder and its down low enough that a welder probably wont work anyways