Exhaust bolt extraction

[Guest]

Following is the story of my stupidity and hopefully some hints on a resolution.
First-stupidity:
...having already put 800+ miles of fun (even though mostly commuting) on the 850G this past month, I didn't leave well enough alone. The bike had 1 exhaust bolt busted off the #4 cyl when I got it, but the pipe was still nice and tight from the remaining good bolt and almost 30 yrs of frozen rust. But, I decided to test the waters and see if the #3 cyl bolt would unscrew after plenty of penetrating oil and tapping. Why?...because I was feeling brave(or stupid) and wanted to see how difficult these bolts would come off, to replace them and also fix the one broken one. SNAP! bolt breaks on #3 cyl, so I leave well enough alone as that exhaust pipe was still solidly snugged up. Tell self...wait til winter for this project. My plan worked until this past Fri on my commute home from work in the pouring rain, I hear a distinct metal clink at a stoplight and a slight bogging of the bike. Not being in a good situation between rain and traffic to stop and investigate, I pushed on for the 20 mi ride remaining and would look at the bike in the comfort of my garage later. Bike still ran good but, would stall at idle unless I kept the throttle up around 1500rpm and slightly bog down on initial acceleration.
Later, I checked it out and found the #3 cyl flange was slightly loose allowing the header to back off ever so slightly and expose an exhaust leak causing my problems. Well now I have to proceed cautiously to try to free up the remaining bolt to then see if I could tighten for a temporary fix til winter. Penetrating oil, tapping and then some heat and 1st attempt. Yeah, it started to move then...SNAP...both broken and now on to some serious thinking (and choice words for my unwise actions). Debating on taking the head off or parting the stupid bike out, I went to bed. Waking up early, I decided to give an attempt at fixing the situation with the bike intact. No room to get a pair of locking pliers in there on one remaining bolt (looking like a 1/4" protruding stud at this point) and the other being broken flush with the head, I decided to DRILL and then tap it out.
So in my pics the drilling phase is done and now on to the tapping stage.
QUESTION – I know the original bolt is an 8mm width but am unsure of the length. I drilled 3/8” into the head and can just start to see the aluminum poke through the old steel of the bolt. Someone have that length so I don’t go too deep and buy the correct replacement allen bolts at the local hardware store???...or do you recommend putting studs in and use new locking washers and bolts?
Here are some pics of the tools I used and the newly drilled out holes. After locating the right taps I will give you another update on my saga. BTW, the stud extractors (red circled) in the pic didn’t help. The 3 drill bit sizes are in the pic that I used along with a chuck extender. Made sure and put duct tape around the exhaust pipe so as to not bugger it up with the drill chuck spinning. Had to turn the front wheel all the way to the right for room to maneuver. 2 hours later while trying to maintain proper angle of drilling I tink I'm done. The wooden dowel was my depth checker marked off in 1/8” increments (yellow circle) and marked in red for the present depth drilled. The old broken bolt is circled in red.
I wouldn’t recommend doing this with the head in place, and will have to be real careful with keeping the tap straight, but I’m planning on getting this bike back on the road quickly…..then I’ll have time to finish the job come the snow time.
Don’t be stupid like me, but maybe this procedure might help someone out there?...sorry for the long read!

[67fire]

For future reference, I use left-handed drill bits to remove broken bolts. Most of the time, it catches the remaining bolt and screws it out.

Eric

[teet]

I'm following this thread, as I too have a broken flange bolt. Thankfully the head just snapped off for the previous owner, so I have some meat to grab onto, and It doesn't leak yet....

Keep us informed of your progress..

Jeff (teet)

[reddirtrider]

If you drilled 3/8" into the bolt and are hitting aluminum your not bottoming out, you're drifting off center. Stop drilling that hole or you'll have much bigger problems. Those bolt holes are probably and inch deep at least.

First, your drill bit is too close to the diameter of the bolt. It's tough to drill that straight without a drill press, so scale down the bit. If I drill I always start small and try to get a nice straight pilot hole without wandering off the bolt.

You should also remove the pipe so you can get at the working area properly.

[crag antler]

Don't beat yourself up too much. I broke 2 exhaust studs on my XL600 while just trying to remove the pipes to paint them
I didn't have enough meat to grab onto and all the tricks I tried did not budge them. I ended up taking the head off and going to a machine shop.
4 studs later, I was set. 2 broken and removed the 2 "good.I didn't want to go thru that again. Only about $40 and no problems since.

[lurch12_2000]

If you drilled 3/8" into the bolt and are hitting aluminum your not bottoming out, you're drifting off center. Stop drilling that hole or you'll have much bigger problems. Those bolt holes are probably and inch deep at least.

First, your drill bit is too close to the diameter of the bolt. It's tough to drill that straight without a drill press, so scale down the bit. If I drill I always start small and try to get a nice straight pilot hole without wandering off the bolt.

You should also remove the pipe so you can get at the working area properly.

Well, I'll accept the fact that 3/8" is not very deep, hence I was waiting for an answer to the original bolt size length question, but I would be suprised if they were an inch or more deep into the head?...but anyway, the holes are straight in. I may have mistaken the bottom looking like different metal color (alum vs steel), but rather than drilling too deep, I stopped. And yes, I used a smaller drill bit to start (not shown) for the initial pilot hole.
I tried a left handed drill bit with no success (and never have had any luck with them). Not to say they haven't worked for others.
You're also assuming that I can remove the other bolts without snapping them too, to remove the pipes for a larger working area.

...update...the bike is back on the road and the new self tapping bolts are holding. Without locating a "bottoming" tap I couldn't be sure to get enough thread cuts for the new bolts to screw into. The self tapping bolts are slightly tapered with threads right to the tip to basically match the hole contour from the drill. Used plenty of WD-40 and slowly threaded each bolt down evenly. I also used lock washers to maintain spring pressure on the flange as opposed to torquing them down too much.
So the points are:
Don't mess with 30 yr old exhaust bolts until winter project time unless you really have to.
I'll let you know how the self tapping bolts hold up on the next 1k miles.
You may be able to do this fix without head removal from the bike, if you're careful. But I certainly wouldn't want to push my luck beyond 2 bolts.
If you fail, then you'll have to remove the head and probably get the machine shop to do it anyway. Then you can really find out how many 30 year exhaust bolts you can bust... and maybe valve cover and head bolts too while removing the head.

[1948man]

For future reference, I sprayed PB Blaster on on my exhaust bolts every day or so for a week while I was waiting for my new exhaust to arrive. They came out easy. Might not work in every case.

[reddirtrider]

I just measured the depth of the exhaust bolts on an 1100 head I have lying around. They are 24 mm deep - that's about 15/16th of an inch.

[errorcauser]

I still have the tape on my drill bit that I used, and from the tip of the bit to the tape (using my caliper) I get 18MM.

Welding a nut to the tip of my broken bolt, didn't work. Using left handed bits, didn't work. I soaked them twice daily with PB blaster for about a week or longer before attempting to remove them, one still broke off.



18MM, 1980 GS850GL.

[lurch12_2000]

I just measured the depth of the exhaust bolts on an 1100 head I have lying around. They are 24 mm deep - that's about 15/16th of an inch.

Thanks for checking on that. The 1100G might have more meat on the head and bolts go deeper.

Errorcauser...that would be 3/4" on the 850G or just about 3/8" (9mm or less?) more I could've drilled out maybe...maybe 16mm not 18mm? since your caliper is not quite touching the end of the drill bit.

1948man....BTW, I did spray it 3 times over the previous 3 days before making my attempt.

I just don't think you can fight 30 yrs of never been touched?

[errorcauser]

Thanks for checking on that. The 1100G might have more meat on the head and bolts go deeper.

Errorcauser...that would be 3/4" on the 850G or just about 3/8" (9mm or less?) more I could've drilled out maybe...maybe 16mm not 18mm? since your caliper is not quite touching the end of the drill bit.

1948man....BTW, I did spray it 3 times over the previous 3 days before making my attempt.

I just don't think you can fight 30 yrs of never been touched?

It's exactly 18MM. I think things shifted a bit when I laid them down to take the picture, and as well the camera angle makes it look odd, I don't know.

I also put tape around the tap (just incase) and I noticed thread prints up on the tape. So, I measured from the tip of the tap to where the thread prints on the tape stopped...I got 24MM just as reddirtrider said.

So, maybe the hole is 24MM deep, and the bolt actually goes into the hole a depth of 18MM?

I do know the stainless bolts that I bought are the correct length and thread pitch. They'll thread into either hole, and the length matches the originals perfectly.



Drill bit size = 17/64 (The recommend final size [printed on the tap package], after working my way up starting with smaller bit's)

Tap size = 8MM -1.25

[duaneage]

I attached a socket to my impact driver and used that to remove the exhaust bolts. I've been very successful. I changed the bolts out for studs on my 650 with a set from Napa for 13 dollars. They look great and work better, the nuts that come with the studs are friction type that don't loosen up.

I've never seen any trick work on broken studs. Wax, PB blaster, heat, easy outs(oxymoron for sure) or welding it all seems to fail. When there is an inch of rusted bolt in the head you can't twist it out with only an 8mm cross section of bolt. The heat seems to soften the bolts up too, at least they are easy to drill out.

If you do drill out too far you can tap to a larger stud but you risk weakening the mount. One of the holes is blind, one goes through.

[Nessism]

I experimented with different header bolt removal techniques on a parts bike with a trashed engine. On the stuborn bolts I hit them with PB blaster several times over the course of a couple of days and then used heat on the bolt. It's important to go easy and don't torque past a certain point or the bolt will snap off. Use heat and try turning the bolt both ways. Once you get the bolt to move a little you still need to go easy. Hit it with more PBB and more heat. Turn it both ways back and forth until it wants to start turning without too much torque. It takes time and a sensitive touch but can be done most of the time.

[TheCafeKid]

I experimented with different header bolt removal techniques on a parts bike with a trashed engine. On the stuborn bolts I hit them with PB blaster several times over the course of a couple of days and then used heat on the bolt. It's important to go easy and don't torque past a certain point or the bolt will snap off. Use heat and try turning the bolt both ways. Once you get the bolt to move a little you still need to go easy. Hit it with more PBB and more heat. Turn it both ways back and forth until it wants to start turning without too much torque. It takes time and a sensitive touch but can be done most of the time.

Verry good.

Couple things I wanted to add, just for everyone that might end up with the same problem, or similar.

One: if its not snapped flush, another technique is to weld a nut onto the remaining bolt, and then extract using that. I will have to do this on my 1000G thanks to my little brother's hamfisted wrenching ability.

Two: a neat little trick Cole actually taught me, some of you may already know. Lapping compound. If you can actually START moving the offending bolt, coat with some lapping compound and work back and forth as Ed says. The compound will not only clean up the rust, but will clean up the thread leads themselves, making for NICE CLEAN threads to put new bolts into when you finally get it out. We actually had to do this on a rotor/crank end nut to clean all the ORIGINAL loc-tite from it. Wouldnt go on very far at first, but after the lapping treatment, it went on clean as a whistle. Neat and handy lil lesson...thanks Cole!

[crag antler]

...update... Then you can really find out how many 30 year exhaust bolts you can bust... and maybe valve cover and head bolts too while removing the head.

Don't ask me, too damn many

For future reference, I sprayed PB Blaster on on my exhaust bolts every day or so for a week while I was waiting for my new exhaust to arrive. They came out easy. Might not work in every case.

I tried PB Blaster for almost a week before my troubles.Could have been stubborn 26 yo bolts

I experimented with different header bolt removal techniques on a parts bike with a trashed engine. On the stuborn bolts I hit them with PB blaster several times over the course of a couple of days and then used heat on the bolt. It's important to go easy and don't torque past a certain point or the bolt will snap off. Use heat and try turning the bolt both ways. Once you get the bolt to move a little you still need to go easy. Hit it with more PBB and more heat. Turn it both ways back and forth until it wants to start turning without too much torque. It takes time and a sensitive touch but can be done most of the time.

Just another case probably of my stubborn bolts. Heat didn't help.