Broken exhaust studs

In order to install a GSXR600 rear shock I took off my exhaust system. The front studs sheared off instead of unscrewing. I've tackled the right hand side one with a stud extractor to no avail and now have a partially drilled out stud with a small projection that I can get grips onto but which is going to break off before it moves the rest of the stuck stud, I think. What do you suggest? Could I enlarge the hole I have drilled in the right hand stud and tap a new thread into it? Do I need a helicoil? Could I reasonably do either of these myself or should I get it to a specialist? If so, can they do the job on the bike or should I take the head off?

So far as I can tell without riding the bike, the suspension up-grade went very smoothly!



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Same thing happened to me when I re-greased the swingarm and had to take the exhaust off.

I heated up the stud and then frooze it with a can of halfords spay (I think it was called 'shock and unlock'). Then very very carefully I got it mooving with a pipe wrench.

Then bought new allan bolts and used a lot of copper grease (and put on new exhaust fittings on the downpipe so I wouldn't have to take the manifolds off again!

Sounds worth a try. Thanks

[yorkie_chris]

Don't use allen bolts, use stainless studs.

Yes you can enlarge the hole and re-tap it. A good first move is to soak the area thoroughly in penetrant oil for a good long while, then to get hold of some left handed drillbits.

[DarrenSV650S]

If you are going to drill and tap it. Try the original size first. That should clear out the broken stud and leave you with the original thread

The Shock Unlock didn't work and they've been drenched with WD40. I've drilled one stud down to the blind end so it's had WD40 from both ends. I've heated them and frozen them. I've used left hand thread extractor bits. I bought a set of stud extractors that slip over the stud and grip as you turn but the broken end was too short.

Originally Posted by DarrenSV650S

If you are going to drill and tap it. Try the original size first. That should clear out the broken stud and leave you with the original thread

I've thought about this one but I've decided it would only work if I was able to start the tap in the line of the original thread. The chances of doing this are poor and if I get it wrong I'll be cutting out at least part of the original thread leaving a very much weaker fixing. I can imagine having spent ages on my back carefully tapping it out and then stripping the weakened thread as I torgue the new studs back up.

I'm tending strongly to the helicoil. Need to think of a way to fix the line of the drill bit so that the new studs are in the right position and square. I think it will wander if I just hold the drill and guess, even with a centre punch on the stud I haven't drilled yet.

I like the stainless studs suggestion - if I ever get that far!

Thanks again, all.

[Viney]

If you have one out, then bolt the clamp in place, then drill the centre out through the other hole. Im not going to tempt fate as i have to take my system off in a couple of weeks for the MOT

[DarrenSV650S]

When it happened to me it was just the one stud. So a metal block was used as a guide to keep the drill straight. It was bolted to the engine using the other stud, and it had various different sizes of holes in it, all the same distance from the good thread to the broken one. The first smallest drill bit was used then the metal block was spun around to the next larger size etc etc

This was done until most of the broken stud was removed, then the original tap size was used to clear out the remaining metal.

[maviczap]

Originally Posted by yorkie_chris

Don't use allen bolts, use stainless studs.

Yes you can enlarge the hole and re-tap it. A good first move is to soak the area thoroughly in penetrant oil for a good long while, then to get hold of some left handed drillbits.

Wish I could help, but my studs came out ok when I replaced my headers.

Whats the thinking behind using stainless studs, rather than stainless allen bolts yorkie chris? If studs are better, then I'll swap over in the winter.

I replaced the OEM studs with stainless allen bolts on the front, I didn't have to do the rears

Originally Posted by DarrenSV650S

When it happened to me it was just the one stud. So a metal block was used as a guide to keep the drill straight. It was bolted to the engine using the other stud, and it had various different sizes of holes in it, all the same distance from the good thread to the broken one. The first smallest drill bit was used then the metal block was spun around to the next larger size etc etc

This was done until most of the broken stud was removed, then the original tap size was used to clear out the remaining metal.

If only! I have one sheared off flush and the other protruding. I think I will have to make something up like you describe and find a way to clamp it to the head. I can use the one that projects to locate it and then, when I've fixed one I can use that screw to deal with the other. I had hoped to use the original clamping plate as Viney suggets but it won't come off the down pipe as there are collars at each end.

Thanks again for your interest.