Can be caused by being loose as well as over-tightened.

Hopefully some penetrating oil and a screw extractor will get the job done.

 

Take care if you attempt to get that out yourself. I've had no success in recent years with extractors and if the darned thing breaks, leaving the tip embedded, you have a bigger problem. Consider getting an indy or even a dealer to remove it.

 

this^
or take it to a machine shop if they are unwilling to help

 

Whatever you do, don't put an easy-out or any other kind of an extractor into that stud. You have about a 99.999% chance of breaking it off and a .001% chance of extracting it successfully. Those studs are an interference fit thread on that end, they're designed to bind up in there, and they do a mighty fine job.

There's a special drill fixture tool for making this repair. Don't even attempt the repair without that tool. You're likely to make things much worse.

 

On the bright side this is the easier of the two exhaust ports to work with!

To do this properly you need to drill the bolt down to the bottom starting really small and working your way up in size, take it slow and use oil. This technique allows the bolts pressure to relax and come out easier. Then spay it with PB blast and let sit for a few hours/overnight. Grab your Quality extractor (No cheap stuff here - you will regret it) and have at it, the bolt will come right out.

 

if heads are aluminum , you could try and mig weld a nut to it and back it out? as this will heat it at the same time. I do it weekly at the jeep dealer on exhaust manifolds or any broken bolt in aluminum. just a thought

 

buy a left hand drill bit. usually works and will not break off in the stud.

 

This is nothing new. It's been going on for as long as Harleys have had exhaust studs. There have been numerous discussions about it on this board and on others for a long, long time. Tons and tons of people have had this issue and have learned the hard way that extractors almost never work in this situation. And then they've got a broken off extractor stuck in the bolt and at that point the repair gets a whole lot more expensive. The head has to come off and go to a machine shop that's willing to sacrifice multiple expensive carbide end mills to get it out, because that's what it takes to cut out the broken extractor. Carbide is the only thing that will cut the hard steel of the extractor, and carbide end mills aren't cheap and usually more than one of them gets destroyed in the process. I won't mention my shop, but we do this repair all the time and it's not cheap.

Solvents and lubricants are ineffective at releasing the stud. That's because the binding is not so much due to galvanic corrosion as the fact that the stud has an interference fit thread. You're talking about a thread design that's DESIGNED to bind up in there. The stud binds up the day it's screwed in there. No amount of solvent or lubrication is going to change that fact. They use this special interference fit thread so that you can remove the nuts without the stud coming with it.

Drilling the stud without a drill guide is iffy at best. The drill bit will wander and go into the aluminum. It's very difficult to drill straight down the center of the stud without a drill guide.

The right way to do this is with this drill guide, or one of the many copies of it on the market:



You bolt this on using the good stud. You then drill the broken stud using the supplied 1/4" drill bit. Works slick as snot. The stud is 5/16" diameter and the guide works so well that many times I've drilled this 1/4" hole with the drill guide, right through the center of the stud, and left an easily-removed shell of the old stud, without damaging the aluminum threads at all. At that point you just screw in a new stud and you're done. Good luck doing that without the drill guide.

I recommend the factory stud (16715-83) , because none of the aftermarket ones I've ever found have the interference fit thread. So if you go with an aftermarket stud, you may end up cussing at it some day when you go to remove the exhaust and the stud comes out. When you screw in the factory stud, you'll notice that you're fighting it the whole way. That's the way it's supposed to be.

There are a handful of different brands for this tool. It's not free, but it's a whole lot easier and less expensive than pulling the head, taking it to a machine shop, having them remove a broken extractor and repair the threads, and putting the head back on. Bite the bullet and save yourself a lot of grief and money and do it right the first time. There are many, many people who tried the extractor method and later wished they had just got the drill fixture.

Now I'm not going to say that nobody has ever been successful with an extractor. But for every person who I've seen report success with an extractor on these boards, I've seen 100 who reported breaking it off. So if you go that route, don't say you weren't warned.

 

That should be a sticky thread of it's own at the top of the forum. Thanks aswracing.