Broken Exhuast Stud

[He Man]

Alright, im bombing you guys with questions so heres another one!

I broke the exhaust studs on my 1100 motor. I managed to get 2 out with a welded nut, but the other two keeps snapping the weld repeately. Tips and thoughts? Am I going to have to painfully drill this out?

[ducpainter]

Try a little heat. If that doesn't work you'll probably need to drill.

[Howie]

If you have to drill it out use a left hand drill bit  https://www.homedepot.com/p/Drill-America-18-High-Speed-Steel-Left-Hand-Drill-Bit-12-Pack-DWDLH18P12/310590852

The bolt will sometimes come out just from the heat and vibration from the drilling.

[He Man]

While ive not put an actual torch to it, ive welded a nut to it which has gotten it red hot (at the head atleast).

Ive not tried LH drill bits before but the LH drill bit before but I'll give that a go. I did order individual colbolt bits in M3 and M4 and M6, and an extractor set too.

This has got to be the most stuck bolt ive ever removed in my life! The only worst one i remember is a stuck bolt on a saab turbo manifold.

[ducpainter]

I'd heat the head with a torch, spray the area with some penetrant like PB B;aster, give the stud a whack with a hammer, then weld the nut on. Heat the head back up before trying to unscrew it.

If the stud won't come out by welding a nut on it, I doubt you'll have much luck with an extractor/ez out.

The two pieces have welded themselves together due to the dissimilar metals. Good luck.

[He Man]

I understand the dissimilar metals and how they can weld thesmelves together, but Mild steel and Aluminum arent that far apart from each other unlike stainless and aluminum. That basically means stainless is terrrible replacement. what about titanium? I really dont want to drill out titanium nor stainless so should i just go back to OEM mild steel?

Granted the bike sat outdoors for 4 years so this wouldnt have happened if it was garage kept atleast in the winter.

[ducpainter]

I'd disagree regarding the mild steel and aluminum...regardless...they're stuck.

When you go to install a new stud, coat it with never seize.

[Orange16]

Heat.  Soak with favoured penetrant.  Whack with hammer.  Let cool.  Repeat.  You could try the candle / crayon methods people use for oil gallery plugs on cast iron blocks.  Not sure if it works on aluminum. 

As ducpainter says, it's stuck.  Drilling will be a complete thread removal and replacement scenario if you don't get it unstuck.

[He Man]

I went back to try nad get these bolts out, i used a ton of heat, but to no avail so I purchased several cobolt drill bits.

I dont understand how hard this bolt is, but after going at the bolt for about 10 minutes, i made a tiny dimple. Im using Tap cutting fluid, 135 split point cobolt bits. Its almost as though this bolt is hardened steel. What gives? has anyone experienced a bolt thats extremely hard to drill?

[koko64]

Yes, early 900 engine studs. Snapped flush with the case on an M900. It blunted cobalt bits. In the end it was a die grinder and major thread repairs. If your city has a thread doctor who does this day in day out, I would call them.

[He Man]

I bought a 10 pack of cobolt bits, its just wrecking the bits. Im litterally at awe over how hard the steel is. I dont even know what tool i could use to hold a die that could carve this bolt out. Its an M8, i mean at the cost of that, i might as well just swap heads.

Lets say I do take the head off to get it on a bench, is there just a metal head gasket that gets replaced? I just hope I dont snap my head bolts in that case! It would be easier to just cut the aluminum and tig it back up!

[koko64]

The later head studs were better.

Yeah it's a tough job for sure. You're trying all the right things and unlucky.

Took me a couple of hours each night over a week to win that battle. I should have just called the guy.

[He Man]

A couple hours a night sure sounds right. Im looking for a guy online right now but im also concerned that people will say "yea i can do it" but end up trashing my heads. Which for the record,  I am absolutely capable of doing myself.

[He Man]

i just took a night time trip to home depot to pickup milwaukee multimaterial shockwave tips, its basically a carbide tip. smoke the bolt like butter, but the extractor still cant get it out so i plan on going up to the next size and trying to break the thread plane then get some pb plaster in there and let it sit everyday day for a few days.

[koko64]

Let us know how it goes.