Exhaust header studs

[James England]

I've been emailing with a fellow XSive. He's mentioned exhaust header studs. I believe the engine is out of the frame. So, here's a question, with a poll!

Basically, what do others think about removing the old header studs? The threads are apparently in good condition but, as far as I know, the stud metal can get brittle with all those hot cold cycles over the decades.

I just replaced my XJR studs after 7,000 miles and 9 years. Seven came out easy but the 8th, right behind one of the frame cradle tubes, notorious for being a swine to get out....didn't come out. It sheared. I ended up trying everything known to man to get it out and finally used a small stick welder to weld a bolt onto the stump, having passed the point of no return by trashing the threads with an Irwin wrench. It finally allowed the stud to be removed but, even then, I took 30 minutes of judicious tightening/untightening squirting Plus Gas into the stud, backing it out a bit more etc... I've known threads strip even when a bolt is moving because it jams up again unless done gradually.

Leaving old studs in could mean a snapped stud on a trip, as has been mentioned on this forum, but getting them out can be nerve-wracking and a pain. But, having done all my XJR ones, despite the Stud from Hell (no, not a blue movie), I'm pleased I persevered.

What does everyone think?

[BA80]

I'm of the mind that "If it ain't broke don't fix it".

[crazy steve]

I'm a firm believer in the 'if it ain't broke, don't fix it' camp. The amount of work I've created for myself in the past when 'fixing' stuff 'just because' finally cured me of that.....

Not to say that replacing marginal parts is a bad thing, but make sure it really needs it. Most problems with these is due to improper installation of the nuts; some anti-seize will work wonders, as will using the right torque specs. If you still have a leak, you need new gaskets, don't keep cranking the nuts tighter...

For anti-seize, use PeptoBismol (yes, really!) and just 'paint' some on the studs. The magnesium aluminum silicate in it will remain after the liquids boil out and help prevent seizing.

The other thing I see is guys replacing neck/swingarm bearings if they're even a bit discolored, another waste of time/money IMO. If they're actually pitted or have been overtightened enough to mash the rollers out of round or damaged in some other way, yeah those need replacing. But if they spin smoothly after cleaning/greasing, they'll be fine. Sure, if those were wheel bearings you'd replace them, but the range of motion on these is under 90 degrees (when riding it's under 15 degrees) and will literally never wear out if grease is present.

[James England]

I'm of the mind that "If it ain't broke don't fix it".

Sure for most things but preventative medicine can be advisable on some things...you know, like a cam chain replacement, or waiting for brake pads to go metal to metal or whatever. I read a thread on here about someone on a long trip whose header stud just snapped, presumably due to age and just forgetting about them. For some things, I believe 'fix it before it breaks'....but I'm not sure where the header stud thing belongs! I'm certainly glad I did mine...now that they are done..but, at the time, I was questioning whether I really needed to have done it, as per "Ain't broke, don't fix it' philosophy, especially when it came to getting the welder out.

I suppose now, the studs are 'not broke, won't break, won't need fixing'. Reassuring but a definite ordeal with that last stud....

[D0wn5h1ft]

It'll come back to bite you if you don't take them out. It's not hard and you can get nice OEM ones with the nice anodized coating from your yammy dealer. Best decision I've made. Once you snap off a stud in your head you'll never pass up the opportunity to do it again.

[IanDMacDonald]

Here's my thing: I have horrible luck. Sure, it may be from ignorance, but's that's symantics. I'm joining the camp above. Yes, I am doing some mods to my bike. However, the mods are within the grasp of my mechanical knowledge. I enjoy learning tips & tricks, and I'm a firm believer in preventative maintenance. But, when that "preventative" maintenance could possibly lead to more headache because I broke a stud just because it was "ugly", I'd rather buy a can of paint and touch them-up over removing them.

[James England]

But, when that "preventative" maintenance could possibly lead to more headache because I broke a stud just because it was "ugly", I'd rather buy a can of paint and touch them-up over removing them.

i don't think ugliness is the issue though, especially as most of the stud is hidden. For me, it's the functionality of the stud. It's mild steel, decades old, been subjected to thousands of heat and cooling cycles, possibly corroded and I believe the tensile strength of the stud therefore deteriorates, even if the threads look OK.
Out of interest, I destroyed the 7 old studs from my XJR by holding them in a vice and bending them 90 degrees back and forth. The metal was brittle and broke usually on first bend. I did the same on a spare mild steel new stud...it was much harder to bend and took 3 or 4 bends before metal fatigue set in and it snapped. Anecdotally, this suggested that a 9 year stud gone through only 7,000 miles was much weaker than a new one. I'd have thought several decades and many more miles would render the stud even weaker.

I wonder how many XSives have had a stud break in use????

[crazy steve]

...Out of interest, I destroyed the 7 old studs from my XJR by holding them in a vice and bending them 90 degrees back and forth. The metal was brittle and broke usually on first bend. I did the same on a spare mild steel new stud...it was much harder to bend and took 3 or 4 bends before metal fatigue set in and it snapped. Anecdotally, this suggested that a 9 year stud gone through only 7,000 miles was much weaker than a new one. I'd have thought several decades and many more miles would render the stud even weaker.

I wonder how many XSives have had a stud break in use????

I doubt if that is an accurate test. If the OEM studs are grade eight, those don't bend, they break. I know from personal experience that when replacing bolts on exhaust systems, grade eight bolts hold up much better over the long haul.

I've never had exhaust bolts/studs break while in use, only when installing/removing them...

[clcorbin]

The heat cycles won't do squat to the mild steel. The temperature that stud sees in the front of the cylinder is nothing compared to temperature it is held at for heat treating and tempering. You are WAY below the metal transition lines.

Corrosion, on the other hand, is a whole different story. Especially for you guys that live near the ocean or in areas with lots and lot of moisture in the air (I THINK it is called humidity, but I live in the desert, so I'm not sure). The oxidation and pitting leads to stress concentrations that can lead to failure. But usually, that failure is when you try to remove the corroded stud from the cylinder and discover that the aluminum and steel have REALLY come to like each other. Then that little pit of corrosion causes a shear failure as you try to break it free.

I guess they call it "break it free" for a reason...

[DGXSER]

I can about guarantee I have seen and worked on some of the crustiest exhaust systems in existence on the bikes I tend to buy. Her en the land of humidity and long periods of rain and buying bikes that lived outside without being ran (no heat to dry things out) for years. And I have yet to have an exhaust stud snap on any of the bikes I have worked on. Now, for some reason, the studs in car exhaust do tend to snap pretty easily in my experience. I have yet to get an exhaust manifold off without snapping at least one.

So I think this is making a huge figgin mountain out of an ant hill, small little f'n ants at that. I agree with CClorbin, you are no where near the heat levels to deform or alter the crystal structure of the steel with the temps of these heads. Now work hardening and deformation is an entirely different story. And I have yet to bend a stud removing the nut. The worst thing ever happens on one of these bikes is the stud screws out of the head instead of the nut coming off. In which case I clean up the stud and the nut and reinstall it back in the head with the exhaust.

[bikerphil]

I've never broke any either. <knock>

[James England]

http://www.xs11.com/forum/showthread...ht=Header+stud

He didn't knock.......

[James England]

I've never had exhaust bolts/studs break while in use, only when installing/removing them...

I've only read of one person that it happened to..either here or on an XJR forum...he heard the usual sound from a loose header and found a stud had sheared......

By the sound of it, corrosion is the thing, so if the threads are OK, then nobody has a problem, right.?

Mind you, I'm still glad I replaced mine. I used titanium studs and nuts.

[MaximPhil]

Hi James,
I may be that person. Since owning Addie the exhasut has been on and off about 6 times. The first failure was during installation one snapped off with enough left over that welding a nut on became the solution after numerous attempts with other methods. Then one came out of the head and we replaced it witha bolt. The inservice failure was after these two about 500 miles down the road. I have yet to repair the stud broken below the surface(too damn cold in the garage)
Mussings: During all the installations have the studs been over torqued?
Do studs age with heat cycles and therefore more prone to break.

would I be advised to change the ,now suspect, old studs for new across all 8?
Phil
PS replacement after market studs i ordered are the wrong size.

[James England]

Hi James,
I may be that person. Since owning Addie the exhasut has been on and off about 6 times. The first failure was during installation one snapped off with enough left over that welding a nut on became the solution after numerous attempts with other methods. Then one came out of the head and we replaced it witha bolt. The inservice failure was after these two about 500 miles down the road. I have yet to repair the stud broken below the surface(too damn cold in the garage)
Mussings: During all the installations have the studs been over torqued?
Do studs age with heat cycles and therefore more prone to break.

would I be advised to change the ,now suspect, old studs for new across all 8?
Phil
PS replacement after market studs i ordered are the wrong size.

According to some responses on here, the heat cycling doesn't get hot enough to affect the steel structure. They do corrode though. Personally, I don't imagine that all that heat and cooling over 30 years leaves the studs the same as they left the factory....
Your studs sound a bit ropey with a bolt here, a sheared one there.....might be time to bite the bullet!