Exhaust Stud broke off

So I've been riding for a few days since replacing the starter. Now I've broken 2 exhaust studs off on the same exhaust.... They snapped off about 1mm in. I've been researching it a bit and am a little nervous.. Does this bolt go all the way through the engine? Any tips on how to replace it?

 

Also is this the part number:
90116-10330-00

 

it doesnt go all the way through. You could drill it out and tap it for a bigger stud or helicoil it, or you could try and use an EZ-out. Or you could use a welder and build material up and weld a nut to it so you can turn it out. But I have to say after seeing lots of these, What you really should be doing is bringing the head to a machine shop with a tap dis-integrator.

sorry, wish I could give you better news.

 

for future reference.... get yourself some kroil.....

now, your best bet is a machine shop....

 

The first thing to do is abide by the Number-1 Rule for being in a tight spot fixing-up an old motorcycle.

Rule No. 1 "Don't make your bad situation worse!"

The broken remnants need to be removed.
If the broken Studs are on #1 or #4, ... there is a chance the work can be done "In situ" ...
If the inboard Studs are involved, ... your better-off pulling the Head and outsourcing the job to well-qualified machinists.

One resource that should be investigated is the Machine Shop Department Head at a local or nearby Technical High School or College.

If you decide to approach a Technical School for help, ...
• Bring well-lighted and in-focus photographs.
• Have with you a Genuine Yamaha Workshop Manual for your bike.
• Suggest you'll make a donation to the "Shop Expendables Fund" for their help rescuing you from the predicament.

 

Send an email to XJ4EVER to order new ones. You won't need a part number for that route. Use a never seize compound when fitting new ones and get a torque wrench..

See also

http://www.xjbikes.com/Forums/viewtopic ... e+wax.html

 

I'll never learn this.....

 

It's never about learning how to do it, it's just developing the foresight to actually pull it off.

 

New to the Forum.
Just purchased a 1982 XJ750 Maxium that I started restoring.
I have the opposite problem. Looks like previous owner did a helicoil fix i want to fill and weld and re-drill and tap. What is the specific material the head is made from? I have searched for ever and found nothing. Any help is much appreciated.

 

That Helicoil is likely better/stronger than the original material, leave it in.

 

all engine casings , barrels and head are made from alluminium alloy.
stu

 

The Helicoil has stripped or worked itself out, I'm just left with a bigger hole filled with RTV and stud from previous owner... he said he wasn't a mechanic, that's an understatment!

He also pulled the baffles and put pod intakes on and wondered why it ran like crap! Not to mention the horrible exhaust leak on #4 (because the bad stud).

I will be re-jetting the carbs this weekend. Just ordered 130 mains from JetsRus.

Looks like I will be firing up the old TIG welder with some filler rod.

 

What is the thread description for a tap if he did want it re tapped ? (I have a similar problem on No 1 of an 84 XJ900). I have the stud all out, but the thread is damaged.

 

What is the thread description for a tap if he did want it re tapped ? (I have a similar problem on No 1 of an 84 XJ900). I have the stud all out, but the thread is damaged.

 

I'll look up the thread size tomorrow, but I'll tell you right now to not use a tap. Taps are for cutting new threads. You want to get a thread chase (does not cut threads, but reforms what is there), if there is enough material to salvage a good thread from. If the threads are very far gone the best method would be using an insert.

 

thread chasers are for male threads. this might be what your thinking of
http://www.mcmaster.com/#thread-forming-taps/=sewyij
but just like a tap, if it breaks your in a world of DoDo
the studs in 750's are 6 X 1 threads

 

Thanks mate.

Polock has linked to what I'm after with the numbers (and keywords) I needed.

I have 18 mm length of 4.5 mm min diam open hole and with 5 mm of 5 mm diam hole at the front end, (gauged with drill bits) so 13 mm hopefully enough meat to work with for he right shaped M6 cold forming tool. I still have the option of an M6 helicoil if that won't hold, but it's a new one piece header system so it's well supported by the other exhaust studs and I just need a bit of bite on the seal ring; it's offsider is good....

Cheers for that info Polock. Pretty sure the 900s would be same as 750s.

 

if you use a tap like that , use motor oil on it, not cutting oil.
remember cast AL is brittle so go easy

 

Thread chases are avalible for both internal and external threads. The name decsribes how the tool works.

 

Just a word to say thanks. Got hold of a M6 thread former, worked well, so now have a new stud all the way in....first time since I've had the old girl that this has been so!
The new 4 into 1 system has been painted and will go on when I get home from work in a couple of weeks. The new system is much better than the old one, headers are all one unit, rather than the individual headers on the old system which was a generic job I think, rather than specifically designed for an XJ900 like this new one (from the US when the Aussie dollar was high!).
Soon I'll be able to roll the bike out of the lounge room, which, needless to say will make my missus much happy

 

This is interesting - I never knew 'cleaning' a thread with a regular tap or die
was a no- no. Now looking to get myself a tap former/chaser for M6 x1. Is it the case that 'fluteless' taps are all formers ?

Cheers.

 

I'm no expert, but that would seem to be the gist of it. I guess where you have enough thread to give the tool some 'grip' it will want to follow that established path rather than cut a new one.

 

The exhaust studs are pretty much the same for all the xj's. I have a whole box full of them off of various bikes I've parted out. Regardless of part #, they're all the same, other than some being slightly different lengths, but THAT doesn't make a difference---thread it in til it stops, torque it, put the collar on, and put the nut on......which BTW, the nuts are all the same, too-----yup, the box has has a lot of those in it too..........

For the fellow that is contemplating filling the hole----- yeah, he WOULD need a tap. If he's FILLING the hole, he'll have to drill it and then re-tap to the correct size and thread.

If the hole damage is big enough......how about 'propping the stud in place and building the aluminum weld right around it! THEN it'll never come out....just be aware of that in the future......lol

BTW, there have been posts in the past about some shops that can now remove studs like that with a procedure that destroys the stud without damaging the aluminum. It's done sonically, I think, but I can't for the life of me find the link or think of the term. It's kind of an interferometry type of thing-----


dave

 

EDM. Electrical Discharge Machining. The fastener is eaten away by a small, high-voltage arc.

 

The flute in a tap is there to provide a path for swarf to be removed without having to back the tap all of the way out, but it also makes for a weaker tap.
Fluteless taps are not thread reformers.
No matter what, a tap is not a chase, and it is not a thread reformer.
Taps have sharp cutting edges that remove material. They have one job, cutting threads into a new hole. Using one to clean up, or reform threads is a dicy procedure because you'll be removing material from an already weakened/damaged thread.

 

Not sure if you got the remaining stud out of the block. If not, don't try and drill and tap it out. Instead, take it to a welder and have them weld a welding stick to it and back it out that way. Then, you could use a heli-coil if the threads are damaged. Although, it's best to keep the threads undamaged and get a new stud.

Good luck. I've been there before and it's not a lot of fun.

 

a little read on taps and chasers
http://www.practicalmachinist.com/vb/ge ... ap-237679/

 

Thank you - I am now fully informed. Confused as hell, but fully informed..