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Look around the stud hole, is extra metal for the stud hole there?
What about outside area of the stud hole??
Coolant in the head and around valves.
How far is this stud hole from the exhaust valve?
 

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Honestly, if you haven't had any issues to this point I'd just leave it. If you TIG it, you'll have a machining job in front of you. I'd bet it was way over tightened at some point. As I recall, you're looking at 100lb/in tq, on the exhaust nuts. It's not a lot of torque, and once the pipe is installed, it isn't going anywhere. If the pipe is properly mounted, there really isn't a lot of stress on the flange.

Of course if you wanted to fix it properly, you'll need to grind the crack out and fill, and machine back to form. If you TIG in small increments, I don't think you'll even have to unmount the head. Just leave it bolted down to the jug, and the jug on the crankcase. Just do the job in stages, allowing some cooling between to allow the weld to heat soak. Personally I think it's a lot of unnecessary effort, unless you already have a leak.

Use OEM crush gaskets and you'll not have to exceed the torque spec.
 

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You know dad suggested to me drilling a hole at the end of the crack and it isnt a terrible idea. It reduces the stress concentration in that area.

I talked to a buddy and he told me that I don't have to remove the head to preheat it... that I can run the engine for a while and then re-weld it while still warmed up and that sounds like an incredible idea to me!

I have another friend that suggested that I "pin" it... not yet sure what that means but he is a bada** about all things engine related so I'm excited to hear his feedback.

Looks like I got some viable options.

I will post a how-to of what I decide to do, and a follow-up to say if its working or not to help anyone in the future.
 

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Unless anyone else has any more input... I saw Hans and Feet you were asking for dimensions to the valve. Are you considering that it would be too close to the valve seats for welding?
 

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No!
I believe the port is large and stud holes are away from critical items.
My only reference is my 1300.
Inspect and analyze.
If you do any welding with head in place disconnect the ECM connectors.
 

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You know dad suggested to me drilling a hole at the end of the crack and it isnt a terrible idea. It reduces the stress concentration in that area.

I talked to a buddy and he told me that I don't have to remove the head to preheat it... that I can run the engine for a while and then re-weld it while still warmed up and that sounds like an incredible idea to me!

I have another friend that suggested that I "pin" it... not yet sure what that means but he is a bada** about all things engine related so I'm excited to hear his feedback.

Looks like I got some viable options.

I will post a how-to of what I decide to do, and a follow-up to say if its working or not to help anyone in the future.
In re: to the 'pinning' idea. Back in the early 70's I had a Z28 that would redline at 7K. I bought it used, and had problems with the rocker studs pulling out of the heads due to being over-revved and stressing the stud bosses. Newer heads came with threaded stud bosses, but as a fix for the old style, it was a fairly easy fix to drill through the stud boss and the stud, and put a spring pin in the drilled hole perpendicular to the stud.
 

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In re: to the 'pinning' idea. Back in the early 70's I had a Z28 that would redline at 7K. I bought it used, and had problems with the rocker studs pulling out of the heads due to being over-revved and stressing the stud bosses. Newer heads came with threaded stud bosses, but as a fix for the old style, it was a fairly easy fix to drill through the stud boss and the stud, and put a spring pin in the drilled hole perpendicular to the stud.
I had 1970 2.02 heads with press in studs. A year before the angled spark plugs.
I bought the threaded studs and tapped the stud bosses.
I have that on my 283 resting in the basement.
The power pack heads were better for the 283.
 

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I also have an exhaust stud hole crack. My concern is not that the stud will hold torque. My concern is that the crack will propagate until it reaches a water jacket or oil passage and ruin the engine.

Does anybody have some experience with this issue? Will I have some major problems down the road?

I just spent more money than the bike was worth fixing all kinds of other problems, I would hate to sell her.
The threads could use a re-tap, but would still hold a stud if they're not like that all the way to the bottom.

Dremel the crack with a small diamond bit and tig it if you need to follow your friends advice.

If it was mine I would leave it. It's not internal to the engine.

It's not going to explode onto the freeway, so to speak. :)

excrack.JPG
 

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I had 1970 2.02 heads with press in studs. A year before the angled spark plugs.
I bought the threaded studs and tapped the stud bosses.
I have that on my 283 resting in the basement.
The power pack heads were better for the 283.
Yeah, my 2.02's were too messed up, so I found a used set of 1.94's with the studs pinned and triple-cut seats. It ran pretty good with the reduced combustion chambers.
 
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Thanks everyone for your input. I am heavily considering tig welding.

I dont think that I can get the tools positioned right to try pinning.

I am going to buy some scrap heads and try it on them first to see how bad warpage would be. I think I can pull this off without removing the head
 

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You know dad suggested to me drilling a hole at the end of the crack and it isnt a terrible idea. It reduces the stress concentration in that area.
I’m not yer dad ..thats my story and I’m sticking to it...
 

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The threads could use a re-tap, but would still hold a stud if they're not like that all the way to the bottom.

Dremel the crack with a small diamond bit and tig it if you need to follow your friends advice.

If it was mine I would leave it. It's not internal to the engine.

It's not going to explode onto the freeway, so to speak. :)

View attachment 172867
On the NSR video abt clutch service is this tip on the exhaust gaskets.

700 deg. Copper silicon.


 

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