Engineering compromises leading to exhaust threads stripped (2012)

Sounds a bit on the tight side to me...

Yeah. The previous figure was bollocks. I just discovered my mistake and have revised #105. The exhaust nut is of course hollow. I hope this revised figure makes more sense.

My caveat in #105 still applies.

-Knut
 
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My way of wiring the exhaust rings also 'live loads' the lock wiring ensuring the rings do not come undone


I think Jim's spring set up is a lot neater than that, looks a bit rough to me, but then I have no problems with my exhaust rose coming lose
 
I'm good with whatever keeps them from backing off. All of the above diverse methods prove many minds are addressing the issue in differing ways giving bystanders a set of viable working choices rather than ordering a 'magic method' they've never laid eyes upon..... Hence money on wings, and the damned things still loosen & leak chewing up threads..... Good show gentlemen.
 
concours, any updates on the mounts? They holding up OK?
 
I’ve been called an idiot before.
So, all are idiots who’ve had to deal with those problem?
Of course.
I fix stuff.
Lots of it.
Wildly complex & expensive stuff sometimes.
Do/say what you will.
I offered to share for free an idea.
Seams it’s working well.
Low cost.
Many bikes will never need the solution, because, well, their owners aren’t idiots.
And would NEVER ride them fast or far, never mind BOTH at once. :p
Like my oil-tight primary fix, clearly, non-idiot owners don’t need it either.:cool:
Merry Christmas:D
I see you own a Rocket III. Ever have a problem with top end bolt holes stripping, especially the covers? Nobody called you an idiot. They could have made the bolts bigger and the threads stronger, but they didn't. Norton could have made the exhaust roses affix with two bolts like 90% of all modern bike exhausts, but they didn't. Stripping a thread is a numbskull fuckup we all have done at one time or another. Unless you bought your Norton new, someone else undoubtedly laid hands on it previously. A majority of the few threads I have buggered were weakened by improper ham-handing and were waiting to fail. If threads could not be stripped, they'd be idiot-proof. Only ones I've ever laid hands on that couldn't were 6" diameter gas turbine studs. In the old days, they were torqued by a slugging wrench, comealong and a sledge with an engineer watching closely. Now they are tightened by a machine called a Hy-Torq bolting tool. Pretty idiot-proof.

Nothing wrong with eliminating the crossover to gain more thread purchase. But they still can be stripped.
 
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"I see you own a Rocket III. Ever have a problem with top end bolt holes stripping, especially the covers? "

No, but fork seals are leaking from repeated MAD WHEELIES..... self inflicted wounds I suppose... That, and rear tires don't seam to last....
 
"Norton could have made the exhaust roses affix with two bolts like 90% of all modern bike exhausts, but they didn't. Stripping a thread is a numbskull fuckup we all have done at one time or another. Unless you bought your Norton new, someone else undoubtedly laid hands on it previously. A majority of the few threads I have buggered were weakened by improper ham-handing and were waiting to fail. If threads could not be stripped, they'd be idiot-proof. Only ones I've ever laid hands on that couldn't were 6" diameter gas turbine studs. In the old days, they were torqued by a slugging wrench, comealong and a sledge with an engineer watching closely. Now they are tightened by a machine called a Hy-Torq bolting tool. Pretty idiot-proof."

I would offer, that over tightening is only ONE WAY for threads to get damaged. Vibration, if there is a slight amount of movement, can completely destroy threads.

As for big fastener experience, never any 6", only 2" on Reactor Coolant Pumps. We measured, heated, stretched to dimension using torque multipliers, measured, let cool. Neolube to prevent galling. https://neolube.global/dry-film-lub...y0BXPPwxfuSCGYxzOIIR9GysQUMCpP3BoC3PAQAvD_BwE
 
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I would offer, that over tightening is only ONE WAY for threads to get damaged. Vibration, if there is a slight amount of movement, can completely destroy threads.
I bought my 850 new in 75. In 1981 I had to have the exhaust threads repaired. Why? Because of these things... :mad:

Engineering compromises leading to exhaust threads stripped (2012)
 
Over the years I have rebored and sleeved hundreds stripped ports with aluminum sleeves welded in. Cosmetically it is not pleasing but seems to work.I know there are other methods but not as price effective.I have recommended using the norvil bronze nuts.They are always the same exact size. Walridge motors in Canada is were I get them.I found the aftermarket steel ones are all over the map for size.They must be chinesium because I have never seen threads so poorly made. I fit them as I get them and just recommend a small smear of antiseize on install.Just my take I know there are other methods.In general use a thread should be used at least the same length as diameter. For 1/2" at least 1/2" long so since the exhaust is almost 2" dia so a 2" long thread would be better but that is not the case ,plus steel thread in aluminum with the heat factor is a bad situation. It is too bad a stud set up like the old 650 yamaha was not used .My 2 cents anyway.
Bruce
 
Concours writes: "A majority of the few threads I have buggered were weakened by improper ham-handing and were waiting to fail........I would offer, that over tightening is only ONE WAY for threads to get damaged. Vibration, if there is a slight amount of movement, can completely destroy threads."

In my experience, if you stripped the exhaust threads in a Norton head, the threads were already buggered anyway. And if the threads are in good shape, you aren't going to strip them by over tightening them. I am not sure it is even physically possible. Maybe if you used a 6 foot bar and jumped on it......
I agree with the part about vibration destroying the threads. But I am convinced the vibration is created by not tightening them enough to begin with.
 
Over the years I have rebored and sleeved hundreds stripped ports with aluminum sleeves welded in. Cosmetically it is not pleasing but seems to work.I know there are other methods but not as price effective.I have recommended using the norvil bronze nuts.They are always the same exact size. Walridge motors in Canada is were I get them.I found the aftermarket steel ones are all over the map for size.They must be chinesium because I have never seen threads so poorly made. I fit them as I get them and just recommend a small smear of antiseize on install.Just my take I know there are other methods.In general use a thread should be used at least the same length as diameter. For 1/2" at least 1/2" long so since the exhaust is almost 2" dia so a 2" long thread would be better but that is not the case ,plus steel thread in aluminum with the heat factor is a bad situation. It is too bad a stud set up like the old 650 yamaha was not used .My 2 cents anyway.
Bruce
Hi Bruce. Do you still do this repair for owners? I've recently sent my head off to a fellow in Ottawa and had them done....he uses a bronze/alu sleeve and fixes in with a locktite product...similar to what Jim Comstock does apparently (though I believe he uses epoxy).
 
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