Exhaust collar fix, anyone else seen it done like this?

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I've not seen one like that before, but that's what makes England and the UK great, well executed, functional, top class quality engineering :lol: :lol: :lol:

It makes you wonder whether it would have been less effort to do the job properly :?:
 
I have re-repaired a few that had been done that way.
Of course ludwig has made it work for him. Jim

before
Exhaust collar fix, anyone else seen it done like this?


after
Exhaust collar fix, anyone else seen it done like this?
 
One word describes it.....BODGE! and the alternative, as shown in the previous post is so much better!
 
Hey if you don't like the Norton system, I bet you would hate the Harley shovel head system? It is a flange set up like Ludwigs, but they decided to only use one bolt for the whole flange.
Jim's repair is choice, real art form.

Cheers Richard
 
I remember being stuck far from home with stripped exhaust threads back in the 70's. The original nuts would not hold the pipes in.
I found that the Male part of a common brand of brass 1-1/2 pipe union would fit over the pipe and screw right in and hold.
Looked weird but worked.

Bruce MacGregor
 
Hello Forum. my exhaust threads stripped out many years ago. I repaired it by inserting an aluminium bronze sleeve similiar to the photograph. the big difference is I left a shoulder at the back of the sleeve so the exhaust rose did not have a tendency to push the insert out when tightened. To stop the insert turning when the rose is tightened two 1/8th pins were drilled in a fashion similar to a scotch key. made the interference fit 6/7 though tight , warmed the head, froze the insert, dropped straight in. Has not ever looked like coming loose and of course the aluminium bronze has a similar expansion rate to the alloy and is a lot harder and stronger. This method was used because I had no access to a lathe big enough to swing the head or a fixture to mount it. All that is needed is acces to a milling machine with a boring head. The ultimate repair would be to swing the head and thread the port oversize and make a screwed on the OD and ID bronze insert. Welding the port still leaves you with an alloy thread.
kind regards
B.Rad
 
B.Rad said:
Hello Forum. my exhaust threads stripped out many years ago. I repaired it by inserting an aluminium bronze sleeve similiar to the photograph. the big difference is I left a shoulder at the back of the sleeve so the exhaust rose did not have a tendency to push the insert out when tightened. To stop the insert turning when the rose is tightened two 1/8th pins were drilled in a fashion similar to a scotch key. made the interference fit 6/7 though tight , warmed the head, froze the insert, dropped straight in. Has not ever looked like coming loose and of course the aluminium bronze has a similar expansion rate to the alloy and is a lot harder and stronger. This method was used because I had no access to a lathe big enough to swing the head or a fixture to mount it. All that is needed is acces to a milling machine with a boring head. The ultimate repair would be to swing the head and thread the port oversize and make a screwed on the OD and ID bronze insert. Welding the port still leaves you with an alloy thread.
kind regards
B.Rad
Click to expand...


My inserts are threaded into the head with a coarse pitch thread. I keep two different OD inserts- one for threads that are just stripped and another to repair those that have already had an aluminum insert installed. Once in a while I will run into one that has been bored out till there is nothing left and they have to be built up with weld before they can be threaded. Jim
 
Re Jim's post.

As i said mate, a fully screwed insert is the ultimate repair. Was just a bit hard to see the details from the photo. you certainly do an outstanding job of the repair. you must have a decent workshop to do this quality of work. the before and after photos attest to the outstanding quality. As you would be aware there are some very dodgy fixes by "gurus" out there.

One question Jim, when threading the port do you swing them on a fixture or have a special tap for this. What bronze do you use, phosphor, manganese or aluminium.
the only reason I used an interference fit was i could not swing them to thread the port. Do you do other engineering work as well. I am only very new to this forum. Got a lot to learn.

Anyway well done on a very high quality repair process. Good to see sound engineering. Just for interests sake what would a all threaded repair like the photo cost.
kind regards
Bradley
 
B.Rad said:
Re Jim's post.

As i said mate, a fully screwed insert is the ultimate repair. Was just a bit hard to see the details from the photo. you certainly do an outstanding job of the repair. you must have a decent workshop to do this quality of work. the before and after photos attest to the outstanding quality. As you would be aware there are some very dodgy fixes by "gurus" out there.

One question Jim, when threading the port do you swing them on a fixture or have a special tap for this. What bronze do you use, phosphor, manganese or aluminium.
the only reason I used an interference fit was i could not swing them to thread the port. Do you do other engineering work as well. I am only very new to this forum. Got a lot to learn.

Anyway well done on a very high quality repair process. Good to see sound engineering. Just for interests sake what would a all threaded repair like the photo cost.
kind regards
Bradley
Click to expand...

The head is prepared for the insert in a CNC machine and tapped using a carbide thread mill under CNC control, then the insert which is finished on the OD only is torqued in with a light interference fit, then the CNC machine takes over again and cuts the inside thread in the aluminum bronze and finishes it to length.

I think the head in the photo by the time it was ready to bolt on the engine came to around 1100 dollars. It was a lot of money to put into something that ugly but it ended up being a very good RH10 head and he was able to keep his bike all original. Jim
 
B.Rad said:
Do you do other engineering work as well. I am only very new to this forum. Got a lot to learn.

Bradley
Click to expand...

I suggest you use the search function to see some of the fantastic stuff Jim has come up with.
 
Just an alternative viewpoint here.. while everyone is having a good belly laugh at the expense of the alleged "bodge" on the silver Interstate, consider this angle: The original head was iron, and the engine was solid mounted. Totally trouble free. The alloy later head has obviously weaker threads... but I contend that the Isolastic design and orbiting motion of the Commando engine relative to the other end of the pipes (yes, I know they're rubber mounted, but don't move as much as the engine, or as freely) causes some rocking motion at the pipe/head joint. That being said, a two bolt flange is a rather suitable design. As a career fabricator, I find that fix a clever one. No, it's not sexy like the sleeve/bronze insert/etc., and doesn't look as original as the other fixes, but from a "form follows function standpoint", I give the guy a B+ or maybe even an A. $.02
 
stockie2 said:
Hey if you don't like the Norton system, I bet you would hate the Harley shovel head system? It is a flange set up like Ludwigs, but they decided to only use one bolt for the whole flange.
Jim's repair is choice, real art form.

Cheers Richard
Click to expand...
Been there, lived the Shovelhead hell. Lame assed design.
 
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