exhaust port repair (updated)

Status
Not open for further replies.
Re: exhaust to head issues and question

Well as suggested in an earlier reply, the insert on the right side pulled out completely when I tried to tighten the exhaust nut. Chalk it up to a poor job done by someone that did not know how to do the initial repair and for my part I figured it was best to try and grind it down to see if I could get it to fit right. I got it ground down, but the original repair just couldn't sustain the torquing of the exhaust nuts. I do feel better for at least trying to make it work out. I will have to try and call Leo to see if they can try and salvage my head. Does anyone know if an insert pulls out if the repair can generally be done again?
 
Re: exhaust port thread repair issues and question

A really good way to fix a thread, like an exhaust thread, when the first few threads are ruined is this. Get a tap with the same number of threads per inch. Common on many british machines is 26 tpi. The tap doesn't need to be big. You just need the same number of threads per inch. Put a handle on it and use it like a scrapper going around the thread. This is similar to the nail idea but it works way better. The good threads further in the head will guide the tap and enable you to do a really nice job.
 
Re: exhaust port thread repair issues and question

Or an old exhaust nut, cut into perpendicularly in four places through the threads. I have one in my "specialty tools" collection, use it to clean out carbon once in a while and keep the threads in good order.
 
Re: exhaust port thread repair issues and question

This is what actually happened. Insert pulled out so there is no repairing threads. I have to see if this can be redone on both sides. I did have to cut the insert off the nut, but I am unsure if there is enough meat left where the old repair was done. This is what happens sometimes when a local does a repair on an unfamiliar piece. Wish I had enough money for a new fullauto head.

exhaust port repair (updated)


exhaust port repair (updated)
 
Re: exhaust port repair advice needed

I need someone that has experience working with heads to look at the two picture I posted and tell me if you think this head is salvageable? It looks as though this is the second insert repair. There is a thin layer of loose aluminum left all the way around the port as if there was a second insert that was bored around but not completely removed. Then it appears another insert was installed over the thin material left in the port. I have no experience with this sort of thing, but it sure doesn't look like there is enough material to fix this head again. Anyone kind of have an idea. I don't want to ship this thing out only to be told it is garbage and pay shipping both ways for nothing. I do have the head off again and can post more pictures if needed, thanks.
 
Re: exhaust port repair help needed

Take a look at this thread exhaust-port-repairs-t3373.html?hilit= exhaust I think the way Ludwig has done it is the best, it does not look original, but it won't ever come loose. If you look at the new Norton, they have the same exhaust hold down method, but with 3 studs instead of 4, a 25% saving :lol:

Jean
 
Re: exhaust port repair help needed

Jeandr said:
Take a look at this thread exhaust-port-repairs-t3373.html?hilit= exhaust I think the way Ludwig has done it is the best, it does not look original, but it won't ever come loose. If you look at the new Norton, they have the same exhaust hold down method, but with 3 studs instead of 4, a 25% saving :lol:

Jean

Jean, both ludwig's and your solution look fantastic and I am not concerned with original on this bike, but I do not have the ability, tools or time to make a nice repair like the two of you did. I have to send my head out to someone recommended competent, but don't know if the head is even able to be salvaged as it is there is no aluminum left to work with once the first insert is removed. You can see where it broke off the outer most bits of aluminum. If I was able, I would use either of the solutions in the thread you pointed me to, but don't know of anyone near that could do the repair, thanks.

Tim
 
Re: exhaust port repair help needed

I can't see any reason why it couldn't be built back up with weld and pretty much any of the normal thread repair methods applied.
 
Re: exhaust port repair help needed

I had this problem ie a bronze threaded insert came out on an 850 head, Mick Hemmings fixed it with an alloy insert specially made and this was welded back into the head. Charged his std rate for thread repair, sounds like you need to send it to Micks NA brother which may be Leo.
 
Re: exhaust port repair help needed

britbike220 said:
Jeandr said:
Take a look at this thread exhaust-port-repairs-t3373.html?hilit= exhaust I think the way Ludwig has done it is the best, it does not look original, but it won't ever come loose. If you look at the new Norton, they have the same exhaust hold down method, but with 3 studs instead of 4, a 25% saving :lol:

Jean

Jean, both ludwig's and your solution look fantastic and I am not concerned with original on this bike, but I do not have the ability, tools or time to make a nice repair like the two of you did. I have to send my head out to someone recommended competent, but don't know if the head is even able to be salvaged as it is there is no aluminum left to work with once the first insert is removed. You can see where it broke off the outer most bits of aluminum. If I was able, I would use either of the solutions in the thread you pointed me to, but don't know of anyone near that could do the repair, thanks.

Tim

Tim, why not ask Jim Comstock (aka commoz), he has a post on how he does it here documentary-exhaust-thread-repair-t4517.html?hilit=exhaust The head he fixed has the exact same problem you have.

Jean
 
Re: exhaust port repair help needed

If anyone out there in Norton land needs help with a stripped exhaust thread head I'm here to help. I purchased the proper tap and then have inserts cut and welded then clean them up to blend them in. All it will cost you the price of shipping back & forth here in the lower 48, USA. Unless, you feel like making a donation to the beer fund. :D We have done many repairs here in the chicagoland area.

cheers!

Tim
CNOC & INOA
Member
 
Re: exhaust port repair help needed

That's a very nice offer, Tim. I'm sure you'll get some takers on it. I've done a couple repairs on my own heads by turning inserts and welding them in, and it's pretty time consuming, so it's no small thing to offer it for free (or for beer money) .

Ken
 
Re: exhaust port repair help needed

I went and picked my head up today from Tim_S and got the valves put back in it. I probably won't work on the bike again until the weather goes bad, but A big thanks to Tim and those guys from the chicago norton owners club for helping me out. It only cost me a lunch for Tim and a small donation to help fund their repair coffer, even got a complimentary CNOC pin, again thanks Tim!
 
Re: exhaust port repair help needed

I have never experienced such a helpful bunch of fellows as are on this forum.

Thanks everyone,
Dave
69S
 
Re: exhaust port repair help needed

The CNOC is always happy to help out. At the same time it's nice to actually meet up with you guys and share our experiences. These forums are cheaper than a therapy session. Clubs and support groups like yourselves make it all worth while.
We all expect to see the finished bike :) once your done Tim. :!: See you on the road.......


Tim_S
 
Re: exhaust port repair help needed

Can I see a picture of the process, or the finished job please.
I have to do my Mk3 850 as it spat the left thread. Had to wire it up to get home, about 2500 kms.

exhaust port repair (updated)


graeme
 
Re: exhaust port repair help needed

I'll take a picture Sunday after I get off work. I know the head was in real sorry shape and previous repairs were done poorly. Tim said there didn't appear to be a lot of material to work with because the holes were augered out so bad and it did have quite a big hole right under the port. A tough repair I didn't think was possible, but new inserts were made, welded and bench tested for strength. I don't really know what I want to do with the bike yet. Part of me says to leave it in stock guise, but the other half says customize it. I have the all the interstate parts already except the low exhaust and the roadster parts, but don't know if I like the interstate tank yet.
 
Status
Not open for further replies.
Back
Top