There is one guaranteed fix for the problem that nobody has mentioned. Send the head to Leo Goff at Memphis Motorwerks. This and the solution to all things Norton are his speciality.

RoadScholar wrote:Owning a Norton is all about doing your own work; it makes the smile you crack in your helmet that much broader...
RS

Totally agree. These are the times I do wish I had at least a table top lathe. I probably could have made a fix myself this afternoon. I couldn't imagine, even if I had the money sending something off to have someone else make a bike for me. it is way to easy to throw money at old bikes having someone else fix them and zero satisfaction knowing you didn't do the work. This one just happened to be at the wrong place at the wrong time and made me buy it.

Brian: I' m open for business, call the web number for a beer.

T7275tr: Give Leo my regards, and thank him for the great job he did on my RH4 MkIII head!---no more advertising

BritBike: Good luck.

RS

Fred at old britt's suggested I try the split collets from the MIII exhaust with my 850 nuts and possibly doubling a crush washer. I am going that route as it is the cheapest at this point. I will probably have it redone at a future daye unless this doesn't work.

split collets were worthless, too small for the headers and the diameter wasn't the right size. So figuring I was going to have to remove the head again and send it out for a proper repair I tried grinding the excess off the exhaust port. I sealed the port and ground off enough to match the other head. Problem is I couldn't get it even so the threads are messed up at the start of the port. Is there a way to clean the threads up so I can get the nut to thread in the way it is suppose to or am I done? I tried for about 10 minutes to get the nut to line up right, but no matter what I tried it will not screw into the port. It looks like the first thread is messed up and I tried filing it but no good. Is there a way to fix the starter thread or am I done?

Make a scraper for the exhaust thread.

Get a 16d nail. Bend the last 1/2" 90 degrees. Grind a flat on the pointed end of the nail that is perpendicular to the thread when you grab the long part of the nail with vice grip. Scrape the aluminum out of the exhaust threads.

You might have better control when you cut down the thread insert if you use a wood rasp for the final cuts. The aluminum will clog the rasp. Clean it with a wire brush. A file for steel will give a finer finish, but it will clog up very quickly.

Greg

Thanks Greg, I'll give it a try.

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?

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.

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.

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.

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.

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

Jean

Jeandr wrote: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

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

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.