Exhaust thread repair

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GRM 450

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We have been to the Australian GP at Phillip Island, traveling back to Brisbane now and the left exhaust thread has given up so the nut is wired around the head which will get me home. What is the recommended repair? Inserts or weld and re tap? The Norton has been a perfect tourer and easily keeps up with the moderns and is heaps more fun. Graeme
 
Don't know who does it over there, but I generally think there are inserts made or pre made and then welded in place. There are several places in the states. I had to just have a repair redone due to the repair being done incorrectly the first time. Just make sure you have someone do it that knows what they are doing or it could end up a mess.
 
Not sure about Brisbane, but if there's no-one up there experienced in port thread repair I'd suggest you give Dave Blissett in Sydney a ring (he's in Ashfield). Dave's a retired machinist and has a full machine shop at home. He's very well known in Norton and classic racing circles, and does a lot of work for bike shops in Sydney. Dave welds the ports and then recuts the thread on his mill. I've seen a head repaired by Dave and it was a thing of beauty.
Another alternative if you don't mind some shipping costs is to send the head to Forum member Comnoz in the US. I recently bought an RH10 head off US eBay and had it shipped directly to Jim and he inserted bronze thread inserts. It was a superb job. There's an excellent thread on here too that you should be able to find if you search under exhaust port repair.
I envy you your Phillip Island trip. Last time I rode a Commando that far was back in 74 when I rode my Mk11A Interstate from Noosa back to Canberra (in one day mind as my girlfriend (now wife) was waiting at home, which is more than enough incentive to get a 20 year old male through the sore arse pain barrier).
All the best with the post repair. Bill
 
I was talking to BJ's bikes and bits only yesterday about the same problem.
They send them out to weld and re-thread. About $ 150.oo per port.
 
Thanks for the replys, I had to stop in Sydney and get some thicker Gage wire as the Mk1 design was too thin and only lasted a couple of hundred ks then broke. The Mk2 design looks like it might last the distance to Brisbane. We are at Taree tonight then up the Oxley highway tomorrow. I will post some pics when I get home in a couple of days. Norton is performing admirably and quite the GENTLEMENS conveyance. Graeme
 
britbike220 said:
Don't know who does it over there, but I generally think there are inserts made or pre made and then welded in place. There are several places in the states. I had to just have a repair redone due to the repair being done incorrectly the first time. Just make sure you have someone do it that knows what they are doing or it could end up a mess.
Click to expand...

Mine's the same. Repair insert on one side, but it's almost time to get it redone. Don't know why it's just the one side, but I'm hoping it lasts until the head needs rebuilt.

Have a good trip
 
If you're in Brisbane I'd give Solo Tooling in Albion a call. They're in the phone book. ( No internet presence, they're old school).
 
Bummer about the zorst thread but glad the trip went well Graeme, hope you got some decent weather in the end. That's quite a few k to cover, Norton or otherwise - going to post up a trip thread? With lots of pics?

On a similar line, was riding with my mate on his old 450 desmo (me on the Pantah) when the zorst mount came loose and it blew out the gasket a long way from home. He was worried about burning out his exhaust valve through lack of back pressure. Small town we were in had a little hardware shop with not a great range of things, but I had the idea of buying some mains house wiring cable - large diameter single Copper conductor - and wove it into a fair facsimile of a gasket. Got him back home safe and sound. Useful stuff wire.
 
GRM 450 said:
Thanks, weld and re thread, or insert?
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He'd probably make up an insert. I haven't had an exhaust repair done by him, but plenty of other stuff. Any machining that I need, I go there. Any welding , I go to a bloke in Enoggera. He's a brilliant welder , but err, difficult to deal with.

When I had my exhaust repaired, it was done in England. They made a bronze insert and pressed it in. It's still there :)
 
Some fencing wire lasted nearly 2000 miles and got us home.

Exhaust thread repair


Now for the big clean and head off to repair the exhaust threads.

graeme
 
I rang Geoff Howie at Solo Tooling in Albion, (this is probably usefull for Brisbane Nortoneers, Pommie John and Combat Col) Geoff has Paul Bushell weld up the faulty thread and he then recuts the new thread.
He said he needs the exhaust nuts as some nut threads are not the same, especially in later Commandos when the tooling was wearing out.
graeme
 
GRM 450 said:
Some fencing wire lasted nearly 2000 miles and got us home.

Exhaust thread repair


Now for the big clean and head off to repair the exhaust threads.

graeme
Click to expand...

Note to self: include bailing wire to tool kit! :roll:
 
GRM 450 said:
I rang Geoff Howie at Solo Tooling in Albion, (this is probably usefull for Brisbane Nortoneers, Pommie John and Combat Col) Geoff has Paul Bushell weld up the faulty thread and he then recuts the new thread.
He said he needs the exhaust nuts as some nut threads are not the same, especially in later Commandos when the tooling was wearing out.
graeme
Click to expand...


I would never presume to question Geoff's expertise, but I once had a BMW head welded on the inlet port and it seemed to lose its heat treatment and the inlet valve seat began to move in the head after the welding was done.
Maybe it's not a problem with Norton heads, or maybe the guy who did my BMW didn't know what he was doing.
just thought I'd mention it so you can ask the question.

John
 
GRM 450 said:
That's a good point John, I'll ask the question when I see Geoff.
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Don't tell him a pommie fella with a Norton and a BMW told you to question that...he'll know who it was :)
 
Finally got the head to Geoff today, I asked about the heat effecting the head and seats etc. He said that it's heated first then welded and he's never had a seat come loose.
It will be gone for a few weeks, so I'll have to wait and see the finished job.
graeme
 
Head exhaust threads repaired, welded up and re threaded to suit the thread on the nuts.
Both threads on the nuts were slightly different, so the head threads were cut to suit each nut. (1977 Mk3, made with worn out tools? Or reject parts?)

Exhaust thread repair
 
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