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Stripped exhaust port thread

Posted: 26 Jun 2022 02:10
by 70sbikes
My 1976 3 1/2 Sport has a stripped exhaust port thread. I'm after recommendations on who can fix this. I am in Australia, but I'm willing to post the cylinder head overseas.

Cheers

Trevor

Re: Stripped exhaust port thread

Posted: 26 Jun 2022 06:08
by MickeyMoto
It may be cheaper to source a new head.

Re: Stripped exhaust port thread

Posted: 26 Jun 2022 07:32
by hendre
maybe you can show this vid to a local machine shop and they can solve it for you?
https://www.youtube.com/watch?v=ZfFbA9Y3jHw

the author of the video is on the forum (EVguru) and he may do it for you (did some in the past)
other adresses (from another topic):
https://www.lussoveloce.com/
https://www.morinispecial.it/joomla/ind ... cle&id=177

Re: Stripped exhaust port thread

Posted: 28 Jun 2022 04:25
by Daddy Dom
Try Gary Jolly at Reliable Engineering in Adelaide.
DD

Re: Stripped exhaust port thread

Posted: 28 Jun 2022 07:44
by 70sbikes
It may be cheaper to source a new head
By "new" I assume you mean used? I thought about that, but I reckon there wouldn't be many used heads out there with pristine threads. The aluminium is now 45+ years old, and has been through countless heat cycles, meaning I'd probably end up back where I am now...
Try Gary Jolly at Reliable Engineering in Adelaide
I actually found another motorcycle engineering place in South Australia! I reckon Zuckerberg was listening in to my conversations, because this place popped up in my feed. I was scrolling through his posts, and the one that caught my eye was a Norton Commando head with beautiful bronze inserts. I spoke to him, and he has actually done Morini exhaust threads in the past. Heads are now boxed up and will be posted tomorrow. It's not going to be cheap, but given 3 1/2 Sports are fetching around $15,000 AUD, it will be worth it!

Re: Stripped exhaust port thread

Posted: 06 Nov 2022 10:54
by sheddweller
Would you mind posting some contacts for the engineering business in SA that has done inserts for Morini heads? I am in Queensland and have some damaged threads, as do at least 2 other local Morini owners. Thanks, Garry

Re: Stripped exhaust port thread

Posted: 08 Nov 2022 12:41
by 70sbikes
Martyn Adams at MDA Motorcycle Engineering.

https://www.facebook.com/search/top?q=m ... ngineering

martynadams.eng@gmail.com

0421 874 513

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With postage, it cost around $1,200 AUD. Before the naysayers reply with "The bronze inserts won't stay fixed in place", Martyn does the same work on Norton Commandos (and has done for many years), knows what he is doing, and has nothing but positive feedback on his work. He's a frickin' genius! Get it done before he retires or shuffles off the mortal coil!

Trevor

Re: Stripped exhaust port thread

Posted: 08 Nov 2022 16:57
by MickeyMoto
That looks like a very nice job. Shame he is in Oz.

Re: Stripped exhaust port thread

Posted: 08 Nov 2022 20:59
by norbert
Sören the vikingo is doing the job as well (you´ll find it scroling down :wink: )

http://morinist.dk/morini/tyskdele.php

Re: Stripped exhaust port thread

Posted: 09 Nov 2022 02:02
by 70sbikes
I didn't mention that Martyn's inserts meant the "dome" in the exhaust port was machined off. To get the exhaust pipes to fit properly I had to grind away the taper on the half-rings. This took a while, as I didn't want to ruin the hard to obtain rings, so it was grind, check the fit, grind, check the fit, until they were perfect. Martyn also recommended using two exhaust gaskets.

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