Video of Exhaust Thread Repair

[Duccout]

Here is a You tube link to Mid Engineering repairing my exhaust port thread. No wonder engineering is so expensive! https://youtu.be/amVLHsos48U

Colin

[blaat!]

That's cool. I always respect people who are not deterred by tricky task without precedent.

[Duccout]

Yes, Gary, the guy in the video repairing the head, will tackle anything, he is a proper old-school engineer. Unfortunately, here in Britain, those sorts of engineering shops have almost disappeared; when I was young they were everywhere but times change........When I was walking around Valetta a few years ago, I peered through an open door and inside was a workshop, full of machinery, and a gnarled old guy was working on something metal....... I almost popped in to say hello, but he probably would not have appreciated it!

Colin

[Ducadini]

Decades ago, a mate (who "occasionally" worked on Ducati's) had a 750 SS in his shop, front exhaust thread gone (this wasn't the only thing that was butchered, we later found out). We took the head off and on his daytime job, machining at a food packaging plant, he had a complete machineshop at his fingertips. While he machined the head, his colleague made the alu ring to fit . Day later, bike ran again. Two days later, I bought it .
Always admired his work (and the way he could put those big machines to good use : repairing Ducati's finest).

ciao
ducadini

[DBDBrian]

Yes a very interesting article, but for whatever reason, I am unable to locate part two ?

[Duccout]

Part 2 is pending.......

[DBDBrian]

Thanks Colin, look forward to it.

[Duccout]

Part 2 now posted!

[Duccout]

Part three now posted.

[DBDBrian]

That was certainly interesting to watch, with a successful outcome. Fortunately the exhaust thread was OK in the head I used with my rebuild, but after watching the video, I gave the ex thread issue a bit of thought as to how to overcome the situation, if ever I was confronted with the same problem.
I think my approach would be to try and reclaim the damaged, by screw cutting it oversize in the lathe, or if that was not possible, bore the head, and screw cut a completely new thread. Then make an oversize sleeve nut to suit in either event.
It would require a bit of scheming to mount it in the lathe, and would be a time consuming job, but it would overcome the need for welding.
I have repaired quite a few damaged threads in BSA 190 mm front brake drums using this method.
Just a thought on the matter.