Dunstall 810 Cylinder Repair Question

I'm looking for inputs on repairing some damaged thread inserts in a Dunstall 810 cylinder. I've posted the details at the end of this thread in the Wanted section.

dunstall-810-cylinder-t18897.html

If anyone has had a similar problem and solved it, I'd certainly welcome their comments!

Ken

Yeah, I had problems and solved it. I bought a cylinder from Left Coast Racing and threw the Dunstall in the heap after about 3 tries. Jim

comnoz said:

Yeah, I had problems and solved it. I bought a cylinder from Left Coast Racing and threw the Dunstall in the heap after about 3 tries. Jim

Click to expand...

Ah, those were the days. I'm not sure I ever broke even on selling those cylinders, but at least it was educational. When Steve Maney started producing his alloy cylinders in higher quality than the ones I was selling, I was happy to quit importing mine. I think at least 10% of them were broken when customs inspectors didn't re-pack them properly. At least I had plenty of damaged and repaired ones to use in my own race bikes.

Ken

Wouldn't the inserts with weakened surrounds have to be removed then bigger ones or weld fill to retap? Maybe drill thin then Nitric acid to dissolve the remains til can be removed. I've planned an external head clamp down and recently saw such on garden pull engines though only something I'd likely do on Commando.

My 750 Dunstall barrels have steel inserts which are holding up well, and I made up some long head bolts to use as much of the available thread as possible.

Not sure if this is as easily achievable with the 810 barrel - two of the holes are pretty close to the liners