NORTON TWIN EXHAUST THREAD REPAIR SERVICE Using our own CNC Milling machine we helical interpolate a new thread into the exhaust port to accept one of our CNC MACHINED bronze inserts. The new thread is then CNC milled inside to fit the new rose nut exactly. Because of the nature of CNC machining the external and internal threads are machined coincidentaly(both thread starting in the same position with one thread inside the other) giving a very strong insert. These bronze inserts are threaded and locked in and WILL NOT jack out we have instock 3 sizes of bronze repair inserts to cope with previous repairs but in the last resort…