Lambretta stud bolts with M7 and M10 threads for repairing cylinders with damaged threads at the exhaust port.

M7 thread: 17 mm
M10 thread: 10 mm
Unthreaded shank: 7 mm 

The ideal stud bolt for repairing any cylinder with an oval outlet and a damaged thread. The thread on the cylinder is cut to M10x1.5, and then the stud bolt is glued in place with threadlocker.