Beauty of output nut is soft “flange” to peen into recess to lock it, output shaft recess for speedo drive ball, input groove for lock tab.
Photo not good example cos nut here is 2nd (or. 3rd or 4th) hand but proper Guzzi content, recycle forever
I did use tab washer as well here but every other (new) one I’ve used I just punched flange into recess to lock
Simple, quick and cannot come undone, tab only belt and braces, not necessary.
