Originally Posted by
Salubrious
I'm a bit dubious. You really don't want that shift cable to be any tighter than needed! I go by the extension of the toggle chain method simply because I don't trust that the chain and associated hardware is correct and original.
When mounting the shifter (especially 4 speed) don't fasten the shifter on a curved section of the handlebars, choose a straight section. A curved base buckles the receiver plates and the pawls inside trigger mech can jump off their cams.