Spprtster Headlight visor ?

[MCJim]

What is the notch on the back edge of the visor for, and what years was it used. I have seen this a few times. also what was the last year the smooth style visor/ cover used? 45653087-1963-harley-davidson-motorcycle-std.jpg

[jim d]

I think that it’s for the optional tachometer drive cable if I remember correctly.

[DEEBS47Chief1991]

And the smooth style would be used for electronic tach which does not use a cable.