The swap from Wico vertical magneto to Fairbanks Morse vertical on 1955 KHRM:

This change occurred in late 1954 for the 1955 season.

Was it just for costs reasons or can we deduce from that change that H-D needed a smaller magneto for an engine with carburettor on the right where it would obviously foul the taller Wico XV 1922 unit?

I.E. did the Sportster engine as we know it started life in 1954 as an internal prototype?

It is also certain that the OHV “KL” is from 1953, judging from its cycle parts (see photo in K/Sportster gallery) and that the 1956 KH/KHK frame was basically made that way to suit the Sportster engine…

Anybody out there cares to speculate?

Patrick