The Harley Davidson engine is a copy of the 1898 or so De Dion-Bouton.
HD didn't originate it, and there is no way in hell they can keep
anyone else from building a v-twin engine. They lost their essential
point.

Offsetting the cylinders gives you a "rocking couple". But since the
Japanese imitation Harleys are for people who want approximate Harley
appearance and are mechanical idiots....