That bike was code-named Project Nova, and the final prototype is one of many never-before-seen concept vehicles featured in “Collection X: Weird, Wild Wonders of Harley-Davidson,” on display at the Milwaukee museum now. Designed in partnership with Porsche, the Nova was powered by a short-stroke, liquid-cooled, DOHC V4 rated at 135 horsepower. The chassis featured an underseat radiator and fuel tank, with a rim-mounted front brake that predated Buell’s ZTL design by more than a decade. It’s an innovative, compelling machine that almost certainly would have shifted customers’ perceptions of Harley-Davidson to an aggressive and daring brand. Unfortunately, parent company AMF killed the project early in ’81. It was deemed too risky and expensive, and funds were instead diverted to Evolution engine development.