The term “superbike” gets tossed around pretty easily today. And it’s not hard to see why, with plenty of 200-plus-horsepower, two-wheeled road rockets to choose from right off the showroom floor.

When first unveiled at the Cologne Motor Show in 1972, the Kawasaki Z1 900 set the motorcycling world aflame with its sophisticated delivery of unmatched acceleration, speed, and looks. The Z1 rapidly ...