Excelsior Super X

[2] Arthur "Connie" Constantine, Assistant Chief Engineer at the Harley-Davidson Motor Company, drew up plans for a mid-sized V-Twin to compete against the Indian Scout.

When he presented the unauthorized project to co-founder Walter Davidson, he was reprimanded for wasting the company's time.

[2][5] The Super X had originally been envisioned as a competitor to the Indian Scout which was, at the time, powered by a thirty-seven cubic inch V-twin engine.

[5] These "Streamline" models had tanks that hid the top tube of the frame and wide front fenders with holes for the forks to pass through.

During 1931, the Indian 101 Scout was replaced by a Scout model based on the heavier Chief frame, the sport solo DLD was added to the D and DL in the Harley-Davidson line, and the Excelsior-Henderson concern ceased production of motorcycles upon the order of its proprietor, Ignaz Schwinn.