After his initial prototype of the late 1860s, Roper built a new and revised version in 1894, based on the then state of the art safety bicycle frame type.

[12][13] The AMA Hall of Fame and motoring author Mick Walker put Roper's steam velocipede at 1869, in accordance with the date of the machine in the Smithsonian.

[1][15] Classic Bike editor Hugo Wilson says the existence of an 1869 patent for the Michaux-Perreaux gives it "the better claim to 'first'", even though the Roper was built around the same time.

[11][20] Instead, the recognition should go to the internal combustion Reitwagan because it blazed a trail that was followed by the thousands of successful motorcycles subsequently built in the 20th century.

"[11] By this logic, when some future form of motorcycle propulsion takes over from internal combustion, everything that went before will be disqualified, because it turned out to be a dead end technology.

[1][11] The reason, they say, is that it did in fact pioneer successful motorcycle technologies, including the twistgrip throttle control, and the frame geometry and engine placement used by the motorcycle as we know it today, while the Reitwagen was exceedingly crude, failing to employ the well understood principles of rake and trail to remain upright by movements of the front fork, and turn by leaning.

[22] Trail, also called fork offset, is an element contributing to the stability of bicycle and motorcycle dynamics,[22] and the lack of it was one reason why the Reitwagen had to rely on two outrigger wheels to keep it from falling down, so it remained vertical and was steered much like a tricycle.

[34][35] Motorized bicycle pacers had recently emerged with crude deDion-based gasoline engines, but these were unreliable and often disappointed racing fans.

[34] Roper was known to regularly ride this machine, which he called his 'self propeller', from his home at 299 Eustis Ave [37] in Roxbury to the Boston harbor, a distance of 7 miles, the engine's maximum range.

Roper claimed his machine could 'climb any hill and outrun any horse', and American Machinist magazine noted, "the exhaust from the stack was entirely invisible so far as steam was concerned; a slight noise was perceptible, but not to any disagreeable extent.".

He was then encouraged to give a demonstration of maximum speed, and was timed at over 40 mph, when a 'sudden pallor' was seen on his face, and his machine wobbled to a stop, Roper falling off his cycle.

It was the fourth venue for the motorcycle design show which had first opened at the Guggenheim New York in 1998, where the Michaux-Perreaux velocipede had been the first machine viewers saw upon entering the rotunda of the museum.