Here are some specs for the 1970 Honda ATC 90: Engine: 90cc Transmission: 4-speed Price: $595 in 1970 No Reserve: 1970 Honda ATC 90 The Honda ATC 90 was Honda's first three-wheeled all-terrain cycle, originally called the US90. The name was changed to ATC90 after Honda trademarked the "All Terrain Cycle" name in 1973. The ATC prefix was used for all Honda three-wheeled vehicles until production stopped in 1987. Here are some other notable features of the Honda ATC 90: The triangular footprint was designed for stability, traction, and maneuverability on tricky surfaces. The prototype originally used treaded motorcycle-type wheels and tires, but these didn't work well on soft terrain. The breakthrough came when the prototype was reconfigured to use 22-inch diameter balloon tires from an Amphicat six-wheeler.