Yamaha entered the three wheeler market in 1980. Yamaha started with 125cc recreational three wheeler that would remain the foundation of their line through 1985, the YT125 featured a 2 stoke engine with sealed airbox with snorkel intake, an autolube oil injection system, and featured a narrow tunnel above the engine that was advertised to make the machine easier to keep stable in precarious situations. Advertising pointed out the durability of the tires, at a time when Honda ATCs were still known for relatively weak low-pressure balloon tires.
Yamaha followed the YT125 with the introduction of the YT175 in 1982.