History
The Yamaha QT50 — nicknamed the Yamahopper — is a Japanese noped: moped-style frame architecture without pedals. Yamaha built it from the late 1970s through the late 1980s, and it stood apart from European imports with turn signals, oil injection, and CDI ignition on nearly every year.
Its signature feature is a shaft final drive. A solid driveshaft with a torsion spring connects the transmission to a ring-and-pinion set in the rear hub — no exposed chain, no maintenance, and nothing to snag clothing. Paint and chrome were excellent for the era; plastic side covers and body panels are the parts that age badly on survivors.
The QT50 shares its drivetrain with the Tri-Zinger and PW50. Tuners swap 60cc Tri-Zinger cylinders, rev plates, and larger carbs — but stock bikes around 29–30 mph often four-stroke past 25 mph because Yamaha set them rich on purpose. Crank seals, carbs, rusty metal tanks, and petcocks are the usual restoration headaches on bikes that sat for decades.
Before chasing top speed, replace crankshaft seals and clean the carb idle circuit. Air leaks past 35-year-old seals turn a mild four-stroke into overheating and seizure once you bolt on a bigger cylinder.
Quick specs
| Type | Noped (no pedals) |
| Drive | Shaft to rear hub |
| Stock speed | ~29–30 mph |
| Lubrication | Oil injection (premix optional) |