Yamaha two-stroke street bikes span three decades, from a 123cc single in 1955 to a liquid-cooled twin that reached America in 1984. Along the way, the company went from a bike modeled on a German design to selling a road-going replica of a Grand Prix racer.

These eight models trace that line in order. Each figure comes from Yamaha’s own collection records, auction listings or period-spec references, and we name the source where they differ.

1. 1955 Yamaha YA-1 two-stroke single

Yamaha Motor’s first motorcycle was a 125cc single that earned the nickname “Red Dragonfly,” or Aka-tombo. Yamaha says the name came from its reddish-chocolate paint and cream-white tank, which stood out against the all-black bikes of the day. The first prototype was finished on August 31, 1954, and full production began in January 1955. Yamaha also says the bike was modeled after the German DKW RT125.

According to Yamaha’s collection page, the YA-1 used an air-cooled 123cc two-stroke single that made 5.6 PS at 5,000 rpm. It won the 3rd Mt. Fuji Ascent Race in July 1955. Then, over three years, Yamaha sold 11,000 of them at ¥138,000 each.

2. 1957 Yamaha YD-1

Next, the Yamaha two-stroke gained a second cylinder. The YD-1 was Yamaha’s first motorcycle with a twin-cylinder engine, the company says. Its styling also leaned sporty at a time when utility bikes dominated the Japanese market. However, Motorcycle.com notes that the 250cc twin was an improved version of another German bike, the Adler.

Specifically, Yamaha lists the 1957 YD-1 with an air-cooled 247cc two-stroke twin. It made 14.7 PS at 6,000 rpm and weighed 140 kg. In addition, Yamaha says the bike’s compact size fit the Japanese physique, and it sold for ¥185,000.

3. 1959 Yamaha YDS-1

Yamaha calls the 1959 YDS1 “the first full-fledged sports motorcycle by a Japanese maker” in its official timeline. That’s the company’s own claim. Still, the specs back up the sporting intent. Motorcycle.com says the YDS-1 put a tuned-up version of the YD-1 motor into a double-cradle frame.

On its YDS-1 collection page, Yamaha lists a 246cc air-cooled two-stroke twin making 20.0 PS at 7,500 rpm. That’s a big jump from the YD-1’s 14.7 PS. Yamaha also credits the bike with the first Japanese-made five-speed transmission and a tachometer in the instrument panel. Moreover, it accepted various race kits.

4. 1973 Yamaha RD350

The RD350 arrived in 1973 as the successor to the R5. Its biggest change was the intake, because Yamaha swapped the R5’s piston-port setup for reed valves. The engine was a 347cc air-cooled two-stroke parallel twin, and it drove through a six-speed gearbox, SlashGear reports.

Power figures differ by source. SlashGear and MotorcycleSpecs both give about 39 horsepower at 7,500 rpm, while Motorcycle.com says 35. As for prices, SlashGear says a 1975 RD350 sold for $6,200 at a 2024 auction, and a 1973 model later sold for just under $5,500.

5. 1980 Yamaha RZ250

In 1980, development across the industry favored four-strokes, Yamaha says. Even so, it bet on the two-stroke again. Its RZ250 collection page says the bike helped revive interest in two-stroke engines. Its styling drew on the TZ250 racing motorcycle.

Under the tank sat a liquid-cooled 247cc two-stroke twin. It made 35.0 PS at 8,000 rpm, which Yamaha describes as 140 horsepower per liter. The RZ250 also used Yamaha’s Monocross rear suspension and light cast wheels. In total, it weighed 139 kg and cost ¥354,000 new.

6. 1983 Yamaha RZ250R

Three years later, the RZ250R kept the 247cc liquid-cooled twin but added a key piece of technology. According to Yamaha, it was the first production model to use the Yamaha Power Valve System, or YPVS. Iconic Motorbike Auctions describes YPVS as a computer-controlled valve that could adjust exhaust port timing.

As a result, output rose sharply. The RZ250R collection page lists 43.0 PS at 9,500 rpm, up from the RZ250’s 35.0 PS. In addition, Yamaha fitted electronic ignition and a racing-inspired frame. The bike weighed 145 kg and sold for ¥399,000.

7. 1984 Yamaha RZV500R

The RZV500R took the Yamaha two-stroke idea furthest. Yamaha describes it as a production replica of the YZR500 that Kenny Roberts raced in the 1983 World Championship. It was also, by Yamaha’s account, the first production motorcycle with a two-stroke V4.

The RZV500R collection page lists a liquid-cooled 499cc V4 making 64.0 PS at 8,500 rpm. Interestingly, the front cylinders used crankcase reeds, while the rear pair used piston reeds. Yamaha also mounted the rear shock horizontally beneath the engine. At ¥825,000, it cost more than twice as much as the RZ250R.

8. 1984 Yamaha RZ350

Finally, the liquid-cooled twin reached the United States. Motorcycle.com’s Yamaha history says the RZ350, sold elsewhere as the RD350LC, “finally reaches the U.S. market” in 1984. It carried the YPVS power valve, too. According to the Lane Motor Museum, its engine was a water-cooled 347cc two-stroke twin with catalytic converters.

Iconic Motorbike Auctions says the RZ350 was only sold in the States from 1984 to 1985. The house also claims these were the first bikes in the US with catalytic converters. For 1985, buyers could choose red and white or yellow and black, both with Kenny Roberts’ signature on the fairing. In July 2022, Iconic Motorbike Auctions sold a 1984 RZ350 Kenny Roberts for $17,500. The Lane Motor Museum calls the RZ Yamaha’s swan song in the US two-stroke class.

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This article was created with the help of AI and was reviewed and edited by Fast Lane Only editors before publication.