Today, we use the term “crossover” for vehicles that ride like a car on roads but have the rugged utility of a truck. But the term could be applied to a breed of motorcycles as well. The grueling motorcycle scramble races of the early 20th century, such as Big Bear and Barstow-to-Vegas, created a new market for off-road motorcycles that offered enough power for extended desert treks—while capable of road trips on American highways.
Yamaha was the leader of the pack with a series of Enduros: a new breed of affordable performance bike inspired by desert scrambles but geared towards adventure-bound baby boomers who were coming of age at the time. The Yamaha bikes gave British competitors including Triumph, BSA, and Norton a run for the money. A prime example is the 1973 Yamaha RT3 360 Enduro now listed on eBay. It’s the last of a model series that began with the 1968 Yamaha DT-1, whose single cylinder two-stroke engine was as powerful as it was reliable.
Since Enduros were thinly disguised race bikes, most didn’t survive. Two-stroke engines are known for power more than durability. The fact that the ’73 RT3 360 in the listing is all-original with matching engine and frame numbers makes it extremely rare.
According to the bike’s current owner, the odometer registers 7,342 miles on an engine which to this day has never been rebuilt. The gas and oil tanks are dent-free and the tires are also original. The owner is including the original keys, tool kit, and owner’s manual in the sale.
Seeds of Yamaha’s Enduro bikes are evident in a 1965 model called the Big Bear Scrambler, named after the brutal 150-mile desert race that started in California’s Lucerne Valley and dominated by the legendary Bud Ekins who won the race six times. Also-known as the Yamaha YDS-3C, the Big Bear Scrambler came equipped from the factory with skid plates, high exhaust pipes, and braced handlebars—all protective measures against damage on the trails.
Two-stroke engines were the secret sauce behind the Yamahas DT-Series Enduro bikes’ combination of power and agility. Two-stroke blocks are lighter and faster than four-stroke designs because the spark plugs fire once every revolution as opposed to every other revolution. They also vibrate more, hence the durability issues.
The Yamaha DT-1, introduced in 1968, came with a single-cylinder 250cc engine based on a motocross design. It wasn’t the smoothest running engine of the time, nor the easiest to kick start, but once it got going, it went like spit.
By the early 1970s, Yamaha’s Enduros had grown in displacement and power. While the RT-series bikes performed well on paved roads, the geometry didn’t work as well off-road. The 1973 RT3 360 was the last model to use a modified version of the frame first introduced on the DT-1. The following year Yamaha’s Enduro bikes got a new frame design with more ground clearance, a longer wheelbase, and more wheel-travel for better handling off-road. In 1975 Yamaha introduced a larger 397cc block for its DT 400 series, replacing the 351cc engine in the 360s.
Among the early models that Yamaha produced, the Enduros of the late 1960s and early 70s were the most significant, transforming the manufacturer from bit player to a major contender in the US market. For motorcycle riders with a sense of adventure, there was nothing better than a Yamaha Enduro.