Bikes You Should Know appears weekly as part of Two Wheel Tuesdays. Since Hooniverse primarily caters to automotive enthusiasts, this column focuses on historically or culturally significant motorcycles that are likely to interest a non-riding audience.

With certain motorcycles in this series, the casual observer can easily understand why they were were revolutionary just by looking at them, even with modern eyes. It is harder to grasp exactly what made the DT-1 such a milestone without a bit of explanation. After all, there were dirt bikes and “street scramblers” before 1968, and gobs of small, street-legal dirt bikes have come along since. But the DT-1 is the reason why “dual-purpose” and “dual sport” have become common terms. It was the first bike that was designed to be equally at home on the street, on a motocross course, or casually exploring dirt trails. And people went crazy for it.

THE BACKSTORY

Riding motorcycles in the dirt is as old a practice as riding motorcycles. In fact, early in their history, finding a smooth, paved road was the exception rather than the norm. As motorcycle writer Lane Campbell explained, “…there were just bikes. I mean, you had a motorcycle; you rode it wherever the spirit led — on road or off.” At some point, however, “dirt bike” became a term that differentiated certain machines by both construction and intent. By the mid 1960s, there were plenty of “dirt bikes,” but they were typically revised versions of street bikes: just as large, with the same frame, engine and suspension. Dirt versions simply had more tucked-in exhausts, wider handlebars, and block-tread tires. Factory-built competition versions typically dispensed with street-legal equipment such as lights and instruments. Throughout the ’60s, “scrambling” (which was early motocross racing, basically) and “enduro” competition became increasingly popular in the United States. Most of the “street scramblers” being sold at the time were just high-piped street bikes, woefully under-equipped for competitive racing. The successful racing bikes for sale were either expensive, unreliable, high-strung two-strokes or huge, heavy twins that were a handful in the dirt. Yamaha recognized that, and designed a clean-sheet product that was intended from the start to be a competition-ready dirt racer that was also suitable for street use.

WHAT HAPPENED

When Yamaha introduced the 250cc DT-1 in late 1967, it wasn’t totally revolutionary. It looked a lot like the bikes Bultaco and CZ were building in Europe: a lightweight two-stroke single in a compact frame with dirt tires and plenty of ground clearance. Unlike them, the DT-1 had auto-lube injection, and a tractable engine that was easy for novice riders to get the most out of. But while DT-1 was remarkably practical and reliable as everyday transportation all week long, it was competitive enough to win races on the weekend. And unlike the bikes it was stealing podium spots from, it was affordable. While others used the same ingredients, Yamaha had come up with the perfect recipe. The DT-1 began selling in unexpectedly huge numbers as soon as it hit the showroom floor. Yamaha expected to sell 12,000 that first year; they ended up selling 50,000. That success continued unabated for years. Yamaha fueled the fire by introducing “GYT-kits” (Genuine Yamaha Tuning), factory-supplied hop-up kits for serious racers that turned the somewhat tame engine into a real fire-breather that could wrestle the holeshot away from bikes twice its size.

WHY IT’S SIGNIFICANT

In the ’70s and ’80s, dual-purpose bikes were widely known as “enduros,” even though the vast majority of them would never participate in a competitive enduro event. Why? Because Yamaha had put the word “Enduro” on the flanks of the DT-1, and the DT was synonymous with dirt bikes you could ride on the street. European makers such as Bultaco saw their sales to casual dual-purpose riders dry up overnight, solidifying the Japanese manufacturers’ market share. The DT-1 forced Honda to up their game, replacing the CL street scramblers they had been selling with the more hardcore SL and later XL series. Yamaha themselves would introduce a whole range of DT two strokes, from 50cc to 400cc, renaming the DT-1 the DT250 in the process. A whole generation’s introduction to motorcycling was on street-legal trail bikes. That might seem self-evident, but it might have been different; the DT-1 was the match that ignited the whole ’70s trail bike boom. The fact that the DT-1 looks somewhat ordinary when one looks at it today simply illustrates how totally it infiltrated the motorcycle scene throughout late ’60s and ’70s, and how dramatically it changed the market. IMAGE CREDITS: Yamaha Motor Corp., Cycle World Magazine/Bonnier Corp.