First in the dirt
Brad Powell's 1968 Yamaha DT-1.
Years produced: 1968-1971
Claimed power: 18hp @ 6,000rpm
Top speed: 70mph (approx.)
Engine type: 246cc, 2-stroke, air-cooled single
Weight (dry): 105kg (231lbs)
Price then: $520 (est.)
Price now: $1,500 - $4,500
1968 was quite a year: History buffs will likely remember the escalating war in Vietnam or that Martin Luther King Jr. and Robert Kennedy were assassinated that fateful year. But gearheads of a certain age remember 1968 as the year the Yamaha DT-1 hit the scene and changed motorcycling forever.
Prior to the release of the Yamaha DT-1, reliable, reasonably powerful and inexpensive dirt bikes simply didn’t exist. The various — mostly British — scramblers on the market tended to be big and heavy, and while companies like Greeves, Montesa and Penton offered purpose-built dirt bikes, they were expensive and quirky. The DT-1 changed all that.
The Yamaha DT-1 was a solid, inexpensive bike you could ride to the track and then run with the best purpose-built dirt bikes of the day once you got there. And even if you weren’t a racer, it was a great compromise bike that could handle almost any trail you threw at it — and still get you safely home at the end of the day.
A fresh idea
Looking back, it seems simple enough: Build a lightweight but strong frame, put some moderately-long-travel suspension under it, add some dual-sport tires, throw in a reliable and reasonably powerful engine, add the street legal bits, and then sell it for a good deal less than the nearest true dirt bike. Presto, instant hit.
Up until that point, nobody had figured that out, and with the introduction of the Yamaha DT-1, Yamaha essentially defined a new market for motorcycles. Savvy research had shown there was a market for this type of bike in the U.S., but even Yamaha was surprised by the enthusiasm American buyers showed for its new bike: The initial 12,000 production run sold out quickly, so Yamaha ramped up production immediately, selling thousands of its little dirt bike while the rest of the industry played catch-up.
Although the DT-1 was a bike that was happy getting dirty, it also played a big role in cleaning up motorcycling’s image. In the late Sixties, motorcyclists were still often seen as outlaws. The DT-1, in helping to popularize dirt biking, showed motorcycling as a wholesome, athletic affair, making it much more acceptable to the general public.
More than the sum…
No individual piece of the Yamaha DT-1 was really revolutionary. The DT-1’s steel frame was a standard single-backbone, double-cradle design, although the use of tubular instead of stamped steel was still somewhat advanced for a Japanese bike. The wheelbase was a nimble-without-being-squirrelly 53.5 inches, with rear suspension duties handled by a rectangular-section steel swingarm and dual shocks with four inches of travel. In the front, standard telescopic forks offered six inches of travel. The aftermarket quickly geared up to offer suspension upgrades for both ends of the bike, improving damping characteristics and increasing travel. In fact, the DT-1 spawned a veritable cottage industry of aftermarket parts.
The bike rode on an 18-inch diameter steel wire-spoke wheel with a drum brake in the rear, and a 19-inch wheel in the front, also with a drum brake. Braking was barely adequate by today’s standards, but was decent for its day. From the factory, the rims were wrapped with specially-designed Dunlop dual-purpose block-tread tires (4 inches wide in the rear, 3.25 inches for the front) that were adequate for light-duty trail work, but were immediately traded for true knobbies for serious dirt duty.
The heart of the Yamaha DT-1 was a moderately powerful (18hp @ 6,000rpm) and reliable 2-stroke, 246cc single. Fuel was fed through a 26mm Mikuni carburetor and spent fumes traveled through an upswept exhaust pipe. Spark was provided by a standard magneto, and starting was by kick only. Other than acceptable power and solid reliability, the main difference between the DT-1’s engine and other bikes was Yamaha’s Autolube oil-injection system, which most certainly helped it appeal to new motorcyclists who didn’t want to deal with premixing fuel and oil. The Autolube system also helped with reliability and reduced the typical 2-stroke smoke by ensuring proper oil mixture. Yamaha also focused on making the engine as narrow and light as possible to keep the bike nimble.
The bike came with a speedometer and a slightly smaller tachometer, as well as full lighting equipment to make it street legal. Many owners removed all this street fare when they took delivery of their bikes, rode the heck out of them in the dirt for a couple of years, then bolted everything back on when it was time to sell. The low-mounted aluminum front fender was often scrapped for an aftermarket high-mounted plastic unit for more serious off-road use.
Overall the styling was subdued. The first year’s pearl-white tank and headlight nacelle were replaced in later years by brighter colors. Fenders, fork sliders and engine were all gray. Chrome wheels, exhaust heat shield, handlebars and headlight bezel brightened things up a bit, and the candy-red tank badge gave the otherwise almost monochrome bike a splash of color. Although a bit bland by today’s standards, people who grew up around DT-1s still think of them as how a classic bike should look.
And that’s a huge part of the magic of the Yamaha DT-1 and the many siblings — bigger and smaller — it spawned.
These bikes seared an image of what a bike should be into the minds of thousands of youngsters in the Seventies — an image they still hold strong today. MC
Special thanks to Brad Powell for supplying our photo bike.