The DT-1 was Yamaha’s first off-road motorcycle model. It made its debut in October 1967 at the Yamaha exhibition in the United States. The first generation DT-1 Enduro was released in 1978 and quickly sold 12,000 units.

Indeed, the DT-1 defined a new category of motorcycle known as “dual-sport,” which is designed for both off-road and on-road use. Its introduction sparked an unprecedented off-road riding craze in both the United States and Japan. The versatility and ruggedness of the DT-1 made it a popular choice for riders who wanted to explore various terrains and enjoy both off-road adventures and highway commuting. Its success paved the way for the development of other dual-sport motorcycles and contributed to the growth of the off-road riding community.

The background

The story and development behind the DT-1 actually began in the 1960s on the West Coast of the United States. At that time, an increasing number of riders were seeking excitement and fun in off-road adventures in the vast wilderness of the Western region.

 

During this period, off-road motorcycle riding was gaining popularity, and the Western areas offered plenty of undeveloped natural environments and wild terrains, making it an ideal destination for motorcycle enthusiasts to engage in off-road riding.

 

Noticing this emerging trend, the Japanese motorcycle manufacturer Yamaha recognized the potential of the off-road motorcycle market. To meet the demands of this growing market, Yamaha decided to develop a motorcycle specifically designed for off-road riding.

 

This is the story behind the birth of the DT-1. Yamaha introduced the DT-1, which marked the beginning of a new era in off-road motorcycling, capturing the imagination of riders and contributing to the growth and popularity of off-road riding in the United States and beyond.

In 1967, Yamaha produced the Yamaha YDS3C in the United States. At that time, Yamaha was selling a model designed for off-road riding under the name “TrailMaster.” This model was based on existing off-road motorcycles and equipped with features such as engine guards, reinforced handlebars, and a center-mounted exhaust. However, these were not mature “Trail” models.

 

In 1967, Yamaha released the Trailmaster100 (YL-2C). By the late 1960s, Yamaha’s motorcycle sales were declining in the American market. Market research indicated that while traditional motorcycle sales were slow, the off-road motorcycle market remained untapped.

 

During this time, lightweight and agile two-stroke off-road bikes already existed, but they were produced by a few specialized European manufacturers like Bultaco and Husqvarna, which were both expensive and eccentric.

 

On the contrary, many riders were modifying road motorcycles into off-road bikes by raising the exhaust, adding reinforced handlebars, and installing engine guards. This modification style was called “Scrambler.”

 

As a result, the demand for a purpose-built off-road motorcycle was outlined to Yamaha’s headquarters in Japan from the US. Detailed model samples were sent to Japan. In October 1966, the development of the DT-1 was initiated.

 

At that time, Japan did not even have a defined category for “off-road motorcycles,” so Yamaha sent engineers, product planners, and designers to the United States to observe the actual state of off-road riding and listen to rider requirements. They eventually decided to develop the DT-1 with the following three main objectives:

 

Keep the overall weight of the motorcycle below 100 kg.

Make the bike as narrow as possible for maneuverability on narrow trails.

Maximize the engine torque.

In the winter of 1967, before the public release of the DT-1 in the following year, Yamaha had to determine how many units to produce for the US market. At that time, Yamaha was selling around 4,000 motorcycles per year in the US.

 

However, the enthusiasm for the new model (soon to be known as the “DT-1”) inspired Yamaha to set a sales target of 12,000 units for 1968.

 

The DT-1 proved to be incredibly successful. The first batch of 8,000 units released in 1968 sold out immediately. Production then went into overdrive, and every DT-1 produced was shipped to the United States.

 

Initially developed for export, Yamaha believed that the Japanese market would not have any interest in off-road bikes for the US. However, they were wrong, and Japanese consumers had to wait to satisfy the demand in the US market.

 

The first-generation DT-1 was powered by a single-cylinder 246cc two-stroke engine (18.5hp/6000rpm) with a simple and easy-to-maintain design. Fuel was supplied through a 26mm Mikuni carburetor.

 

Apart from its affordable price (about $700) and reliable quality, the main difference between the DT-1 and other models was Yamaha’s “Autolube” automatic lubrication oil injection system. It ensured the proper oil mixture, improved engine stability, reduced typical two-stroke smoke, and eliminated the need for the owner to manually mix oil.

 

The DT-1 was lightweight with a wheelbase of about 1.36m and a ground clearance of 0.245m. It was equipped with complete lighting equipment and speed and tachometer. It featured 19-inch front and 18-inch rear spoke wheels fitted with specially designed Dunlop dual-purpose tires, suitable for both daily commuting and light off-road use.

 

However, many owners removed all lighting fixtures, modified the fenders for higher clearance, and replaced the tires with ones better suited for muddy terrain to enjoy off-road riding on muddy roads.

 

The success of the DT-1 brought new vitality to the entire industry and directly propelled the growth of the nascent off-road aftermarket and customization businesses in the United States.

 

In the second year of the DT-1’s release, Yamaha offered an official GYT (Genuine Yamaha Tuning) kit, which included chrome-plated cylinder, high-compression cylinder head, new piston, and exhaust, adding 10hp of power for higher-intensity off-road needs.

 

Only five months after the release of the DT-1 in Japan, a DT-1 equipped with the Yamaha GYT kit made its appearance in the All Japan Motorcycle Enduro Championship in 1968 held in Hokkaido. Under the nickname “Suzusan,” the rider Suzuki Tadao won the 250cc category championship with overwhelming dominance, attracting the attention of 20,000 fans.

DT-1 Profile:

Production Years: 1968-1970

Engine Type: Air-cooled, 2-stroke, single-cylinder, 246cc

Starting Method: Kick-start

Bore x Stroke: 70mm x 64mm

Maximum Power: 13.6 kW (18.5 ps) at 6000 rpm

Maximum Torque: 22.6 Nm (2.3 kgf.m) at 5000 rpm

Compression Ratio: 6.4:1

Carburetor: Mikuni 26mm

Transmission: 5-speed

Weight: 105 kg

Top Speed: Approximately 112 km/h

 

More DT-1 models were quickly sold, and Yamaha expanded its product line to introduce various displacements such as 400cc, 360cc, 175cc, 125cc, 100cc, 80cc, and 50cc. All these models upheld the mission of the DT-1, allowing anyone to easily enjoy off-road riding. The DT250 series, in particular, continued production until 1981, during which Yamaha established its unique “Yamaha Trail” product line.

 

With this series, Yamaha solidified its position as a leader in the off-road domain. Other manufacturers followed suit and introduced their own off-road models, leading to a rapid increase in off-road riding enthusiasts worldwide.

 

Undoubtedly, the evolution of the DT series also reflected the evolution of MX-style motorcycles. Starting from the DT-3, the fuel tank underwent a redesign, gradually becoming a slim teardrop-shaped tank at the rear. The exhaust system was rerouted, passing through the cylinder head to the right side and then looping back to the left side for exhaust. The front fender was raised to accommodate the changes.

 

In 1977, the DT received significant improvements, with the rear suspension shifting from the previous dual shocks on both sides to Yamaha’s advanced “Monocross Suspension” with a central shock and a triangular rear swingarm. The exhaust was rerouted to the right side for discharge.

 

(Notably, Yamaha’s groundbreaking Monocross suspension was first introduced on the second-generation YZ250 in 1975 and represented a major revolution in motorcycle suspension technology.)

In 1978, Yamaha introduced the DT250 MX (in white) and DT250 E (in silver-gray). The 1978 models of the DT series featured front suspension with added dust seals, making the details more refined and mature.