Yamaha turned its attention to outboard engines as a new product category to add to its motorcycle business and the P-7 was the first outboard engine model Yamaha developed in this endeavor. Based on small engines originally developed for motorcycles, this model shared several parts with Yamaha’s motorcycles and had specifications and performance that made it capable in both pleasure boating and commercial fishing use; like a transmission with forward and reverse gears and the capability of being able to switch between gasoline or kerosene fuel.
The development team for the P-7 consisted of just two engineers. It was truly a case of relying on trial and error every step of the way. The tests would run until something broke, then the engine was examined and a way was found to improve it. President Genichi Kawakami demonstrated a strong commitment to the manufacturing of outboard engines, making frequent visits to the development site to monitor their progress. Finally, in July 1960, Yamaha put its first outboard engine on the market - the P-7 - with a production plan of 200 units per month. This marked the beginning of Yamaha’s history with outboard engines, despite a noisy engine that vibrated considerably.
Engine
It was an air-cooled, 2-stroke, 123 cc model with seven horsepower.
It wasn’t until a year after the introduction of the P-7, that Yamaha outboard engines began to be recognized and accepted on the market with the release of the second model, the P-3. The P-3 was developed and refined based on feedback directly from the market. It had been developed precisely for the needs of the growing commercial-use market, where 3 hp engines were the de facto standard. Having been developed with a focus on engine durability and corrosion resistance, the P-3 was especially resistant to abrasion.
This was thanks to the exclusively developed aluminum alloy is used, which contained silicon. It was also the first domestic outboard engine to use die-cast parts, helping achieve a lighter and more compact design. Special attention was also given to making the engine easy to start and operate. The fuel tank of the P-3 was designed by female staff members, which was unusual in those days but met one of Yamaha’s shared values: innovation.
At that time, red outboard engines were quite popular and the coastal waters were truly a sea of red. One year after the launch of the P-3, however, waters off saw a conspicuous increase in “yellow hats,” as Yamaha outboard engines soundly infiltrated Japan’s coasts.
Engine
The engine was powered by a 63cc air-cooled single-cylinder 3 hp engine. It was made of aluminum alloy which contained silicon.
DT-1’s development was initiated after receiving information that road sports bikes did not sell very well, but what was gaining in popularity were models that could be freely ridden; not only on public roads, but also through meadows and in the mountains. This led Yamaha to try building such a type of motorcycle for the first time. The idea of a new type of motorcycle that would combine the features of both motocross and trial bikes and could be ridden on normal roads and off-road had puzzled the development and testing manager at Yamaha’s headquarters.
However, it was precisely that innovation that built the success of the DT-1. The model became such a major seller, moving at a rate of 500–600 units a month, that it practically created the market for trail bikes, which became a major category of motorcycles.
Engine / Frame
The DT-1 is a 250cc single-cylinder model. To make it suitable for a mass-production model, the DT-1’s engine was a redesign based on the Yamaha YX26’s, a true motocross bike that had won the All-Japan Motocross Championship in May 1967. Following its ‘mother’ model, the bore x stroke of the DT-1 was the same 70 mm × 64 mm. For the frame, high-tensile steel pipe was used, as well as a robust chassis strong enough for a production model.
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