The start of every new project brings with it an excitement that I never will grow tired of. The research phase always seems to bring some new stories to the surface and seeing the way various bikes were put together at a certain point in time helps fill in the timeline of motorcycle engineering history.

An early promotional shot of the scrambler model. By the time they reached production the battery would be gone in favor of a magneto ignition and the front would be fitted with a 19" front wheel.

The next project here will be a 1960 Yamaha YDS1 scrambler that has already uncovered some great history as the research has gone on for a year now while the bike has waited for its turn to be restored.

  • The YDS1 was a watershed bike for Yamaha as it was their first serious performance motorcycle with a tube type frame and also the bike that would open the door for mass export to other countries. At 250cc the twin cylinder engine was similar to the yd series of the late 1950s but now would sport a five speed gearbox as well as horsepower gains from the previous model. The magazines of the day say that the street version would hold its own against the 650 British four strokes. Although the buying public in America was still leery of the two stroke engine we know in hindsight that would soon change.
  • The YDS1 was offered as a street bike, a road racer called the Asama Racer which was the predecessor to the TD1 road racer or as a scrambler model sold in the U.S. by Cooper motors and named by Frank Cooper the Grand Prix Scrambler Twin. Also many of the parts for the Asama Racer or the GP Scrambler were available over the counter so street version owners could hop up their bike to suit their needs. This hop up kit strategy was an interesting business model and one that Yamaha would continue with from then on. One of the factory riders at that time would later be known for his own Yamaha hop up kits, none other than Taneharu Noguchi.

The Asama Racer was basically a road racer with knobbys attached. This model sported plated cylinder walls that would give owners fits if they didn't follow the break in procedure correctly.

Racing on dirt roads was common in Japan and race bikes were often trimmed out like the Asama racer with low pipes low front fenders and knobby tires. European style scrambling was being noticed by 1960 and so the scrambler was built with a high front fender high handlebars and high expansion chambers. By 1963 the scrambler would be reconfigured into a dirt tracker for the U.S. market and sold as the Ascot Scrambler.

Looking through the eyes of today or even the late 60s the Scrambler doesn’t look like much of a contender but if we look at it from the perspective of 1960 it was quite an achievement as most off road racers in that day were bought as street bikes and converted to dirt racers by their owners. For a manufacturer to produce a scrambles type motorcycle meant that they took every facet of motorcycle sport very serious.

Cooper motors ad from 1960. Note that the scrambler had perfect handling.

Because of a fire at the factory production numbers are not known for these bikes and very few of even the street versions are left today.

More updates will follow as we proceed through this restoration.