CLASSIC MOTOCROSS IRON: 1963 YAMAHA 250 ASCOT SCRAMBLER
Southern California’s Ascot Park was the hotbed of flat-track racing in the western United States in the 1960s and 1970s. AMA rules required first-year professional riders to compete on 250cc machines until they made enough advancement points to move up to the Amateur class. Amateurs and Experts rode machines up to 750cc (four-stroke twins or 500cc four-stroke singles).
The top prospects in the 250 Novice class often showed up with twin-cylinder Yamaha TD1 engines in custom frames built by Trackmaster and Redline. Yamaha decided to seize the opportunity and publicity from winning races by introducing the Ascot Scrambler. This limited-production model was derived from the street-going YDS2 model (with aluminum cylinders similar to the TD1 road racer model). The carburetors were 24mm Mikunis—larger than the 22mm units on the S2, but smaller than the 1-1/16-inch Amals that came standard on the TD1. The Ascot Scrambler had chrome expansion chambers and TD1 brakes.
Sales were brisk, but owners soon found out that the handling was not on par with the…