Kawasaki A1 250 Samurai

The Kawasaki W1 did not sell as expected, because all rival bikes were still faster, lighter and had better steering. Kawasaki developed the lighter A1 Samurai in 1967. The A1 took center stage as a high-performance machine, with approximately 80ps per liter. It was quickly followed by a larger-bore model, the Kawasaki A7 Avenger which shared most of the Samurai components except the motor.

The A1SS Samurai has a crossover dual exhaust mounted on the left side and just below the seat. Other than exhaust system, there were no other changes between the standard A1 and A1SS.

The engine was a unique straight twin, two-stroke, air-cooled, oil-injected, dual rotary disc valve. The engine's ignition air supply began in an air filter canister below the seat and was pulled through a large plenum chamber just above the transmission and behind the cylinder head then downward into the two internal passages leading to the carburetor housing feeding the carburetors. The A1 had two Mikuni carburetors located on the engine's left and right sides and inline with the crankshaft. The carburetors were enclosed and protected from the elements by carburetor covers fixed to the crankcase. Inboard of each carburetor, and supporting each carburetor, was the disc cover. The rotary disc valve was housed inboard of that cover. The A1 Samurai motor was lubricated by the Superlube system, with 2-stroke oil directly injected in the intake tract. Previously equipped with points, the ignition system was equipped in 1969 with a Capacitor discharge ignition including thyristor-based switching system then increased the voltage to between 25,000 and 30,000 volts reducing the unburned fuel mixture within the cylinders.[1]

This combination of displacement (247cc), CDI system, and rotary discs produced 31 hp (23.1 KW) @ 8000 RPM gave the Samurai a power-to-weight ratio of 1 horsepower per 11 pounds of weight, a 0-60 mph of 6.6 second,[citation needed] making the Samurai as fast or faster than production competitors in its class.

Source wikipedia

Overview

Early on, Kawasaki executives quickly learned that customers wanted far more than just getting from Point A to Point B on a fun little machine. The open roads and huge continent invited bigger bikes with more performance, much more. So, in a brazen move for the time, a twin-cylinder, rotary-valve two-stroke motorcycle called the A1 Samurai was created, soon to be followed by the larger A7 Avenger.

Both bikes were specifically designed for the United States market under the leadership of the president of American Kawasaki Motorcycle Corp., Royozo Iwaki, but before launch they needed to be proven on America’s roads. In February 1966 a factory engineer from Kawasaki Heavy Industries, Ltd. arrived with a Samurai prototype, and American Larry Beall, a future Kawasaki sponsored racer, signed on as test rider. With a budget of just USD2,000, the test ran from Oklahoma City to New Mexico, with most of the route in Texas.

The trip was successful, and within months A1 production bikes – along with Kawasaki’s first production road racer, the A1R, began arriving at dealers. They were fast. Their performance matched that of the British bikes twice their size. Word of this performance began to spread among dealers, customers and the press. When Jim Deehan won the Open Production race at Willow Springs Raceway aboard an early A1 Samurai – the first road race for a Kawasaki vehicle –the floodgates of interest in the Kawasaki brand burst open. Kawasaki’s unique brand of daring, in-your-face attitude had arrived.