Abstract: A rigid motorcycle frame comprises a pair of spaced swingarms attached to a shock absorber which comprises a shock absorber casing or housing pivotally mounted on the swingarms and having a shock absorber rod which is pivotally attached to the motorcycle frame at a point below the housing whereby the movement of the rear wheel of the motorcycle causes the outer housing of the shock absorber to move upwardly relative to the shock absorber, rod which is attached to the motorcycle frame and which is opposite from the normal operation of a shock absorber. The shock absorber may include a spring means and/or hydraulic means to provide the usual resistance provided by a cushioning arrangement. In operation swing arms are moving downwardly the shock absorber moves its mounting points closer together which is different from most shock absorbers which move their mounting points further apart.

Abstract: The first of four adjustments for the shock absorber located between the rear wheel and main frame of a motorcycle is an externally accessible filler-valve enabling the rider to adjust gas pressure in one chamber to vary spring rate and respectively a second adjustment for varying the rate of hydraulic fluid from a main chamber through a main piston to a third chamber by means of a second valve to obtain the desired rate of upper wheel travel, a third adjustment which is an adjustable pressure relief third valve to limit differential pressure between fluid in the main chamber and in the third chamber under conditions of severe impact for the rider to select damping characteristics and a fourth adjustment valve varying fluid flow from a fourth chamber to the third chamber for the rider to adjust damping during extension. Optionally, there is an air cooler chamber around the main chamber and in communication with the carburetor.