For the 1983 model year, the engine of the CX500 Turbo was increased to 673 cc, together with an increase in power. In addition to the increase in displacement, the compression ratio was increased and the maximum boost pressure was lowered thus making for a smoother transition from off-boost to on-boost. The fuel-injection control system was substantially revised for the CX650 Turbo, and the rear shock received an update as well by adding a manually operated damping control mechanism in addition to the "air" pre-load of the previous model.