The Kawasaki GPz1100 B1 and B2 are motorcycles that were manufactured by Kawasaki in 1981 and 1982 respectively. Both models featured a four-cylinder, two-valve air-cooled engine design with a capacity of 1,089 cc producing 108 bhp (81 kW) in the B1 and 109 bhp (81 kW) in the B2. This engine was an evolution of the powerplant used in the previous Kz1000 series, itself descended from the Z1. In 1983 the GPz1100 was completely revamped in both cosmetic styling, suspension and updated engine. The model number changed to ZX1100A1.