Kawasaki Ninja ZX-4R

The Kawasaki Ninja ZX-4R is a 399 cc sports bike that Japanese manufacturer Kawasaki introduced in 2023, first shown in the United States, Asia and Australia in February of that year. It is notable as the only modern road sports bike with an in-line four-cylinder engine of such small displacement, a 16-valve DOHC unit with four injectors that delivers about 57 kW and 42 Nm of torque and revs to 16,000 rpm, with ram air raising output to about 80 horsepower at speed. It comes in three versions: the base ZX-4R, the SE with team-inspired colours, quick shifter, smoked screen and frame protectors, and the top ZX-4RR with an oversized rear shock. The diamond-shaped steel trellis frame is partly derived from the smaller ZX-25R, the rear suspension partly from the ZX-10R, and the front brakes are twin 290 mm discs with monobloc radial calipers.