Interestingly, the CARB executive orders demonstrate that the ZX-4R emits lower emissions than the twin-cylinder variants, although delivering higher performance. The Z400 and Ninja 400 are approved to emit 0.3 g/km of hydrocarbons and 4 g/km of CO2, while the ZX-4R emits 0.1 g/km of hydrocarbons and 0.4 g/km of CO2.
The ZX400SP is listed in the CARB order, but the ZX400PP is not. It’s worth noting that the “SP” designation does not always signify a higher-end model. The “P” at the end represents the 2023 model year, while the letter before that merely denotes a different model version.
