While the global market for 600cc-class supersport bikes has shrunk to a fraction of its 1990s peak, the last survivors of the category are clinging on and Kawasaki is readying an update for its Ninja ZX-6R that should leapfrog its aging Japanese rivals in terms of technology.
The updated 2024 model has shown up in the EPA’s latest list of approved road-going motorcycles, revealing key details and hinting at more substantial changes when we finally get to see the bike for real. However, the first thing to note is next year’s bike will be less powerful than the version we’ve had from 2019 to 2023. That model, the “ZX636G” to use Kawasaki’s internal coding, already took a slight dip in performance compared to its predecessor, the 2013–2019 “ZX636E,” so the trajectory is clear. In short, meeting international emissions limits is particularly difficult for high-revving, high-powered bikes, and we’re seeing power sacrificed as a result.
While the drop from the “E” to the “G” model was small, going from a peak of 129 hp to 127 hp and retaining the same peak revs of 13,500 rpm, the change for the new bike—two versions are listed, internally dubbed “ZX636J” and “ZX636K—is more substantial. The EPA document rates it at 122 hp, and shows a rev peak of 13,000 rpm that suggests Kawasaki has limited the engine’s outright revs to help meet emissions limits. Since there’s no change to US emissions standards, the alterations are probably due to an effort to meet the latest Euro 5 standards introduced in Europe and elsewhere, which have seen the existing ZX-6R removed from the market all over Europe.
The emissions quoted on the EPA document for the new model are largely similar to the old one, surprisingly showing slight increases in NOx and CO output over the previous model. Under the Euro 5 rules, though, there’s a specific limit on “non-methane hydrocarbons” that’s particularly hard for high-revving bikes to achieve. Essentially, the large valve overlap (the period when the intake valve opens before the exhaust valve closes) required to efficiently replenish the charge in each cylinder at high rpm leads to too much unburned fuel escaping into the exhaust at lower revs. By retuning the ZX-6R’s engine and reducing the outright peak power and revs, it could be addressing that issue without having to go back to the drawing board entirely.
The EPA document also shows a change in final-drive gearing, with longer overall ratios to accommodate the lower-revving engine, but it appears the 2024 bike weighs around the same as the current model (the EPA lists an Equivalent Inertial Mass figure, intended to represent the bike complete with fuel, a rider, and luggage, of 683 pounds, which is unchanged). That suggests there won’t be wholesale alterations to the chassis, but we can expect some more up-to-date styling—no doubt aping the aerodynamics of the latest Ninja ZX-10R—and surely a host of electronics upgrades. A color TFT instrument panel is surely a certainty, and electronics like IMU-assisted cornering ABS, wheelie control, launch control, and stability control are probably the bare minimum to expect on a new sportbike launched as a 2024 model. The fact there are both ZX636J and ZX636K variants could suggest either models with and without ABS or the presence of a higher-spec “RR,” “SE,” or “KRT” edition in next year’s range with more equipment.