Could The Kawasaki Ninja ZX-25R Make 50PS From 250cc?

Long before the Kawasaki Ninja ZX-25R was unveiled at the 2019 Tokyo Motor Show, there were already rumours floating around about the bike’s power output.

Estimates ranged from 40PS to a scarcely believable 60PS. Now, we’ve come across some images that could give us a more realistic idea of the bike’s performance figures.

Pictures of the 25R’s instrument cluster show a stratospheric 17,000rpm redline! Implementing an inline-four configuration at this displacement range means tiny cylinder bores, pistons, con rods and so on, which means very low rotational inertia. Each piston’s stroke length will also be similarly miniscule, and these factors combine together to make this astronomical redline possible.

So now that we know how high the 250cc motor can rev, we’re in a slightly better position to estimate the power output. It’s reasonable to assume that peak power will arrive approximately 1000rpm before the redline, at around 16,000rpm.

Considering the motor’s displacement and configuration, it’s fair to assume a peak torque figure of around 24-25Nm, but this will be produced earlier in the rev range. At 16,000rpm, torque will have trailed off a little and we can presume that the motor is producing about 20-22Nm.

Putting these figures into some simple formulae, we arrive at peak power output figures in the range of 45.5PS to 50PS. Not quite as high as the 60PS that some were predicting, but that’s still a very, very healthy amount of power for a 250cc motor.

If these calculations are accurate, it would mean that the ZX-25R is even more powerful than the much larger Ninja 400. In fact, at 50PS, it would only be 18PS down on the Ninja 650! It isn’t surprising, then, that Kawasaki has equipped the 25R with electronic aids like traction control.

Also Read: Here’s What Makes The Kawasaki ZX-25R Tick

While all this sounds very exciting, we must remind ourselves that it is speculative, and we can’t be sure of anything until Kawasaki releases official figures and even more so once the bike is put on a dyno. Until then, we just have to keep our fingers crossed and wait.

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