Ninja ZX-25R Power And Torque Revealed! More Powerful Than The KTM RC 390

Does it breach the magical 50PS barrier?

  • Engine output has been revealed thanks to a slip-up by exhaust specialist Akrapovic.
  • A new black colour option of the Ninja ZX-25R has also been spotted.
  • Figures mentioned below are measured at the rear wheel, not at the crankshaft.

Months of speculation have finally come to an end with the Kawasaki Ninja ZX-25R’s dyno tested power figure finally being revealed. It feels like Christmas in June, because we’ve also got our hands on the torque output AND we’ve spied a new black colour option for the little Ninja. If you’re wondering where these numbers came from, they were mistakenly let out by Slovenian exhaust system specialist Akrapovic. 

The brand offers two aftermarket exhaust options for the ZX-25R, one of which is street-legal. One of the primary advantages of an aftermarket exhaust system is a bump up in engine output, so Akrapovic put out dyno test results to show how much of an improvement its exhaust systems are compared to the stock bike. These appear to have now been taken down, but not before screenshots were taken. Here are the results:





42PS @ 15,350rpm

43.3PS @ 15,450rpm


20.8Nm @ 12,700rpm

21.5Nm @ 12,500rpm

I’m sure there are more than a couple of disappointed faces reading this, especially since rumours were swirling around about a 50PS or even 60PS power output. But what’s important to note is that these figures are measured at the rear wheel, and not at the crankshaft. It’s not uncommon to see a figure that’s 10 per cent higher at the crankshaft, owing to the transmission losses in the gearbox and chain drive. Taking this into account, power at the crank should cross the 45PS barrier in stock form, making it comfortably more powerful than the already-quite-sprightly KTM RC 390 and even Kawasaki's own Ninja 400.

The Akrapovic column shows the results of a dyno test with the S-K2R2-HAPC street-legal aftermarket exhaust system fitted. Peak output is up by 1.3PS and 0.7Nm, and the maximum gain is actually a healthy 2.5PS at 9800rpm, indicating a strong mid-range. In addition to this, the Akrapovic system is also 4.4kg lighter than the stock bike’s 8.9kg exhaust unit. The S-K2R1-ZC racing exhaust system should result in significantly higher gains, especially when coupled with ECU tweaks.

Engine output isn’t the only piece of news about the little Ninja. We’ve also come across spy shots that show the bike in a glossy black colour scheme that we haven’t seen before. Green is undoubtedly the first colour that comes to mind when picturing a Kawasaki, but black is usually the second, so this colour scheme doesn’t come as too much of a surprise. Besides, we also recently came across possible pricing for the ZX-25R, and it might actually cost more than a KTM 790 Duke! You can read more about that here.

Add Your Comments

Add your comment here
  • View all comments

5 Offers Available