For some time, we’ve been left to speculate how much power Kawasaki’s upcoming ZX-25R four-cylinder screamer can produce. Kawasaki has done everything from show off the bike on the track, on the dyno, and through teaser videos. Yet none of these have revealed the actual performance figures, leaving us to simply make an educated guess.

Leaked: Kawasaki ZX-25R produces 45 hp image

Now we have a more precise figure. This has been unintentionally leaked by Akrapovic which has been testing the upcoming model in order to produce aftermarket exhaust systems for it.

Akrapovic had put a ZX-25R on a dynamometer to measure the performance gains its upcoming exhaust system can provide over the stock system. Posted on their website, it appears the ZX-25R produces 42.01PS at 15,350 rpm and 20.8 Nm of torque at 12,700rpm. These are figures measured at the wheel using a dynamometer.

Power measured at the wheel is usually lower than the indicated power figure due to losses when the power is transferred from the engine crank to the chain drive via gearing. Usually, the difference from the indicated figure (measured at the crank) is around 10 percent in motorcycles. If you take that into account, the indicated peak power of the ZX-25R is likely to be about 46 PS (45 Hp) at the crank.

Leaked: Kawasaki ZX-25R produces 45 hp image

It may not seem like much, but it’s certainly significant given it’s just a 250cc engine. For comparison, KTM’s 390 Duke produces 43.5 PS at 9,000 rpm and 37-Nm at 7,000 rpm at the crank. Yamaha’s 321cc R3 produces 41 hp and 30 Nm of torque. Honda’s CBR500R produces 46.4 hp and 43.1 Nm of torque. Kawasaki’s own Ninja 400 makes 49 hp and 38 Nm of torque. As you can see from these comparisons, the ZX-25R has performance closer to 400cc motorcycles.

As for Akrapovic, the exhaust it is producing for the ZX-25R will increase power and torque by 2.44 PS and 1.8 Nm. Its exhaust is also lighter by 4.4 kg than the stock unit’s incredibly heavy 8.9 kg weight.

Bear in mind that while the highly anticipated ZX-25R’s performance figures may seem impressive, it’s not without its caveats. First of all, the bike may be considerably heavier than other 250cc motorcycles in its class. After all, it has 2-3 more cylinders than most of its competition.

Second, it may consume a lot more fuel. A typical 250cc single-cylinder or parallel twin returns 30-40 km/L. This ZX-25R may only be able to return 25-30 km/L at best.

Finally, it’s not likely to be cheap. The ZX-25R may have 400cc performance figures, but it may be priced close to if not equal to a 400cc big bike. Creating a small 250cc engine isn’t easy, and some of the cost of that research and development will be passed along to the consumer.

Still, it’s a very exciting bike to look forward to.