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In my First Ride Review of the 2017 Kawasaki Z125 Pro I mentioned, “the Kawasaki, and its oversquare Single, feels like it has more bottom-end grunt compared to the Honda.” Of course, the Honda in question here is none other than the Grom.

Apparently, my butt dyno needs some calibration. We’ve finally got our hands on a Z125 Pro and the first place we took it to was an actual dyno – the one operated by our friend Chris Redpath of MotoGP Werks – and the result was a little surprising. The baby Z spun the drum to the tune of 8.3 hp at 7800 rpm, and 6.5 lb-ft at 6100 rpm. For comparison, in stock form the Grom puts out 8.7 hp at 6700 rpm and 7.8 lb-ft at 5200 rpm. So not only does the Honda make more power and torque than the Kawasaki, it also pulls off the feat with fewer revs. Advantage Honda. On paper, anyway.

Peak numbers are one thing, but the overall dyno curve is another. The Honda Grom wins on both accounts compared to the Kawasaki Z125 Pro, at least in stock form. The Z has a slight edge once the tach needle reaches the upper limits of its sweep, but that really only matters at the track.

So why was my butt dyno fooled? Gearing is a big factor. The Z125 is geared lower for each of its four gears compared to the Grom. Combining this and the Z’s revvy nature was enough to trick me. Not to mention, discerning between 0.4 hp and 1.3 lb-ft of torque without riding the two back-to-back isn’t easy.

Beyond the peak numbers, it’s clear on the dyno that the Honda shows an advantage throughout the fat part of the rev range, producing significantly more horses and torque (percentage-wise) than the Zed. It isn’t until the 7400 rpm range that the Green Machine ekes out a small advantage, but by this point an upshift should be looming in the horizon.

The Honda Grom has been a sales success, so it’s natural for others to want a piece of that pie.

The Kawasaki likes to rev, which could make it an attractive option for those who plan on taking it to the racetrack, as little bikes like this and the Grom are proving to be popular among mini-bike racing organizations across the country. Once the aftermarket starts finding ways to make the Kawi breathe easier, the baby Z should liven up in the upper revs, as we found with our Project Honda Grom.

Away from the racetrack, in stock trim the dyno numbers would point towards the Honda being the better machine for tooling around town. Its broader spread of power, and especially torque, means you can carry a gear for longer, but in practice the Honda’s gearing compared to the Z might negate that advantage.

Kawasaki’s Z125 Pro is poised to take a big bite from Honda’s pie. Looking at the specs, the two are similar in many ways.

These dyno numbers further prove the Honda and the Kawi are so closely aligned. They weigh practically the same at 225 lbs, make similar power, and are within $200 of each other. Of course, we won’t know for sure how the two bikes will stack up side-by-side until we put them against each other. We’re working on that now, but in the meantime feel free to chew over the dyno numbers above and speculate on which you think the winner would be in the comments below.