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Minibike power compared at the rear wheel, from VHM dyno sheets, manufacturer curves and our own RaceBox GPS pulls. Filter by class, power, data source, setup and model year in the list.
Everything is shown as rear-wheel power. Every run was measured on a rear-wheel roller dyno, and the electric bikes' figures are rear-wheel figures too, so the chart compares all of them at the rear wheel by default. Most VHM sheets report engine power instead, which is the wheel measurement plus VHM's estimate of drivetrain losses (0.05 hp for every km/h of roller speed, as stated on the 2021 YZ65 sheet); for those runs the chart takes the same estimate back off. The 2018 YZ65 and 2024 KTM 50 SX sheets are already wheel figures. For the YZ65 the two years line up remarkably well either way: the 2018 curve lands almost exactly on the 2021 curve.
Reconstructed RPM. Some sheets plot power against roller speed in km/h instead of RPM. Each sheet lists the RPM at peak power, and speed scales linearly with RPM in one gear, so those runs were converted using that ratio. Torque calculated from the converted curves matches the torque figures printed on the sheets to within about 0.2 Nm, but a small left-right shift is possible.
Units. Dutch and German sheets use pk or PS (metric horsepower); 1 PS is 0.986 hp. Use the units switch to see either.
Curves were traced from YouTube screenshots, so expect errors of roughly ±0.2 hp, a bit more on steep sections. Dyno pick-up at the start of a run and the collapse at the very end have been trimmed. Runs come from different days and possibly different dynos.
An electric bike has no engine RPM to line up against, and it has one gear while the petrol bikes have six, so the fair comparison is power and torque at the rear wheel at each speed. For the petrol bikes, each dyno curve is converted to rear-wheel power by taking off the same 0.05 hp per km/h loss estimate (the 2018 YZ65 already is a wheel figure), then run through every gear. At each speed the chart shows the best gear, which is what a rider shifting perfectly would get. Below the bottom of first gear it assumes the rider slips the clutch at the engine's best torque.
Gearing comes from the owner's manuals. The KTM 65 SX manual lists every ratio (23:75 primary, 14:48 sprockets, 80/100-12 rear tyre), and working through them shows VHM's KTM run was done in 5th gear; 6th would need an impossibly small tyre. The Yamaha YZ65 owner's manual lists the gearbox ratios but not the primary drive ratio, which only appears in the paid service manual, so its runs are assumed to be in 5th as well, matching VHM's method on the KTM. That puts top speed in 6th at about 93 km/h (58 mph) for the 65 SX and 96 to 100 km/h (60 to 62 mph) for the YZ65. The 2021 YZ65 is assumed to share the 2018's stock gearing. The TM 85 uses the full gearing from TM's 2012 manual, since its dyno sheet is in RPM only.
Why the E8 can feel stronger than the petrol bikes. Switch "Petrol bikes" to "Each gear" and the gap is easy to see. A stock 65 only makes big power in a narrow band near the top of each gear; a few mph either side of that band, it's making half as much or less. The E8 delivers most of its power across a wide speed range with no gear to choose, so out of a corner it pulls hard whether or not the rider has picked the perfect gear. The petrol bike also has to get back onto the pipe, open the power valve and spin up its own crank and clutch, while the E8 responds instantly. The "Best gear" view assumes a rider who is always in the right gear and fans the clutch perfectly, which is the petrol bike's ceiling rather than what it usually delivers.
Power-to-weight. The default view divides each bike's rear-wheel power by the weight of bike plus rider, in hp per 100 kg. It reads like a power curve, but a higher line at a given speed means that bike is actually pulling harder, because a heavier bike needs more power to accelerate the same amount. With "Limit to traction" on, the lines sit together wherever grip is the limit.
Acceleration. Choosing "Acceleration" divides each bike's rear-wheel thrust by the weight of bike plus rider, after taking off air drag and rolling resistance on dirt (drag area 0.40 m², rolling coefficient 0.04). Bike weights: YZ65 61 kg and KTM 65 SX about 56 kg with fuel (owner's manuals), RFN E8 58 kg (owner's manual), TM 85 small wheel about 73 kg with fuel (69 kg without). It's the closest single number to how hard each bike feels, but below about 15 mph every one of these bikes can spin the rear tyre or lift the front, so launches are really limited by grip and the rider.
This view compares each engine or electric motor against its own rpm. Petrol engines use engine rpm along the bottom; electric motors top out around 5,700 to 6,000 rpm, so they're drawn against motor rpm on the axis along the top, and the two axes aren't the same scale. Compare the electric curves by shape rather than rpm for rpm. This view can't show how hard a bike pulls from a stop, because a petrol bike's low revs are covered by slipping the clutch; use "How it pulls" for that.
For racing in Australia, the SX-E8 (14/12 wheels) is on Motorcycling Australia's approved list for the 65cc class. MA published a 2026 bulletin (#2084) on performance limits for 65cc-equivalent electric bikes; check it or ask your club for the current figure and where it's measured.