Harley-Davidson Fat Boy vs Yuki Hammer 125

The Harley-Davidson Fat Boy (2025) and the Yuki Hammer 125 (2026) are compared with the same Moto Kıyas physics model under identical conditions: flat dry asphalt, no wind, a 75 kg rider and no passenger. The Harley-Davidson Fat Boy is a cruiser with 1,923 cc, 103.3 hp and 315 kg; the Yuki Hammer 125 is a naked bike with 124 cc, 9.1 hp and unlisted weight. Power-to-weight with the rider: 264.8 hp/ton versus 47.6 hp/ton. On this measure the Harley-Davidson Fat Boy is 456% ahead.

0-100 km/h (speedometer): Harley-Davidson Fat Boy 3.54 s, Yuki Hammer 125 not reached (top simulated speed 69 km/h). In the 60-0 km/h brake test, braking distance without the 0.3 s reaction time is 17.7 m for the Harley-Davidson Fat Boy (ABS unknown, class assumption: no ABS) and 17.3 m for the Yuki Hammer 125 (ABS unknown, class assumption: no ABS). The Yuki Hammer 125 stops 0.4 m shorter. The standard 60-0 test is used because one calculated top speed is below 110 km/h. Calculated top speed: 201 km/h (estimated from power and drag) versus 83 km/h (manufacturer claim).

All values are an estimated simulation, not road-test measurements. Technical data comes from the sources listed below; the model uses class-average calibration (no accepted model-specific road test) for both. Open the interactive app (currently in Turkish) to watch the run side by side and change the load.