If power strokes cancel out over the motor cycle, then no net energy flow is introduced: free energy gained from one mechanical transition is lost in the other (see Methods, SI section VI B6). This could be realized in molecular form by using non-degenerate binding sites, for example, changing one fumaramide site to a more weakly-binding succinamide unit (Fig. and) with a typical difference in binding energy of 23 kJ mol -1 (pink + symbol, Fig. , equilibrium distribution >99:1) under experimental conditions similar to those used for rotary motor operation. Kinetic asymmetry remains unaltered in this scenario and, correspondingly, the direction of the motor could not be inverted in the simulation. However, our analysis suggests that such a change would be sufficient to effectively stall the motor, if operated under the original experimental conditions, despite the unchanged kinetic asymmetry. The simulations predict that, with power strokes cancelling out, any change from degenerate binding sites lowers the current and efficiency, though a smaller difference would leave the motor functional, albeit less effective. A 3:1 bias 58 (orange × symbol, Fig. ) is predicted to reduce the current by ∼ 20%, rendering a design with non-degenerate binding sites plausible but less effective than a motor with binding sites of equal affinities.