This statement is False.
At first sight it would seem logical that your bike has constant acceleration across the speed range, but this is not the case.
More work must be done to push air aside as speed increases, because Aerodynamic Resistance, also known as Drag, increases rapidly with speed. I.E. if speed doubles Drag increases four-fold, and this is also why fuel consumption rises rapidly as speed increases. With increasing Speed, the engine does more and more work to overcome Drag, leaving less available to accelerate the bike: the rate of Acceleration therefore decreases as speed increases.