Yes, we can accelerate the motorcycle without putting higher petrol input rate into the engine, as acceleration means change

in velocity per time. Thus, we can infer that one can even change acceleration by changing its direction by maintaining its magnitude constant since we know that acceleration is a vector quantity. So, by maintaining the petrol input rate constant if the motorcycle moving in a circular path is given a turn along the arc of circular path, it will have an acceleration towards the center of the circular path, called as Centripetal acceleration.