With a smooth start, the clutches of the clutch are not fully flushed, which allows them to slip a little, and the machine to start the movement smoothly. A smooth start failure may indicate a chaining wear or incorrect adjustment (too large a gap between the disks). However, the disks are not in contact and the machine is not moving forward, and electronics expect speed growth to close the clutches of the clutch. If you press the pedal of the gas, the disks will be instantly closed and there will be a jerk.