A sickle cutting system is mounted on a header for forward travel over ground having a standing crop thereon and includes a cutter bar with a plurality of knife guards and two sickle bars driven at a phase angle difference where the drive system has a phase difference control component operable to drive the first and second sickle bars at a first phase angle difference typically at or around 180 degrees difference to minimize vibration when no cutting action is occurring and at a second phase angle difference which can be at or around 90 degrees to minimize variations in loading applied to the drive system when the cutting action is taking place.