To properly set the cleaner and oil head assemblies, you must first check the tension of the oil head timing belts. This belt should not run loose, but not overly tight either. With the oil head all the way over to one side, press down in the middle of the belt and you should feel some resistance when the belt reaches the head bar. If an adjustment is needs to be made, loosen the four screws that mount the head drive motor to the bracket and slide the motor until the correct tension is found and tighten the motor bracket screws.