How does oil get to motor in g1 Yamaha golf cart?

There is a gear drive pump behind the clutch. The clutch drives the oil pump. The amount of oil is control ed by a valve on the front of the motor. The more RPM, the more oil is put into the line that goes to the 90 degree elbow from the control to the elbow. Since most of the valves gum up over the years, most people do not use this system, but mix oil in a 40:1 mixture and use it. Had a call today. was not pumping oil, Threw rod, tore up case, destroyed piston and ruined cylinder. Simpler to mix the oil