It was a small check valve in the bottom of each crank chamber.

A float indicator shows the depth of oil in the crank chamber.

Two stroke engines have a tendency to collect unburnt oil and fuel in the bottom of the crank chamber at idle.

Oil is drawn from the sump by the oil pump and delivered to the three inner main bearings and to the other bearings within the crank chamber.

Also included was Suzuki's SRIS (Suzuki Recycle Injection System) which was a method for lowering the visible exhaust smoke by collecting and burning residual oil/gas lying in the bottom of the crank chambers.