Crankcase Ventilation Systems: Operation

The crankcase ventilation system on X1/9 has a large diameter hose from the oil separator to the air filter, and a smaller hose to the intake manifold side of the throttle plate. Crankcase vapors flow through either of the hoses, depending on vacuum at engine loads.

Spider 2000 models have one hose from crankcase to intake housing. Turbo models have a hose to the compressor inlet and the normal manifold fitting is plugged. All crankcase vapors are drawn into the engine through this one hose.