Right,

How the CVH breather system is meant to work (in therory):



Other parts to a KE-Jetronic setup:





I'll annotate one of the shots above but IMO the breather system on an MFI'd RST works as follows

1) The pipe going from the crankcase to the rocker cover (oil cap side) vents the crankcase gasses into the top.
2) On the other side of the rocker cover the outlet goes into a crankcase filter/PCV type of setup (I am assuming the last bit here admittedly).
3) With the smaller bored pipe of the two at certain conditions (idling being one) it will suck the crankcase gasses into the inlet manifold and at light cruising conditions. The other longer and large bored pipe goes to the metering head (this bit I am unsure about admitedly).
4) When the car is on boost the one way valve in the long small bored pipe prevents the crankcase gases from being pressurised from the not positive inlet pressure. In these condition the rocker cover vents more of its crankcase gasses into the metering head.

I am happy to be corrected here (As I said, I am guessing the system works like this).