You got something else going on there then and probably need a new PCV valve and change your oil more often.
A supplied adapter plate for the Weber carb has a brass nipple for hooking up the PCV valve hose to as pictured.
The system consists of a small air intake breather hose mounted in the intake tract before the throttle body, and the PCV valve, which is typically in the intake manifold or the valve cover. Air flow is from the breather before the throttle body, through the crankcase, up the PCV valve and into the intake manifold after the throttle body. It's basically a controlled air leak, with the PCV valve acting as a one-way check valve that has adjustable flow characteristics.
If the PCV valve gets plugged, here's what happens, roughly in order:
1. Excess crankcase pressure begins to back up the engine's breather tube, into the intake air tube upstream of the throttle body
2. Oil begins to be pumped into the air intake tube through the breather hose, upstream of the throttle plate.
3. Oil runs down the intake tube into the throttle body.
4. Oil sludges up the throttle body and throttle plate. Gas pedal starts to get sticky. Airflow reduced. More power loss, possible poor driveability.
5. Oil drips into intake manifold runners. Blue smoke seen out of tailpipe.
6. Breather tube begins to get constricted from oil contamination and airflow is reduced. Crankcase pressure mounts dramatically.
7. Oil pushed past valve guide oil seals. More blue smoke.
8. Dripping on driveway as oil is pushed past seals.