The only way to test them would be to build yourself a flow rig.
They rarely go wrong to the point they would cause issues like that, it would have completely failed and you would have no oil going back to the dry sump tank - or you would be suffering from oil surge.
Wet sump versions of these engines run and do not suffer with enough excess crankcase to cause issues.
What makes you say it is excessive? Is the engine blowing out oil?
At idle there is quite a bit of pressure coming out of the PCV breather location.
Catch can fills 50-75% every 20 min session.
In this picture of a Hayabusa dry sump system it shows a -12 feed from the can and a -12 return to the tank. My car has a -12 feed and a -10 return to the tank. Makes me also wonder if the pump is incapable of pumping enough oil back with the smaller return.
Has this a problem that has just started or been there as long as you have owned the car?
AN12 or even AN16 feed on later cars with an AN10 return is standard on all Radical's so no concern there.
I assume you are setting the oil level correctly and not over filling it? Ensuring that you run it up and pick up the revs before checking the oil level?
How is your breather piped up? On a standard Radical set up the engine breather goes to the dry sump tank and then a breather from the top of the dry sump tank to your catch can.
Have you tried a leak down test? How many hours are on the engine?
Has this a problem that has just started or been there as long as you have owned the car? It has been happening since I bought the car 5 years ago.
AN12 or even AN16 feed on later cars with an AN10 return is standard on all Radical's so no concern there.
I assume you are setting the oil level correctly and not over filling it? Ensuring that you run it up and pick up the revs before checking the oil level? Correct, the oil needs to be 6" from the bottom of the tank to not spew out, approx 2L of oil. Anything more than that and the puking occurs.
How is your breather piped up? On a standard Radical set up the engine breather goes to the dry sump tank and then a breather from the top of the dry sump tank to your catch can. I have a gen 1 oil tank, the breather originally was setup like this picture below. I cap'd the one going to the catch can and added a line from the top of the tank going to the catch can. This helped big time, but the catch can still filling up about 50% each session.
Have you tried a leak down test? How many hours are on the engine? I did not continue on with a leak down test since the compression numbers were so good. The engine has approximately 41 hours and is a 1340.
