first is my 'disclaimer'
I am not an expert in internal combustion engines, I know very little actually
here's my thinking on this
we all know that the engine breathes, and as pressure builds up in the crank case, that pressure has to be released
since the pressure is over fluid (oil) it will have oil mist in the air, also inside the engine is moisture
so what you have in the way of material that is being vented is oil droplets/mist and water vapor that condenses and becomes droplets
normally you don't see any of this because it is routed back to your intake
some bikes, for unknown reasons, have more of this material in the vented air than other bikes
for those that do, and are still stock, they experience a dripping of this material out of the bottom of their air cleaner box, and/or blown back on the side panels and the riders leg.
As you know, I've decided not to vent this back to the intake on my bike .... if you ever seen what is drained out of a catch can, you probably would not run yours back to the intake any longer either
since there is more water content in this matter than oil, I would not vent it back to the oil tank, water in your oil is not a good thing as we all know .. also I'm not sure what effects it might have on the overall operation of the engine ... somehow it doesn't seem like you'd want to vent pressure into the engine, we're already providing a way to let it out
I ran the vents to a catch can because
1) running it to a hose open to the ground leaves the matter to be blown around on the bike and still make a mess
2) catching it in a can provides me with a means to dump it when and where I want to
I used this particular catch can because
1) it has a petcock valve on it. Flip the valve open, the can drains.... nothing on you, nothing on the bike, close the valve and be on your way.
2) it holds 1 pint of material ... so I don't expect that it will become full if I should forget to dump it every time I gas up .... if the can becomes full, the material will be expelled out the filter on the top of the can. It would make a mess, like before ... hurt nothing .... drain the can, clean the filter and the bike and Ride On .....
Is it as 'neat n clean' looking as stock .... well, no, but to me it's worth it and it's not 'ugly' ......
If anyone really notices it, it just gives us something else to yak about

It's not for everyone, but then what is ?