Air cleaner assembly fresh air to breather

...Your set-up is Correct...From Idle to WOT, the 'Vapor' Flow moves Back and Forth, reversing Direction. It's all in the Design, Eliminates Breathers and keeps the Engine Cleaner, in  My View.

MJ

I have my PCV to carb on the left valve cover and my breather to the underside of my K&N air filter.  I also T connected the tank connection that went to the old charcoal canister which was dumped long ago.  From the web, here is why I did that:

"There is no difference between a breather, and the connection to the air filter assembly, both are filtered air inlets to the engine to allow air flow through the crankcase. The PCV pulls air out of one side of the engine, replacement (filtered) air comes through either a push in breather or the connector tube to the air filter assembly. Functionally identical"

@Dan A. posted:

.  Would this "inside"  attachment position be under vacuum and in fact suck out air from the filler/breather cap and work against the PCV valve?

IF there is significant vacuum inside the air filter, you need a new/clean filter.

I have never measured / nor recall published info, but I would expect only a few inches of WATER at WOT.  where as the intake vacuum is inches of MECURY (Hg to H20 is ~14:1).   i would expect the pressure drop caused by the snorkel itself would be more than inside an open aftermarket cleaner

Air at the air cleaner is effectively at atmospheric pressure.  The movement of the piston creates a partial vacuum of which atmospheric pressure air flows into.

@panterapatt posted:

Air at the air cleaner is effectively at atmospheric pressure.  The movement of the piston creates a partial vacuum of which atmospheric pressure air flows into.

...actually...there is No such thing as a 'Vacuum'. It's a term used to describe the 'Absence of Atmospheric Pressure'. This is a Negative Pressure, that can be worked in a Mathematical Formula, where as a 'Vacuum' is '0' Zero, and will Only produce Zero when tried to work in a Formula. Make Sense??

The Piston does Not Create a Vacuum. "The Piston Creates a VOID, that is filled by the rushing in of Atmospheric Pressure. You were Half Correct.

Interestingly Enough is the AP at Sea Level is Approximately 14.7 PSIG, which coincides Exactly with the 'Perfect' Stochiometric Ratio of Air to Fuel at 14.7:1

Further, a Pressure Gauge held in Your Hand, Not hooked up to Anything....Should be Reading 14.7 PSIG, from the existing AP.

and it would, if in a Bell Jar, with the INLET from OUTSIDE of the Jar, Open to AP...and INSIDE the jar was a 'Absence of Atmospheric Pressure', (Near) Zero! The Gauge would read 14.7 PSI at Sea-Level.

MJ