Questions about flapper and "element assembly" diaphragm

[TheRadBaron]

So I've finally got the wife's Vision running well enough to ride.  I'm still working on fine-tuning it but I'll address that in a different post if necessary.  I just have a few questions about the airbox area.  First, is there normally any sort of gasket or seal that goes around the flapper (the actual metal piece that moves up and down) in the airbox?  On mine, there's enough space around the flapper where it sits in the plastic housing that it would let a lot of air through even when the flapper was closed.  I'll post a picture later in the day when I take the bike apart for some more tuning.
My second question is in regards to the vacuum diaphragm that sits in the little "cup" that attaches to the right side of the front carb.  The factory parts diagram lists it as "element assembly".  What is this and what purpose does it serve?  My bike doesn't have it installed and I just have the vacuum ports on the carb and intake plugged.  Will this cause any running problems?
Here's a picture of the diagram with the part in question circled.  Thanks.

[Jimustanguitar]

The part you've circled is a small air filter. There's a circuit on the carbs that requires atmospheric pressure, and that filter just keeps the crud out.

[TheRadBaron]

Oh, okay.  That makes sense that it's a filter since it's called "element assembly".  Looking at the diagram, I saw the line going to it and assumed it was a diaphragm of some sort.  I have that line plugged now, so I'll unplug it and see if that makes the bike run better.  Thanks.

[QBS]

The flapper on my '83 is designed to be held slightly open by a small rubber stopper.  The flapper must not be air tight.  This is to allow air in for idle state operation.