I have an 06 F4i and my lid is the shoei Gt-air. I also have the zero gravity touring windshield and i too was getting a lot of wind noise. I didn't have it that bad with my old rf-1000 which was pretty beat up. I have a strong feeling that the taller wind shield produces more wind noise by pushing the air up higher then the stock. When i get my bike running again i will switch back to the double bubble and then the stock to see if there is any difference.

 

I have a double bubble and if I dip my head a little bit I get that booming and buffeting sound and if I go lower into a full tuck it goes completely silent. I agree with donny its the windscreen that is causing the issue and the helmet is a small part of the equation.

 

http://en.wikipedia.org/wiki/Drag_(physics)

Look in the top right and see photo. Look at your helmet shape. Look at the drag rating.

Looking up is more than likely decreasing the drag based on the shape the helmet takes in that position...

id say its the screen, think of where that air is being directed. Hold your hand out right at the apex.

maybe just maybe?

 

Dip my head as in lower my upper body towards the tank not tilt my head down.

Edit: I.E. no tuck, half tuck, and full tuck.

 

I my self use an icon airframe helmet,i had found it to be a bit loud,so i went ouy and bought another icon helmet,an airmada,it was a lot quieter,but the graphicson my airframe are alot more pleasing to the eye.so upin looking at it i thought of maybe swapping the padding from one helmet to the other so i can use the one i really like,thats when i seen the difference, my airframe helmrt had the left padding on the right and the right on the left,after i seen that and fixed it,i immediatly hopped on my bike and it was quite like my airmada.i bought both helmets new,somehiw from the manufactor or maybe retailer,the padding was reversed.......so my questioh is....hwve you checked the padding?i used mine for 2 monthw before i realized it was reversed