Papa,
Great side covers, you just cost me 212.00 ordered a pair after seeing you other thread.
The noise you hear is coming up from the bottom along with additional mechanical noise from the motor. The shield has created a sweet spot of calm air but is allowing it to come from underneath. I noticed more noise before i cut mine down. Some put lowers to combat that effect.
I cut down my shield so it gets all the wind off my chest ( hits right below the shoulders) but allows the wind to flow through my helmet therefore eliminates that noise your hearing. Below is my thread for your review.
Also, with it cut down it has not effect on handling, I find it to be even better than naked. Mine never comes off since i cut it down.
http://cb1100forum.com/forum/showthread.php?tid=1256