Originally Posted by boatpuller
It's not the wind shield, it's the air coming up around the tank that gets caught under/in your helmet. Try putting your feet up on the bars and "hug" the tank with your legs. You'll find very calm air behind the RK windshield.
It's also the wind coming over the shield, as evidenced by the big difference in buffeting when the Wind Splitter vent is open directing air upward to counter the wind coming over the shield, and when it's closed.
Btw, I also found that the National Cycle hand guards also greatly improve wind protection by blocking a lot of the air that gets around the sides of the windshield