My '08 Road Glide had the front fork air baffle, so when I noticed that my '11 Ultra Classic did not have one, I bought one since it made a noticeable improvement in wind management on the Road Glide.
I didn't really notice any difference with it on the Ultra Classic, but I left it on.
So yesterday I'm traveling between the Blue Ridge Parkway and the Cherohala Skyway and I start to hear a pinging from the engine when under load at mid rpm's. I back off the throttle and/or shift to control it, but I'm not too happy. Of course, it's 90 degrees outside and I had just finished a "spirited" hundred miles on the BRP, so I'm sure that the engine was quite hot.
So anyway, I stop at a pullout on the Skyway and up comes a fellow on a brand new Electra Glide Classic, and I ask him if how his engine is running on this hot day. No pinging, he says, and points to my air baffle. "That's your problem - the top end of the engine isn't getting enough air to stay cool."
So I whip out my tool kit and remove the baffle. Let the engine cool down a bit while I ate my lunch and admired the view. After getting on the bike and finishing my ride - in fact, all the way home back to Atlanta (with temps bumping 100* at street level) - no pinging at all.
I know these bikes run lean and would be prone to the pinging on such a tough day, but I was surprised at the difference removal of the air baffle seemed to make.