I dont know about you, but I consider one mandatory for the bike in Phoenix, AZ. This article tends to call it out as a placebo.


From the Fall 2007 Fuell Online Magazine:

Q. Abe, what can you tell us about the "right side air scoop" on the XBs? I've seen people fit larger ones (near mirror images of the left side) in an attempt to increase the cooling capacity. It seems the smaller one will allow for an increased air velocity and potentially more cooling. What's the deal?

A. The intent of the right side air scoop is to get better airflow over the fule rail when the fan is on (at low speed). Getting proper airflow to the fuel rail is important in order to prevent vapor-lock during extended idle or parade duty in hot ambient temperatures. It turns out that if this scoop has too big of an opening, the airflow is not directed to the fuel rail as effectively. In our testing, a right side air scoop created as a mirror image of the left hurt fuel rail temperatures at idle.

The left side air scoop was shaped to direct air to the rear cylinder and is very effective at doing that. During our high-speed, hot-ambient testing, the front and rear spark-plug base temperatures are virtually identical, whereas on the old tube-twin bikes there was a 100 Degree Fahrenheit difference (rear running hotter).

Supposedly it was in the "Ask Abe" section of Fuell®, Fall 2007. As explained by Abe Askenazi - Director of Analysis, Test, and Engineering Process at Buell.

(I'm just cutting and pasting it from an old thread on here).