Can you be more specific? is it for all 2010 bikes.....is it because the neck on that year bike sucks?
Still haven't seen an actual copy of the letter or the service bulletin, but it appears that this "recall" (it still doesn't show up on the NHTSA website as a safety recall, even though it should) is in response to a problem that has been discussed on this site many times in the past. Some gas caps do not seal properly due to the fit between the cap and the threads in the filler pipe in the tank. Plenty of riders have reported that when they twist the cap until it is supposedly tight, fuel will leak out and run down the tank and on them as they ride down the road. While a cap that doesn't really seal is an emissions system defect, it is also a safety defect. Once again I don't understand how Harley gets away with this stuff.
The following was copied from a dealer website:
"The Motor Company is initiating a Voluntary Emissions Recall for certain 2008-2010 Softail® and certain 2008-2011 XL and Dyna® family motorcycles
. Upon exposure to certain types of fuel formulations and/or high ambient temperatures, the gas cap may develop a fitment issue of the gas cap on the tank. If this condition remains undetected, it may prevent a proper seal between the gas tank and fuel cap assembly, potentially allowing fuel-related emissions to vent through the cap. The remedy is have us perform a filler neck adjustment which will take less than 10 minutes."