The top end noise you are hearing is more than likely what is called the "flapper valve" on the air box.. Sometimes they can be very noisey /sounds like a small animal under the gas tank trying to get out ..lol. This does not happen constant ,so your local honda mechanic will be un able to locate noise..clean the linkage on the flapper valve and oil it so it moves easily .. It cured my rattles and growls on my 5th gen.