Its the oil ,,, not saying its bad oil ,but it thins out when hot and then you get the tapping like you are talking about and after a good cool down it wount have the same noice untill it gets hot again,, I have had the same tapping for 40,000 miles in my 08 ultra,, and to tell the truth it was driving me nuts ,, untill i installed a Baisley oil 15% spring,,,, now my motor is tap free,, a few buddys here where i live have allwas said its just the way harley is , and yep you guessed it.they said to turn up the radio or get louder pipes , but i allso know thats not right ,,, i looked in too the oil system on the motor and learned a lot about it ,, found the falts it had and thats why i did the spring , now 3 of my buddys allso put in the spring and they too are loving the motor the way it is running ,,,
So look at the spring and call and talk to the guys there at Baisley , they are good bunch of guys and they will tell you what is going on and how the spring will fix that tapping noice you are hearing
Jmcd