I think I've made this comment a few times previously, but you know how us old folks are, we tend to repeat ourselves. If you want a quiet powertrain, DO NOT under any circumstances buy a 100 year old design otherwise known as H-D. If quiet is your thing, there are modern choices available that are much quieter (and more reliable as well). If you must have a Harley but can't stand the noise, a good set of earplugs will help. If you don't want any mechanical noise at all, I suggest one of the heavily insulated luxury automobiles with a high output stereo.
In all seriousness, a Harley is going to make all kinds of noises. The secret to not losing your mind obsessing over them is to determine which noises are "normal", and then only worry about the "abnormal" ones. Unfortunately, there is no simple way I'm aware of to gain instant knowledge of the difference between normal and abnormal, that comes with experience. We can try to help on this site, but trying to diagnose a noise is a little tough sitting at a keyboard. Find a mechanic you trust and develop a relationship, find some more experienced friends who can actually listen to your particular bike and compare with theirs, etc.
Jerry