Im pretty sure if you ask HD they will tell you its "a Harley thing"

I wash mine less now ,Id rather the dirt than rust ....the dirt hurts but the rust kills me

Also check your welds ,I had to touch up one on my swing arm

Try and keep your tank full as much as you can, also don't use ethanol blended fuels as it absorbs moisture.

mine went the same too looks like shit . i was told the hd thing as well as the chrome too , keep an eye on pipes etc too