I bought my 250 new gen brand spanking new and put the very first mile on the bike. It has made that whine since mile 1, and with 5k+ street/track/race miles on it, it makes the very same whine to this very day. No harm in ensuring proper operation though.
Stopped worrying about it long ago...
Earplug tip is valid: they dull the less important stuff so you can hear vital things.
EDIT: Now that I think about it more, seems the whine is less pronounced on higher mileage bikes.