This is a trick question. We need more data before we can answer it, as there are too many unknown variables.
A) Are you asking how much oil the engine burns, how much it drips, or the total of both?
B) Does this total include oil drained and replaced while tearing down the engine for rebuilds?
C) Should we prorate the downtime to adjust the annual mileage?
D) Is this Harley ridden by a white-collar poser who only takes it to rallies (usually on a trailer until he gets to the nearest hotel), or by the more stereotypical Harley bad boy who takes it to Johnny's Bar & Grill every Friday so he can park it out front while he shoots pool inside?
Gives us some more information and we'll get back with some answers.