Truth is, most dealers don't stock any significant amount of parts at all, outside of oil/air filters, spark plugs, tire valves, and other cheap consumable items.
A whole world opened up to me when I started working on my motorcycle myself. I can get parts delivered straight to my door, there's no dealer markup on any parts I buy, and I save myself labor rates of $80-120/hour by doing my own work. And I do it on MY schedule, not theirs.