Not really a "break-in" period. Most builders recommend running the hell out of the thing right off the start rather than babying it. Everything is so close in tolerances these days the old days of "seating" the rings are gone, "ride it like you stole it" is the way to go.
Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power
I think the recommended break in helps extend the lives of the average busa rider rather than the life of the machine.