As of this date being my 4th 14, I had the opportunity to experiment with break-in theory 4 times. Both early gen bikes of the 4 had a hard break-in. The later models were book broken-in. Each time the clock came around to 3k miles I'd changed the oil. The hard break-in bikes needed oil to be topped off before the 3k intervals; whereas the book break-in bikes never lost their level in the sight window.
As far as power concerns, the latest [book]-bike feels stronger than all the others. As per book, for the first 600 miles, the engine never reached 4,000 rpm during the first round, nor did the engine ever rev past 6,000 rpm until 1,000 miles was reached during the second part of the book's break-in period.
The last 2 bikes were book-broke, showed no oil loss at the window; said go fuck yourself and your WOT job routine before 20 miles is shown on the clock... the junk science says so.
If I recall, both book-bikes clocked out on the OEM oil it came with. At this 600 mile change, I mixed [and have been mixing] 2qts of 50w racing with the remaining quarts of 10w40,10w30 leftover oils from the car's oil changes, and whatever syn is hanging around.
The levels in the window never showed signs of incontinence with this recipee of liquid refinements of said light sweet crude(s).
Signed,
NOLTT (new old leftover tipping trick)
Tormenting the motorcycling community one post at a time