Hi Jonny....noticed the pic of the bearing. I've seen this kind of thing on cam-chain and cam-belt type engines (in cars, at least). Usually fired up and revved/run hard before the oil pressure comes up. Always on the "front" end of the crank. If you bought a used engine/bike...well, now you probably know a little bit of its history. Part of that condition can be promoted by oil choice (too thick....some cool guy using RACING stuff for the street) which makes the film build late on a cold engine that is treated badly.
This may mean the crank and block will prove to be straight, when you check it out. Regarding "front main bearing" clearance; in Toyota-world, we often "select fit" one step tight on that bearing, to prevent crank thump when the modern "fuel efficiency" oil is fully heated, and the engine idles for long periods. By the way, I don't mean "one step, as in .010"....it's more like .0005" difference. In those cases, all bearings are replaced, but the front is selected "one step tighter". We've been doing this since the early '90s and I've seen Lexus V6 run 300,000 miles with this fitting.
I don't know if the Hayabusa experiences that condition; I usually see it on "sequential throw" cranks, as opposed to "opposed throw" cranks (boy, that's a butchered up sentence!) Anyway...my bet's on a mean former owner.
In the decades I was a line tech, I had a good friend worked next to me for many years. He always said, "These cars want to run, people just won't let 'em!"
Regards, JimL