Because the new main input shaft comes from the factory with a "facing" (I think that's the right term) on it, one must not exceed 40 mph during the first 2500 kilometers of usage.
This "facing" will be worn off by the action of the gears in the gearbox and float about in the 20W50 oil that is used within the gearbox.
Gearbox oil after almost 500 kilometers of usage.
As you can see, the oil is quite dirty and the metallic particles are visible floating within it. There should be, hopefully, much less when I do this oil change again in about 1000 kilometers.
Hopefully also, the oil will come out looking more golden brown than black as well!
Just takes a while, at 40 mph max speed, to rack up what will be a total of 2500 kilometers (1500 miles) of break in period riding.