Yobit has problems, Please don't use yobit , And the 1 kB3 = 1000 B3, kB3 is a trading asset, and B3 is coin, exchangers which are at old wallet have B3 unit as default, and which are at new wallet have kB3 as default unit.
Max transaction size was 2 M in kB3, but now it is 622M, it was announced much earlier.