I have a 99 yz 400 motor. Lats night it just locked up.. It has oil in it still and am not completely sure what the cause of failure is yet, but if it was the crank I am trying to figure out the best method to fix. I cannot seem to find an aftermarket 400 or 426 crank, but can for the 450.. I would like to go aftermarket because OEM is much more $$..Does anyone know if the 426 crank will just go into this motor?? what about a 450 crank? what are the differences if any?? I believe the 426 and the 450 crank differneces are the strokes, but not 100% sure.. anyone have any answers to this??