2004 VX225TLRC bearing failure

[Jaharr206]

Motor started knocking. Broke the powerhead down and found both center main bearings were damaged along with the crankshaft. All rod and wrist pin bearings look fine. Looking at the setup I'm not seeing how the center mains get lubrication. Anyway if anybody can tell me how they get lubrication or what may have caused this it would be appreciated. Don't want to put it back together just to happen again. Thanks.

[99yam40]

pics may help someone to see color of bearings and crank so they can give input as to what caused the failures.
Did you see any sign of rust in the crankcase or crankshaft?.