upper crank bearing

[jg112208]

I have a 2001 LZ 200 TXRA. My mechanic is telling me that water in the fuel may have caused a knocking that he thinks could be the upper crank bearing. that just doesn't make sense to me. any one have any thoughts? There was water in the fuel tank. how could that damage the bearing?

 

[99yam40]

Just a guess , but if you run water threw a motor it will be getting on bearings as it goes through the crankcase going to the cylinders