FZ6 S2 Engine Noise

[Fazermike]

Another way that may help determine if it's a rod bearing..

Pull the spark plugs and one of the side covers that cover the crankshaft.

Put a screw driver down (one at a time) the hole till you touch the piston.
Gently rock the crank back and forth slowly and see if one piston doesn't move SLIGHTLY like the others..

Or, pull a spark plug WIRE, one at a time with the bike running and see if the knocking gets lower/goes away... With no combustion going on, it WON'T knock nearly as hard....

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I might give that a try ...thanks

 

[Gary in NJ]

Bearings don't shed material like that. A worn bearing is one that has worn through it's protective surface, a surface that is measured in thousandths. I've attached a photo that I took from an engine that I recently rebuilt. The bearing on the lower portion of the photo is serviceable (but is showing signs of failure) and the one circled is worn. You can see that the protective bearing surface has worn through to the substrate below.