[mike in idaho]

Have you adjusted the balance chain lately?

 

[mike in idaho]

Did it land on the exhaust pipe? Sounds kinda like a leaky exhaust pipe joint.

 

[mike in idaho]

While it's running short out one plug at a time and see if the sound changes(rod knock). Running in gear, with the clutch pulled in, will stop all the transmission parts from turning to rule out noise from there.

 

[mike in idaho]

Drag a magnet through that oil, see what it picks up. Bearing shell material is non ferrous(non magnetic) steel particles will adhere to the magnet.