Pulled out the engine to paint the frame and to see where the engine noise is coming from. The top end rockers, valves and cam with routine wear. Cam chain tight. Decided to look into the cylinder and noticed that there are some vertical scratches only on the intake side of the cylinder wall! It is deep enough that i can feel it with my finger. Is it time for a bore? How can i tell that it has been rebore. Will the piston have any marks indicating that it is oversized? What could have caused the scoring in the cylinder wall? Connecting rod issues? improper Lubrication? Lastly, could this be the cause of the engine noises? Thanks in advance!