I have an intermittant loud metallic type tapping noise from my B model banger mill, tap, tap, tap,......tap,.......tap. The noise only appears to happen at idle and is not always there, seems to be coming from the timing gear area of the motor. I've taken the timing cover off and run the banger for a short time, the noise is definately coming from the front of the mill, although the aluminium timing gears looks okay. Anyone got any ideas of what it could be? Gomez.