I had the same noise in my engine and Pete ( Blueskies) Anderson listened to it at Bonneville, the engine was hot and the noise had quited down some. Have torn the engine down since arriving home because the rod will rock on the piston pin on #4 and#6 cylinders. At sometime I did something that caused the white metal on all six rod bearings to wear through to the copper and scored all six throws on the crankshaft but the mains are all ok. The piston pins are loose in the two rod bushings and will rock about .005 up and down in the bushing. The click is the play in the pin bushing when the piston reverses direction. Also had broken top ring on #5 and #6 pistons. Can almost guarentee that the click will grow louder as the rod bushing gains clearance. Before leaving on a 4600 mile round trip mine was not too loud but by the time I got home it was very loud when cold, pulling the plug wires made no difference. Click was not loud when the engine was warm.
