Hi,
I own a 1977 Honda cb550f. It has developed a tap tap tapping noise that sounds like it's coming from number 1 cylinder exhaust tappet. I have removed the cover and there is no obvious damage the cover. The strange thing is tho that if I disconnect number 1 spark plug the noise stops. As soon as I reconnect the plug cover, the noise returns. Any ideas would be greatly appreciated. Thanks......Pete