I have had a mysterious light tapping on the right hand side of my Black Guzzi for a few months now.
I took it for a MOT back in September and it was fine and a couple of days later I went out on it and it started. It really was hardly noticeable under all the other Guzzi noises but a month or so later it became more noticeable and at speed too but didn't sound serious. I was expecting a badly worn cam follower or rocker spindle or.....?
Anyway.I took the right hand head,barrel etc off and could not find anything as yet, except a couple of tiny pits on the high point of the cam lobe on the inlet and a little pitting on the corresponding follower.
What I did notice was that the con rod was staying put when normally it should move very freely. Moved it about whilst turning the crank to find tight and loose spots.
I took the sump off today and removed the con rod bolts to find what you see in the pics below.
My friend Martin reckons it looks more like corrosion than wear and I must admit the crank does look / feel to be ok
I have certainly opened a can of worms but obviously it's better to find it now before things got any worse.
I still don't know what is likely to be the cause of the tapping noise