Laverda SF. Our cam followers are truly a weak point. I got onto Delvac 1200 40wt and it kept them healthy. I had a meeting with a Mobil oil technician at Mobil Oz headquarters (a big deal for me) and he recommended that over all their multi-grades. It was better in every way. This was at the time that they were about to release their bike specific synthetic which he recommended I go over to. And that is what I have used for the last 20 years, Mobil 1 4T Racing. Engine has been perfect, cam followers, slingers, clutch, the lot, both road and racing. Most people here hate synthetic though.
With my cam followers I destroyed 3 cam/follower sets in 18mths (started test riding Jap bikes as a result). In the end I found out that the centre studs were being held tight against the oil channel on top of the head, blocking it. In fact with a 1mm wire down there to keep the stud back I could not fit the top cover. The cover had been removed twice before that but was not deformed. I opened the stud holes a bit and have run with a piece of wire to keep the studs away ever since, even on customer bikes, to remove the risk. I also polish up the faces on the cam and followers any time I have them out.