Well, the RB is probably into it's 4th litre, I replaced the rod after between 1-2 litres. I doubt its an air leak, even still I sealed up the carb. If it is the bearings, how would I know? Maybe they do need replacing - what should I get? A normal front bearing (small one) and go ceramic for the inside one?
With the Picco's i did notice they broke in very quickly, felt no real difference after the 3rd tank like you said. Not sure how I did it, but I think I went like this:
T1: Heat it as much as I could, maybe around 150. Start it, riiiich bottom end, raised the idle speed via the screw.
Cool down at BDC for 10-15 min.
T2: Same as T1 but I let it idle at normal speed with stock "rich" settings, giving it blips every know and then.
Cool down at BDC for 10 min or so.
riving time - go around 1/4-1/2 throttle up and around my street for 2-3 seconds at a time.
Cool down for 10 min @ BDC
T4: Same thing, more at 1/2 throttle. Finished for the day.
Rest of the tanks were done on my track on fairly rich settings, all using an OS P3.
On one occasion when I was in a tournament, the last 2 races I noticed it lost all power like it was on the verge of being too lean but not being hot. After I finished and took it home, it seemed to lose a lot of air through the front bearing, more than I thought it should, left it like that ever since.