I have a Max .12 MF with ceramics, we run 16% for clubs and nationals here, the engine has done about 3.5 litres of fuel, never had to change the bearings, just the conrod and the wrist pin, i do however after every meet put about 2-4 drops on after-run oil in the engine and drop in the carb and turn the flywheel by hand a couple of times.

If you dont overheat the engine, all the internals, bearing included will last alot longer, 3.5lts on the same bearing and they are as good as new.