Well , on the bearing failure issue , This is what I have noticed on EVERY SINGLE ONE ,(premature failure), First thing was that there was gauling in the engine case under the top left portion of the case (looking at the bearing from the rear it would be between 10 and 11 on a clock). Now this was only on the ones that failed early. I saw it on 2 Novarossi's and on EVERY SINGLE O.S. ! And I changed a bunch of OS bearings before they were ever even started and it was the same there too. So I think the trouble is NOT REPEAT NOT the bearing it self but in the installation !! These bearing are being pressed in cold ! This is the only way you get this gauling effect, plus the build-up of excess material under one side of the bearing is stressful on it ,thus failure prematurely.
Any of you guys doing your own bearings LOOK FOR THIS !! If you see it then you need to clean that material out of there so the bearing can sit flat on the seat it was designed to fit on.Be careful not to gouge anything up doing it though, I use a very sharp exacto knife and then polish it up if needed.
Always use the crankshaft to aid in the installation too. After the bearings are installed lube the heck out of it and let it cool before removing the crank.
Make sure the crank spins super free too before letting it set to cool off.
Once in a while you need to give it a light tap to seat the rear bearing completely.