RE: Open or shielded bearings for a DA 85???
Alternator bearings, wheel bearings, and universal joint needle bearings do not have the luxury of fresh and replenished oil/lubricant supply. Your point is wll taken in the case of my new Enya SS.40BB 2 cycle with merely a shielded front main bearing. It's hard for me to understand why there isn't crankcase leakage. I'll know more when I diasseble it. It will not see a drop of fuel until the front main bearing is replaced with a sealed bearing. It will run with an air filter also.
Bill