RE: Open or shielded bearings for a DA 85???
You definitely want to use sealed bearings (2RS) in your engine.
They have to hold crankcase pressure otherwise you will get a decrease in performance. For the front bearing, try to get an NTN with the orange seals for the front bearing. The orange seal is a full contact seal and withstands pressures better. The rear bearing has to be a factory bearing as it has a special radius on the inner race. Try and contact a DA dealer in Europe.
Cheers
Alan