Here we have two NOS 10mm OEM Stihl 044 crankcases with factory fitted case bearings, one is a very early version with the angled impulse fitting, the other case has the straight impulse fitting, apart from that they're the same case.....My question is in regard to the shielded bearings used in the later crankcase, surely a non shielded bearing would be more suitable in a two stroke engine?