Overrevving (easy to do with the 2S cam) was the demise of the Combat. Treat them fairly and they won't blow.
I don't know what you mean about the gearbox needle bearing, I believe you mean the roller bearing conversion (although higher quality ball bearings work better) on the mainshaft? That was not Combat specific, the blame has traditionally be placed on Portuguese source ball bearings and affected only some bikes, more likely then 850s.