I just got done doing my RM. I'm assuming your KX is going to be similar. There are conventional paper gaskets between case halves and the r/s crankcase cover. Yes, the kick starter assy., clutch basket, shift shaft, shifter drum pawl assy., primary drive gear, and any water pump and power valve stuff will have to come off. Once the case bolts are out the r/s case is pulled off using a case splitter, modified puller, or a non maring hammer as a last resort. The main bearing should stay in the case. Then the crank is pushed out of the left side case and again, the bearing should stay in the case. Because it's an interference fit, you should heat the cases when pulling the old bearings out to prevent damage to the case bore. Likewise, the cases should be heated and the new bearings frozen when installing them.