I get the impression that you have not fully dismantled the engine components from under the side covers ?
To get the cases split you have to pretty much remove all the components that are under the clutch and generator covers - clutch , centrifugal filter , primary gear , generator , gearchange shaft , sprocket etc. Apologies if I misunderstood but as Crazy suggests maybe some pics might help ?
The cases might need some persuasion to come apart as you are separating doweled joints and the main bearings from their housings but shouldn't need "force" - be a bit cautious .
To get the cases split you have to pretty much remove all the components that are under the clutch and generator covers - clutch , centrifugal filter , primary gear , generator , gearchange shaft , sprocket etc. Apologies if I misunderstood but as Crazy suggests maybe some pics might help ?
The cases might need some persuasion to come apart as you are separating doweled joints and the main bearings from their housings but shouldn't need "force" - be a bit cautious .