Don't interfere with the oil seal, kurb. The crankcase cover will slide over the crankshaft - just make sure you've removed the key from the keyway first, or you'll destroy the seal. It's a Woodruff key (half-circle) so it may take a minute or so to get it out of the crankshaft.
However the crankcase cover is held in place by a pair of dowels as well as the 7 bolts. Just tap the other side of the cover lightly with a rubber hammer, one tap on each of two opposite points on the cover, then repeat. Be gentle, it will probably take half a dozen taps on each side. Once it's off the dowels, it just lifts off. But remember to remove the key!
