Most engines have the cylinder and crankcase in one casting: having them separate makes the engine too heavy, and less rigid. In general, you remove the cylinder head, then dismantle the connecting rod by undoing the "big end bolts" - the bolts that hold the two piece connecting rod together around the crankpin. After removing the lower piece of the connecting rod ("bearing cap") you push the rest of the connecting rod, still connected to the piston, up the bore and out.
