Old sockets with the right OD, some big/thick washers and a bolt running through them, should be enough to remove any not-too-seized-in linkage bearings.
If the're stuck in aluminium linkages/rocker arms, then dropping it into an old saucepan of boiling water is often enough to free them up. The Al expands more than the steel bearing shell, and boiling water will never be over 100*C, so you don't have to worry about killing the aluminium.
