If you look very carefully at the sides of the cylinder, there are two small slots (one on each end) that Honda put in these joints so you can insert a small screwdriver or other suitable prying tool between the pieces to help get them apart without gouging any delicate gasket mating surfaces.
As kghost said, make sure all the nut stud nuts and the small retaining bolts are removed before any kind of "encouragement" is used.
