You usually have to heat the crankcase up and then use a rod down through the hole to tap the bearing out of the hot crankcase. I like to use a hot air gun inside and a propane torch outside. The idea is to heat up the crankcase and not heat up the bearings as much, so the bearings stay cooler. Sometimes the bearings pop right out with a sharp rap on the table, sometimes they don't. I use a 1/4 inch brass rod that now has a bit of a lip on the end, to tap out the bearings from the inside. I use the rod though the back for the front bearing, and reverse the rod to the front to tap the rear bearing out. Sometimes the old oil, varnish, castor, corrosion, etc, tends to build up around the bearing locking it in place a little on you. You want to heat up the crankcase, but only hot enough so you have to use leather gloves to hold it, and not more than about 240 degrees F or so. Somehwere above 250 degrees F and the crankcase will expand, but not shrink back when it is cool.