RE: How to disassemble O.S. 140 RX
I got it out now. A dentist mirror brought it to light. The problem was, that the piston pin was seized in the upper rod bearing and all what the rod did was to rotate the pin in the piston bore holes. After soaking with WD40 I could work the rod along the pin a bit to the side, enough to finally get the rod also off the crank pin.