The pin is a tight fit in the frame and so a small press would be useful. Otherwise soak for a long time with release oil, lay the frame on it's side with suitable packing and knock it out with a drift and a big hammer. Some heat would also be helpful. It sounds a bit crude but it is not the best bit of engineering. The swinging arm pin and big end assembly are the worst of this machine
All the best with it, be patient!