I have changed the upper bearing. I scrapped it and managed to get all the needles out with the help of a magnet. (Put some paper or a cloth in the hole before you start). I didn't change the lower one though. They are both the same size. I think you have to dismount the engine to do it. You can not extract it unless there is a special tool which does the job - as you mentioned. Maybe someone else knows?
/John