BSA GEREEDSCHAP

A word on extractors. Everybody can ruin an extractor by overtightening and stripping the threads.
Make sure the threads are all clean, screw the extractor in as deep as possible. Turn it carefully tight. Then give the bolt a sharp blow with a hammer and usually the hub pops off. If it does not want to come off, try to heaten the outside of the hub and keep the underlying shaft cool.
Good luck.