Your problem sounds a lot like the one I had: https://www.ducatiforum.co.uk/threads/front-brake-vibrating-fix.81351/ To find out, you could measure with a dial indicator if the disk is out of plane. If it is, I'm afraid there is no remedy except replacing the disk (it is probably just one of the two) or grinding it: -it should cost 60 to 100 EUR: http://bremsscheiben-schleifen.de/leist.htm https://www.roadrunner-bikeshop.de/de/beitraege-bremsscheiben-3696 https://www.scheuerlein-motorentech...scheibe-planparallelschleifen-gekroepfte-form I bought mine for a very low price here: https://carpimoto.it/it-CH/