http://cgi.ebay.co.uk/DUCATI-851-900-750-SS-SL-HI-LEVEL-RACE-SILENCERS_W0QQitemZ150022852713QQihZ005QQcategoryZ 10448QQssPageNameZWD1VQQrdZ1QQcmdZViewItem There probably 900SS /SL cans so you might have to have them cut and shut to match the angle of the seat on the 851
I,m running cored superlight cans on my 851/888 with no problems ,as mentioned I just had to have them cut and welded so that they did'nt look odd when fitted