If you are talking about the fuel injector filters and the HP pump filters you are not going to find part numbers in the Yamaha parts catalog as Yamaha does not consider them to be a user serviceable part.
Rich Z should be able to provide a non-OEM part number for them.
For any that read this keep in mind that part numbers can vary amongst HPDI models. Always use the Yam parts catalog for your specific HPDI model.