Here are the Cubase settings that work well when connecting directly from Motif to a PC.

In Cubase got to Options- MIDI setup -System and set the MIDI in to Yamaha USB 01- Mapped to USB 01. Set the MIDI Out to Yamaha USB01 and the mapped out to Yamaha USB 01. Enable Thru on Cubase.

If you are going to use the remote control features of Motif, Select Remote- Setup and select Generic Remote and set the Remote to Yamaha USB 0-3.

Go to the Remote box and click on edit, this will open a window where you can edit the remote control maps, on the right hand side select Import and import the XML file that is on the Motif CDROM in Cubase folder.