The Nuvi 765t does not have a headset-profile, only Audio device and Phone, I tried booth and they do find the helmet, but when trying to connect it seems to try with code 0000 and says "Could not connect", I suspect it is the wrong type of profile.

BMW R1200GSA -08, Schuberth R1 with Bluesonic, Garmin Zumo 660 not working with Bluesonic Sad