I run the 665 and Scala G4.Well first off it is the Zumo 660/665 that is going to give you a problem. I had to go to http://www.zumoforums.com/ to search for alot of my problems with the bluetooth audio. To this day with updates and following the suggestions I still have problems with the bluetooth end of it. For phone calls, if I'm stopped they can hear me but driving they seem to have a problem. I think it is more wind noise (Icon Alliance), because I can hear them. BTW.....if I remember correctly didn't you sell a 665 that you were givin? Did your pal pay you to take it? I know... But I think between this forum and the Zumo forum you should be able to get it work.
The Zumo has a built in mic?
Zg, I have a 660 smh10 and droid razr paired without an issue. I would recommend you upgrade the firmware to the latest version in the 660 and scala first off. I believe the major issue is usually getting the scala and iPhone on the right bluetooth channel on the 660. One I believe is full a2dp and the other is not so sometimes the phone can grab both channels and not allow the scala a channel to work on so the person might have heard you through your iPhone rather than the mic on the zumo.One last thing I noticed with my 660 is its very tempermental when on battery power verse when the bike is running and from time to time will drop the Bluetooth while riding and I need to reboot. I tend to ride all the time with my droid paired directly to the sena playing pandora, no caller I'd but I can deal with it over the cumbersome feelng of everything going through the gps.