Just to be sure...
After the Sena is turned on, and the bike is on, press and hold the jog wheel until the light next to it rapidly flashes red. Then press and hold the
Mode and
UP volume on the bike until you see the indication on the dash display that it's paired and hear the tone in the helmet. Makes a big difference holding UP or DOWN volume when pairing. Up is for helmet headset and DOWN is for BT music device like iPod or smartphone.
I did this while holding the helmet rather than wearing it but so I could also still hear the headset speakers.
You don't need the engine running, putting it on Acc should be fine.
After it is paired you use the Mode button to toggle through the options shown in the upper right of the LED dash display for speaker or BT output together with USB or BT input. There is a small arrow symbol showing direction (from input type to output type). in the very right upper corner of the LED display, with audio on, will show an arrowhead pointing to the right, then the input type (BT or USB), then the output type (speakers or headset). The symbols to the left of the arrowhead (more in the top center) are what the bike recognizes is connected for USB or BT devices (input then output). So you can see what the bike sees is there in the top center, but you see where the bike is getting input and sending output in the top right.
Make sure you have something playing through the bike BT or USB input to make it easier to hear when it's set right. Verify by setting your music to play through the bike speakers and then use the mode button to change it to the Sena headset.
I hope this makes a little bit of sense and doesn't jumble things up for you. :350x700px-LL-66dd6d