I found the following on another forum. Used it to attach a 1/8" plug and earbuds in place of the speakers.
I think it is looking at the pinout on the bike. The plug on the cord would be reversed. You might want to doublecheck with a voltmeter.
Ultra Headset DIN Plug Pinout:
Looking at the 7-pin connector with the index groove in the connector at the twelve o'clock position, the bottom pin is #2. So clockwise from the index groove the pins are #6, #1, #4, #2, #5, #3, #7.
6 is the shield/ground (one o'clock position)
1 is the microphone input (three o'clock position) (-)
4 is the microphone ground (five o'clock position) (+)
2 is the speaker ground (six o'clock position) (-)
5 is the left speaker positive (seven o'clock position) (+)
3 is the right speaker positive (nine o'clock position) (+)
7 is the handheld PTT (eleven o'clock position)