There are 3 wires to the Koso to give it a signal so it can tell you how fast you are going (based on a signal from the bike's sensor).
The negative wire (green) from speed sensor on the Koso needs to be connected to a ground. So all you have to do is connect the green and black wires from the Koso to the black/yellow on the bike.
Originally Posted by sportyaccordy
Howd you figure out what connector it was?
I think I spent ages looking through various suppliers until I found one that was almost exactly the same. When I knew the manufacturer it was easy enough to look them up and then find somewhere that sold them to consumers (most places wanted orders of 1000+ !)