Would this ecu fall in recall period?
I tried holding in the reverse override switch test, to test that circuit and see if the problem would go away. Nothing happened.Brown is ground - black is kill - connect the black wire of the ECU to ground and it kills the spark - disconnect the black wire of the ECU from ground and if it sparks, the ECU is good and you just have to find where the black wire is connected to ground - if disconnecting the black wire of the ECU does not restore spark, then you have to fully troubleshoot the ignition system.
Now, you have spark because it will idle, right? And when you open the throttle it dies, right? If it's not the throttle switch, and it is not the key switch, and it's not the handlebar switch, that leaves the reverse limiter which is in the speedo, but the speedo is tied to the stator - if it's the reverse limiter causing the problem, holding the reverse override button in while opening the throttle should allow it to accelerate and you only need to determine why the reverse limiter (speedo) is cutting spark.
So if you eliminate all ways to kill the engine and it still dies upon opening the throttle, then the problem is either fuel or a component of the ignition system which is ECU, pulse coil, or primary coil.
Process of elimination