magnet that contacts the flywheel, wiring question, HELP

[Black R/T]

the magnetic pickup that the flywheel passes by (part of the timing for the spark i guess) broke on my brothers bike. we got a pickup that will work but we dont know which wire goes where... on the harness there is a blue wire with a yellow stripe and a green wire with a white stripe. which is positive and which is negative?

[wilkin250r]

There really isn't an easy way to figure that one out.

Both wires get fed into the CDI, neither is attached to chassis ground. There is definitely a "direction" to the coil, but I don't know how to figure it out. Reversing the coil wouldn't damage the coil, but it would send a reverse pulse to the CDI. I have no idea what that would do. It might just throw the timing off a couple degrees, but it also might blow the CDI.

I'm an engineer, I'm not just blowing smoke.