Digital gauge setup issues

[T1jeep]

I purchased a digital gauge and speed sensor from Amazon.
I wired up but my tach is reading double what my external tach reads. I asked the seller for a way to fix figuring it’s set up for wrong cylinder number.

I connected the blue/white wire for the tach. They are telling me I must have connected to magneto wire. I have no idea which is the magneto wire.

Can anyone help me identify the other colors in this connector?

Yellow
Green
White

Thanks