You need to know what exact model you have and look up the wiring diagram here
https://vintagemopeds.files.wordpress.com/2013/01/puchserviceweb1.pdf
Sometimes people mistake a blue black for a black
On my 1980 Maxiluxe The 2 black wires just reconnects on the other side of the bus and the blue ignition coil wire could be on either side
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