Bongster wrote:Hi there, can anyone help me with electrical quadarey on my moto vespa 150s

. Basicaly as I wasn't going to use the original engine, I bought a loom for a gl as that was the engine I was going to fit(it was knocking round my garage), but I managed to get a decent px 125 motor I now have major confusion as to what I can do other than change the loom. I'm not much of an electrician,but can do simple wiring but this just seems to complicated

Pretty simple really. Assuming your GL is a non-battery version. if it had a battery, you might need to get an AC horn as well as the brake switch wiring conversion.
PX engine has single blue output wire? so you will use a 3 plug AC regulator
Only modification you have to do is convert the rear brake wiring from a "breaks the circuit" constant ground, to a "complete the circuit" type.
The GL loom will have 2 blues at the engine, joined together. cut the join. one of these wires now runs to the brake switch, the other runs to the tail light. they might be light and dark blue so easy to tell the difference, if not, just use a circuit tester or experiment a bit with pulling the wires at the section of the loom where all the wires are exposed.
Once you know which wire runs to the tail light, pull that wire out of the bit of sleeving that runs to the engine, so it is not in any sleeving. Run this bit of wire up the sleeveing going to the brake light switch. That sleeving currently has a black and blue in it. You can pull the black out to make it easier to do so, if you need.
Buy a "DC", small type brake switch. there are 2 old vespa type switches, AC and DC. the big 1" square one is the AC one, the one that is 1" tall and 1/2" wide is the DC one. The DC one will complete a circuit when you press the brake pedal.
Now, feed the blue from the px stator into the ac reg, feed the Yellows/Green/Newly SINGLE blue from the AC regulator, connect up your brake switch with the 2 blues, and you are set. Convert bulbs to 12v
not too bad right?
-Gene