Elect. problems fitting a primavera motor to a 50N vesp

Hi all you scootergurus…!

I have had a ´67 50N vespa standing in my garage for years

Now i want to use it, and therefore I have bought a primaveramotor on ebay in very nice condition

It is now fitted, but i cannot get any sparks from the plug (have checked by holding the plug to the cylinderhead…)

when I remove the ignition coil, plug and cord, and build a „teststand“ on my workbench, I can get a decent spark by touching the feedpole on the coil with my 6V battery charger…-so I guess that all those parts are ok…

The statorplate and the points seems very fine, almost like new.

One of my concerns are the fact that there are coming 5 wires from the primavera stator plate, and not only 3 as on the old 50cc motor:
(no brakelight and flashers on the scooter)

red = ignition kill switch
green = 6V lightening
Black = ground
(thats how I figure it)

From the primavera stator plate:
Red = from condensor and points = to kill switch
Black = ground
Blue = 6V (as I see it for brakelight)
Green = 6V lightening…???
Yellow = 6V (as i see it for flashers)

If I connect red-red, black-black and green-green, i can connect at testlight between the red feedwire to the ignition coil and ground, and get it to light up, but if i connect a continuity tester the same way and turn the flywheel by hand ther is constant contnuity all way round

if i disconnect the green-green wires, I can get hear the points open/close with the continuitytester, and cannot get the testlight to light up

(sorry I am used to work on cars, but the way i have figured it out the coil should get 6V-ground-6V-ground-6V-ground-… and so on from the stator plate)

should I connect all the 6V wires: the blue, yellow and green (parallel) to the green wire from the wireingloom on the scooter to get more 6V amps ?

I try to use this wireing diagram for reference:

any input would be greatly appreciated

messenger: [email protected]

Check me working in my garage on my webcam:

I would start by disconnecting the stator wiring from the main loom.

With the red wire from the stator connected to the coil you should get a spark at the plug, the kill switch works by shorting the coil feed to earth.

If there is still no spark at the plug then remove the red wire from the coil and hold it near to the engine casing while you kick it over, you should get a small spark/crackling noise. This would point to a faulty coil or a bad earth.

If there is still no sign of life then it could be dirty/pitted points, faulty condenser or a dry solder joint/bad earth on the stator plate.

I will e-mail you a wiring diagram for the Primavera, hope this helps.


Thanks for the diagram Stringy…!

-I have the motor running now, but still need to figure out what to do with the yellow wire…(I will try to ground it too…)

All this AC confuses me, -and i still havent found out how exactly the little switchbox on the handlebar works internally - DC current is much more logik to me

Now I found out that if I bridge the black and blue wire coming from the statorplate, and disconnect the wires from the wireingloom in the scooter, I can get ignition…

(apparently the brakelightswitch bridge these two cables when not in use)