A. Wiring Diagrams
Original wiring diagrams were scanned from original Owners Manuals, or Assembly and Preparation Manuals.
Original Wiring Diagrams for models without turn signals
No original available
1972-75 Vespa Ciao
4-wire magneto with
external ignition ground
Original wiring diagram
1976-80 Vespa Ciao
4-wire magneto with
external ignition ground
Original wiring diagram
1977-80 Vespa Bravo
4-wire magneto with
external ignition ground
Original wiring diagram
1978-80 Vespa Grande
4-wire magneto with
external ignition ground
Original wiring diagram
1979-83 Vespa Si
4-wire magneto with
external ignition ground
Original wiring diagram
1980-83 Vespa Grande
4-wire magneto with
external ignition ground
Original wiring diagram
1980-85 Vespa Ciao PX
4-wire magneto with
external ignition ground
All of these have an external ignition ground, which is the blue magneto wire. It must be connected to ground in order to have “spark”.
Original Wiring Diagrams for models with turn signals
No original available
72-75 Ciao with blinkers
4-wire magneto with
external ignition ground
No original available
76-77 Ciao with blinkers
4-wire magneto with
external ignition ground
No original available
1977 Bravo with blinkers
6-wire magneto with
external ignition ground
Original wiring diagram
78-80 Ciao with blinkers
6-wire magneto with
internal ignition ground
Original wiring diagram
78-80 Bravo w/ blinkers
6-wire magneto with
internal ignition ground
Original wiring diagram
78-80 Grande w/blinkers
6-wire magneto with
external ignition ground
Original Wiring Diagram
80-83 Grande w/blinkers
6-wire magneto with
internal ignition ground
Most of these have an external ignition ground, which is the blue magneto wire. It must be connected to ground in order to have “spark”.
Myrons Wiring Diagrams
Making these wiring diagrams was difficult and took over 150 hours of study. Some original diagrams were not available. To produce them, 1) all the Vespa USA-models and years had to be identified, 2) the parts catalogs and amendments were studied to make the table of electrical part numbers, 3) actual parts from Myrons inventory were photographed, or images from the internet were collected, to identify every electrical part, 4) some of the parts, especially switches, were tested to determine their internal wiring and function, 5) some actual wirings from stripped out mopeds were photographed and studied, matching each actual wire to the diagrams.
1972-75 Vespa Ciao
4-wire 2-coil magneto with external ignition ground
1972-75 Vespa Ciao with blinkers
4-wire 2-coil magneto with external ignition ground
1976-80 Vespa Ciao and Bravo
4-wire 2-coil magneto with external ignition ground
1976-77 Vespa Ciao with blinkers
4-wire 2-coil magneto with external ignition ground
1977 Vespa Bravo with blinkers
6-wire 3-coil magneto with external ignition ground
1978-80 Vespa Grande with blinkers
6-wire 3-coil magneto, external ignition ground
1978-83 Vespa Grande, Grande MX
4-wire 2-coil magneto, external ignition ground
1978-80 Vespa Ciao and Bravo with blinkers
6-wire 4-coil magneto, internal ignition ground
1980-83 Vespa Ciao PX
4-wire 2-coil magneto, external ignition ground
1980-83 Vespa Grande MX with blinkers
6-wire 4-coil magneto, internal ignition ground
B. Electrical Service
Magneto-Generator and Engine Wires
Top coil is ignition source coil. One end (red with eyelet) goes to the points. The other end goes to ground, either internally or externally.
Bottom coil is lights source coil. One end is grounded internally. The other end (with red plug) goes to the main lights.
Side coil is auxiliary lights, only on turn signal models. Both ends go to a rectifier for battery charging.
1976-80 Vespa Ciao
1978-80 Vespa Grande
1978-80 Vespa Grande
with turn signals
Vespa Ciao with blinkers, ignition wire behind points is corroded badly
Bad wires: 1970’s Vespa moped wires are often corroded badly. They all have faded brittle insulation that breaks in places, exposing the braided copper core. Here is a turn signal model Ciao with a vital wire shorting out secretly behind the points. All of the wires near the engine are cracked and corroded badly, in places. They break like glass when you try to bend them.
Vespa Ciao with blinkers, brittle and badly corroded condenser wires
Bad wires: The bad wire shown above is this condenser wire. This is a turn signal model Ciao, with the condenser mounted externally. Non-turn-signal models have internal mounted condensers. This poor wire is actively shedding green flakes of copper oxides. Also note that the blue wire (external ignition ground) is faded to dark grey. It is also cracked open and corroding. Both of these wires are needed to run.
Replacing engine wires: Many 1970’s Vespa mopeds need their engine wires replaced. Many have intermittent or no spark, or dim or flickering lights, because of bad wires. Some electronic or hardware stores sell braided copper wire by the foot, but some only have 50 ft rolls. The old connectors can be cleaned and re-soldered to the new wire. That requires good flux-core solder and some skill.