Modern Vespa

I have a 2008 Piaggio Fly 50 with less than 500 miles.

A few months ago it died while driving. I tried to restart, but there was absolutely nothing. The starter made absolutely no noise at all. The horn and turn signal functioned as normal. I tried the kick starter and there was absolutely nothing.

Today I finally had some time that I could devote to going over some things.
1. Not knowing if this particular year, make, and model has an oil sensor or not, but knowing that it has been a long time since the oil was changed, I drained the oil and cleaned the screen. I could not find an oil filter so I refilled as is. Again, just in case it has an oil sensor; once I had added oil to the proper level, I used the kick starter to at least rotate the engine a few turns, and rechecked the oil level. It is filled to the mark.
2. Next I removed enough of the plastic cover / trim pieces on the Left side to access the fusible link (large fuse on the outside of the frame assembly). Then using a Test Light I checked for voltage on both sides of the fuse and there is voltage to and from the fusible link.

When it died it was as if someone had turned the key off. To my way of thinking; those two, the oil level sensor (if in fact it even has one) and the fusible link are the simplest ones to check which could have cut the voltage going to the coil and could prevent the starter from receiving any voltage.

About a year earlier I replaced the ignition coil with an aftermarket unit that is supposed to be "hotter" than the OEM along with a new spark plug. The coil noticeably improved the performance.

I have also replaced the carburetor. Even though the carburetor has absolutely nothing to do with the electrical issue I simply wanted to document that.

I am not a mechanic by any stretch of the imagination. But if I have the ability to preform the repairs that I have listed then I am certainly not totally ignorant.

I understand that I am definitely dealing with an electrical issue, I just do know what else to do except to totally remove all of the plastic pieces, and using the Test Light to check voltage on everything from the battery to the ignition switch and on to the starter as well as the coil.

If you have any suggestions I will be in the garage checking voltage so feel free to speak your mind.

I pulled the front cover off to access the wires at the Ignition Switch.
Tested:
1. Key Off
2. Key On
3. Key On, Brake Applied
4. Key On, Brake Applied, Starter Button Depressed

From top to bottom;
See attached picture:
Green; small gauge; No voltage; 1, 2, 3, or 4
Black; small gauge; No voltage; 1, 2, 3, or 4
Red; large gauge; Voltage; 1, 2, 3, and 4
White; large garage; Voltage; 2, 3, and 4

So, in other words;
The large Red wire always had voltage no matter what.
The large White wire only had voltage when the Ignition Switch was turned On.

The other two wires; small Green and small Black wires never had any voltage. Irregardless of the Ignition Switch Off or On. Irregardless of a Brake lever applied or not. Irregardless of the Starter Button depressed or not.

I know that I am piercing the wire insulation because I can see the copper wire. I know that the Test Light is grounded because when I do not detect voltage I retest on the larger Red wire.

Because I do not have a wiring diagram for the 2008 Piaggio Fly 50 I do not know what the Green or Black wire go to or come from.

Could the issue be with the Ignition Switch?

Going by circuit diagrams of other Piaggio 50ccs, I would expect the black to be chassis ground (0V) and the green to be connected to the stator and to the CDI. When the switch is OFF, I'd expect the green and black switch connections to be shorted, when ON, to be open circuit. Test the switch with the wires disconnected.

You are correct.
Using a simple Ohms meter;
Key ON
Green and Black have 200 Ohms (NO connection to each other)
Green and bare metal have 200 Ohms (NO connection to each other)
Black and bare metal have 5 Ohms (are fully connected)

Key OFF
Green and Black have 5 Ohms (are fully connected)
Green and bare metal have 5 Ohms (are fully connected)
Black and bare metal have 5 Ohms (are fully connected)

Those readings sound spot-on. Those wires when shorted stop the engine running, as they will kill the stator pulses to the CDI.

JimC,
First and foremost I am grateful that you instructed me on testing the Ignition Switch, which if I understand correctly, is functioning properly?

If so, where else should I look?

I wonder if the Voltage Regulator might be the culprit and how I could test it for proper operation?

CALL OFF THE DOGS !
RELEASE THE PIGEONS !

I finally remembered that while dealing with carburetor issues I had watched a few videos by Robot of Scooters West so I did a web search and found the video below.

Five minutes into the video and Robot said to check the Engine Kill Switch. When I did everything worked perfectly.

Backstory: At Christmas I was letting my 11-year-old grandson drive it by sitting behind him with my hands on the very end of the handle bar. As he progressed I moved my hands to the instrument panel. We then went to the mailbox with him driving and my hands to the instrument panel. As we left the mailbox he must have shifted his hand and or thumb because it smothered down and died just as we topped a small hill.

After several failed attempts to start the only thing that functioned was the horn and turn signals so we pushed it back home where it has been sitting and me moaning because I did not have the time and expertise to deal with it.

Now I just need to clean the carburetor again and I will be off to the mailbox and corner store at the maximum speed of 25 MPH, 40 MPH when going downhill with a strong wind on my back.

I apologize for calling for help without searching for a video, but I am also so thankful and happy it runs now.

THANKS !

How to Troubleshoot a Modern Vespa That Will Not Start/Crank Over
November 22, 2021
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Vespa Motorsport
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Well found.