Modern Vespa

Hi All, i have a few questions and electrical issues that I cant quite understand..

While riding my PX for a period at high revs, I noticed after the ride that some of the electrics was no longer working.
No headlight, park-light, blinkers, fuel guage or speedo light.

I noticed that the fuse was not blown.
I checked my park-light and headlight bulbs and they were blown?

I have ordered a new voltage regulator as they appear to be quite a common part that often give-up and need replacing.

Hopefully replacing the voltage regulator and the affected bulbs will solve this.

When the reglulator dies and generates to much voltage can this also kill the speedo (fuel-guage) just as it blows the bulbs?
Why they dont have an inline fuse that prevents the over-voltage from the regulator which in the end will kill components, like bulbs, etc?

Or maybe I have misunderstood something...which is probably the case

Cheers Robbie

Exactly which scooter are you talking about? Some years run headlight and some other lights using a dedicated AC coil on stator and no regulator.

Thanks Christopher, good point..
Its a 97 PX 125 (VNX2T) with Electric Start...
With such a regulator.... https://www.sip-scootershop.com/en/product/voltage-regulator-piaggio_23082400

Any feedback that may help would be really appreciated.

I looked at wiring diagram, I can't really help, not familiar with that setup, and I have nothing to measure for a reference. There's a wiring diagram here if it helps.

https://www.scooterhelp.com/electrics/pages/VNX2T.px125e.html

Thanks Chris…
Will help me with tracing back any issues in the wiring..

No idea why there's no fuse to prevent AC surges from blowing bulbs. Not really a fire hazard if you lose a bulb compared to a battery overcharging. Guess the regulators haven't had enough complaints if the AC side blows?

Regulator failures are pretty rare. Hopefully it'll be another 25 years or so before you need another!

First off, make sure what kind of stator you have. If it's a 5 wires stator (blue & black for AC output), correct diagram is this...

https://www.scooterhelp.com/electrics/wiring/VSX1T.4KZS.5KZG.mit.Standlicht.pdf

If it's a 7 wires stator, correct diagram is the one Christopher posted above and then you have the wrong regulator for it...

This is the one for 7 wires stator...

https://www.sip-scootershop.com/en/product/voltage-regulator-piaggio_29401650

And finally, try to get a Ducati regulator. Piaggio (AEL, Kokusan), Swiss and whatever comes from India / China, is crap...

Cheers MJ
Good points you made.

Thanks Safis
Mine is a 5 pin G/G/B/C/Earth.

The new regulator I have was in a Piaggio box but as you mentioned is a AEL I believe…
Looking on Scooter Center website they say "they cant guarantee the brand of regulator they deliver as Piaggio has different suppliers in both Europe and Asia"
Unfortunately I cant return the one I ordered which is one of those knock-offs ☹️.
I will try and locate an original Ducati one as a spare.

Whats your experience Safis? Have you replaced quite a few regulators in the past?
Ive read in different places that they are a common part that fail?

Have you gone through the bike with a multimeter?

Higher vibration can do crazy things with connections.

Can you email a local parts supplier with a picture and see if they'll ship you the right regulator/rectifier? Probably faster that way than emailing SIP/SC. Same language too!

While I've see regulators fail, I wouldn't say they're a common occurrence. I've had reputable branded ones pop twice in a year and one that went after 30 years. Hard to tell with sealed electronics made in third world countries.

Thanks Ray
No I havent yet, but I will go through everything for continuity checks..

Thanks MJ 👍

So I got everything back together again today.
Replaced the regulator and the bulbs that had blown.
Checked all the cable connections throughtout the headset, under the horn-cast and around the, regulator, flasher-unit, and battery.
Replaced the old style fuse holder for a modern mini-spade type fuse holder which is waterproof.
All looks good again and everything works.
I checked the voltage on idle from the Polini Guauge and Im getting 12.9 volts at idle and 13.9 when revving the motor in higher rpm's.

Looks like the regulator was the problem.
Thanks to everyone for there feedback and help…