Modern Vespa

Can't you just top up completely the tank? What's wrong with it?
I always fill it up to the top level.

Pholder:

It happens all too often that a problem goes away, only to crop up later. Whatever it is, the fault is stored away in the engine ECU. I'm still leaning toward the regulator.

The engine has three running sensors external to the throttle body: the rev sensor, the water temp sensor, and the lambda probe. It's possible the problem could be the lambda probe.

I have the Techno/Research VDSTS diagnostic interface/software. Here's a link to the User's Guide. Bought from Motorsport Scooters. The interface connects between the scooter's diagnostic port and a computer COMM port. Not cheap, but a great tool and an even better toy.

Here's an update on my 250 GTS. Dealer called Thursday and said it was ready to pick up. They had found "a possibly loose" sparkplug. They had test riden it 17 miles with no problems. I picked it up and started home......it died within half a block. After about 5 minutes it restarted and I drove it back to service. They still have it and I haven't heard from them.

If it wasn't true it would make a great comedy script!

Man. It's just not right, all the trouble you've had with that bike. I hate reading stories like that. I sure hope they find it.

Find another mechanic who at least has a brain-cell for hire. Your present mob sound rather - um - unimaginative.

I'm afraid the nearest one who meets your description is about 2500 miles across the sea.

Sorry to hear about your mystery, but I may be able to shed some light on it. In the spring of this year, my light came on with just around 2500 miles on it. I had to have the O2 sensor replaced. In July, it started doing the same thing, so I sent it in to the mechanic. After a long run of checking everything fuel system related and forming a close relationship with Piaggio over the course of two months, it was determined that the fuel pump was the culprit this time. It seems that there has been a rash of fuel system related issues. Did your mechanic check the fuel pressure, the fuel pump, the whole of the fuel/exhaust system? It has been suggested to me by the owner of the dealership here to use 100% gas from now.

Today also my 2007 vespa 250GTS's yellow engine light lighted up when I went over 6000 RPMs. I also heared a strange sound, around 7000rpms I could hear something that sounded like pocket change in the dryer rattling. Simular to an other member with the same issues. I also contacted the workshop, but they said they could not help as long as the light is not on when the bike have come to stop.

What shall I do ? Is it safe to run the bike ? I have checked: oil, battery, coolant, sparkplug and brakes, every thing where ok.

This sounds like your regulator has failed. Measure the (previously fully charged) battery voltage at high revs. If over 14.6V (especially if over 15V) then your regulator needs replacing. A fairly common fault as reported on MV.

Same problem with my gts250 although not as pronounced. The light came on I would say half a dozen times either at full throttle or at revving down. I did the voltage regulator check and it was within normal parameters. Last time it came on was at the very end of a 360 mile long trip when I was slowing down.

In the beginning I was exasperated by the whole thing but now if the light does not stay on consistently all the time (which has never happened) I am okay with that. When riding in the sun though it is difficult to see whether the light is on or not. I have narrowed my problem down to extended WOT trips. So I try to modulate my riding a bit instead of keeping it at WOT all the time until I reach my destination. Hope this helps.

Poor CAPO and now you see why we do our own stuff. Dealer still sucks.

I'm new to Vespa scooters so bear with me.
I just got a used 250 GTS and after running a new(used) wiring harness, I got the thing running.
While letting it idle I noticed the yellow light come on in the dash.
Thinks to this thread I thought maybe the voltage regulator.
I connected my multimeter and ran it again.
At idle it read over 15 volts and when I gave it gas, up in the 16's.
Clearly too high.
Now is this definitely a case of a bad regulator?
Could I have forgotten to plug in a certain wire to cause this?
Where is the regulator?

Thanks

You'd do far better starting a new thread than opening up one that's ancient. I know nothing about these things but looking at Jim's post a few above it states:

Thanks, I started a new thread.
The reason I posted in these old threads is because on other posts people have nothing better to do than complain about not using the search feature or complain that there are already existing threads that cover this.

Bad voltage regulator?