Modern Vespa

Hi everyone! I've been troubleshooting this neglected 2007 GTS 250 for about a week and have not been able to figure out a starting issue. I have scoured this forum full of helpful information but to no avail. The scooter has just under 5000 miles so its been sitting for some periods of time. So far this is what I have done to try and fix it.

- New Iridium spark plug
- New Battery
- New Spark plug cap
- New Air filter
- Cleaned and inspected injector spray
- Cleaned throttle body and bypass
- Dumped fuel and replaced with a new batch
- Tested voltage regulator seams fine but hard to keep running long enough to get a prolonged reading

Other unrelated maintenance
- New coolant
- New gear oil
- Oil and filter and filter change
- New Belt
- New rollers
- New exhaust bushing

I have uploaded a YouTube video of the start up below.


Thank you in advance hoping one of you scooter wizards knows my issue or have dealt with something similar before!

Carefully inspect the inlet manifold between the throttle body and the head for splits and leaks. Even a small one can cause problems.

Fuel pump or fuel pump related. Check all the lines, filters, etc.. before springing for a new pump.

Thanks Jim for the great suggestion! I actually took the inlet manifold off this morning however, I was mainly looking at the injector. I'll go back and take a deeper look at the manifold itself!

What Jimc said is an even a better suggestion. I do think it is a fuel/air problem rather than electrical. Is it possible that this scoot was on a recall list?

Thanks Tierney, I am hoping to avoid a new fuel pump as it looks like and more involved but hey, it's a great excuse to check on the valves ; )

Just missed the recall unfortunately !

I doubt it's the pump, as it's obviously working to provide a good squirt to the injector.

I suppose it could be a weak coil, or poor connection between coil and the HT lead.

I took apart the inlet manifold and gave it a compete clean but did not find and splits or cracks.

I am thinking about ordering a new coil and HT lead as Jim suggested. Are there any other quick and easy parts I should add to the order as it take up to a week for parts to get here?

Find a fuel pressure tester, as it sounds very much like a low pressure running. Most garages will have one as its nothing unique to bikes, let alone piaggios.

Thanks Cheeky! I read quit a few of your comments this week trying to track this issue down.

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Must have been mighty old as I've not been about for the past 10 years... But fuel pressure would be top priority to check.

Hi CT, glad to see you're still around!

Are you still working on bikes?

My '06 was doing this at the beginning of the riding season. It turned out that it was my old battery. It would go through all the motions of starting EXCEPT that the fuel pump wasn't priming before I tried to start it. It would turn over then die. A new battery sorted it out. I know you mentioned that you installed a new battery but I'd try another just to rule it out. I was convinced my fuel pump was gone until my mechanic swapped the battery out. Can try jumping it off of a non-running car battery.

Good luck.

w.

Hello, I left bikes to go into Yamaha 2 stroke outboards for the offshore rescue industry... Now doing agricultural engineering, so tractors, quads, SxS and the like...

Eldest is now 16 and she's brought a do it up project for the summer, so looks like I'm back full circle. Lmfao.

I'm channeling Judy today by suggesting fuel line replacement. Looks like Tierney beat me to it.