Modern Vespa

O.S.

Dunno these strange numbers, but here 1 litre 98 costs 2e. (=2,013e)

$4.80 US = 4.16e. He bought a half US gallon (1.89 l) for $2.40 or about $1.27 a liter = 1.1e

Have you removed the green plastic ring in your filler tube yet? Doing so will reduce overflows significantly!

It's easy to do. Just screw a screw into the ring with a screwdriver (I didn't pre-drill a hole), and then pull out the ring by the screw using some pliers.

Removing the plastic ring also allows you to see and hear the fuel reaching the top of the tank more easily.

I think the ring is only there to reduce evaporative emissions.

Since I removed the ring, I've had zero overflows!

No - the ring is there to stop diesel being inadvertently pumped in, as diesel nozzles (in Europe at least) are a larger diameter. Also the colour is significant, as in Europe the petrol ('gas') pump lines are green, while the diesel ones are black. That's the reverse in the US of course.

I've heard this advice before. Honestly - I tried a pull on that green thing - but....the whole darn tank, cap and threads are so sketchy, I decided, with my luck, I would snap the neck and require a new tank.
90% of the time, I fill with a gas can at home. "Pour, look, pour, look w/flashlight, pour"...turn key on - see how I'm dooon. Stop if all bars.

Frankly - fills and rethreading the gas cap* are my only two gripes about this scooter. I can live with it - and have, quite happily for 9 years!

O.S.
* yeah, tossed the plastic OEM cap soonest! tank and cap hated each other - or me. We never worked it out. Bought the nice billet Vespa cap. Some better....not perfect. Cheap plastic tank, neck and cap. Seen better threads on my Kroger milk jug!

Finally got a billet cap from AliExpress. Big improvement. It appears that the OEM cap and tank are molded from the same material. Makes them want to stick instead of slip easily.
Green insert does not help with filling tank. But it does have the "fill to here" tab. I understand overfilling is to be avoided.

OFG

That was my thought, too!

O.S.

Billet cap threads vs plastic tank threads: Billet wins every time.

Take a lesson from the rednecks - just stuff a rag in it, and be very careful if you smoke.

I get your fear, but the green thingie popped out pretty easily for me.

I replaced my gas cap long ago with a billet Vespa one too! So necessary! The plastic cap was darn near impossible to remove most of the time. The billet cap is no problem.

The shock adjuster wrench in the tool kit will loosen a stuck cap

Sort of like digging a tool out of your trunk every time you put gas in your car. No thanks.

OFG

Is it just the Libertys that suffer from this? I've not encountered any fuel cap problems with any of the dozen or so Piaggio scooters I've owned.

It really does have to do with the plastic used for the tank and the cap. I'm no expert on plastics - but either the tank or the cap, or both are made from some sort of 'grippy' nylon-like or plastic substance.

I think I complained about this in one of my early Liberty posts - in 2017~!
"Great scoot - lousy gas cap!" Plus - I always suspected the threading on the neck of the tank - give the quality of that thread on the tank a "C-".
I carefully watched Robot unscrew one on a video - he had to get a pretty good grip to get it off. As though it was very tightly screwed on.....but even a modest tightening will seem to lock the cap and tank neck.
Are all Libertys made in Vietnam, like mine?
O.S.

I greatly prefer the fuel tank mounted under the floor board on my Piaggo Fly. Easier to fill, doesn't have that green filer neck and has more room under the seat. I wonder why they didn't keep the feature on the Liberty.

same , I suspect operators not keeping the cap level and or even turning it slightly backwards to ensure threads line up before screwing it down. only takes a 1/4 twist backwards.

But it wouldn't be only Liberty owners in that case!

The Vespa tanks I've worked on all had the the >HDPE< stamp on them. I believe that stands for "High Density Polyethylene". While the tanks have been robust, the ones with cap issues tended to have one or both of the following issues:

1) The casting flash wasn't fully removed from the filler neck section, leaving a protruding ridge of plastic for the cap threads to bind on.

2) The threads had been damaged during a prior removal/installation of the fuel tank. I noticed this latter issue specifically with GT/GTS chassis. The LX chassis has a clearer path for tank removal and I don't believe the Liberty has any stamped steel chassis components that the filler neck has to pass through during removal or installation.

My recommendation would be to check the threads for casting flash or damage and lightly dress any flash off with a fine hobby file.

Or get an aluminum cap.

OFG

I am so glad to hear that others have the same problem with taking the gas cap off. My cap gives me a hard time every time.

I'll look for flash or other errors in the actual threads but buying a metal cap seems like a great idea to me. Now the cap can be the boss of the filler neck, and we won't be having any more tug-of-war ties.

I'm also glad to hear the green filler neck restrictor isn't necessary for the scooter to function. I'll remove it and see if that doesn't help with the overflow issue.

Using the shock adjuster wrench seems like a good backup plan, but I doubt I'll remember it if the cap is stuck on so much so that I can't remove it by hand.

Just don't overfill.

OFG

I made a tool to remove my gas cap with very low effort (3D printed). It's orange to make it easy to find in the pet carrier. Since I have to pop the seat anyway, it is minimal trouble to find.

I have 2020 liberty with underseat tank & MP3 with floorboard tank
Both caps will seize up
The MP3 tank will make me take a knee to get the cap off
it's definitely easier to cross thread the low tank.
The plastic on tank, cap & gasket are soft.
Crank either one tight on a warm day & try to remove when temps are lower. Bam my wrist will give a pop & I'll dig out the toolkit & hook wrench

Further Liberty has the green insert & the MP3 doesn't
No difference except the geyser of fuel if I go too fast is a bit higher on the MP3
I go slower on fueling the Liberty due to the smaller skinny wrap around tank, the return wave seems faster & gets into the pet carrier.
MP3 any mess is low & under the door

My 2017 Vespa 300 is barely ok, someone with weak hands could have real problems.

The other Piaggio products I have/had are/have been totally fine.

Seven years ago - eBay, @ $12
(I've seen the plastic OEM cap for sale by dealers for $34!)

I ride a 2021 Liberty 150. When the fuel light comes on, I put exactly 1 gallon in the tank. Doesn't overflow and shows full on the gauge.

Gary

Hey thanks!
That's good information.
I once rode all the way home from my coffee village with that light on. A nervous ride!
O.S.

I drained the gas tank on the ET4 150, to install new fuel petcock. At 1/2 tank on gauge, drained 1.3 gallon.

I sold my LX and my GT. Never had this sticky cap problem on either.

Then I bought a Liberty. Jammed cap every time! It's annoying, and I don't think operator error. (Though it admit when I first heard of this I assumed the same .)