Modern Vespa

Hi all
This weekend I decided to do the evap bypass
I followed the instructions in what I consider the definitive thread so that I did not have to cut the hoses but just disconnect them from the evap cannister, block the one that goes to the throttle body, and extend the one from the gas tank to avoid any gas spilling on scooter parts. How to remove or disconnect the Evap Sys. from GTS/GTV

When I was done, I thought about it and wondered.
Could I have just disconnected the overflow hose from the gas tank and blocked it off, and then ran a hose from the tank under the scooter?
That way I would not have had to deal with the crazy clips and be able to put it back to stock in seconds with no hassle. ?

Yes, of course, it's what I did!

For those following this discussion - one thing to keep in mind. That line leading back to the carb or injector from the charcoal cannister is treated differently in carbed versus FI bikes. The connection into the carb should be left open (some recommend using a small filter), while the connection to an injector (as with a GTS) should be blocked.

I always have mixed emotions about these evap system discussions. Most of those disconnecting the system have never had trouble with it, and a fair proportion of those who think the system has failed notice no improvement after it is disconnected. Can the system fail - certainly. Should it be repaired or disconnected if it does - certainly. Should everyone run out and disconnect the system just in case - I'm not convinced. I have had 8 Vespa and other Piaggio scooters with this system. I have never experienced a tank venting failure.

I have no experience with EVAP systems. Checked out some youtube movies to understand more about it. Clear now what it should do and how it works.

The question I have is whether it makes any difference to mount it on scooters and motorcycles in general considering their negligeable share in total fuel consumption.

Anyway, my 2012 BV does not have it and our 4 cars are all diesels. I guess diesels don't need it considering the low volatility of diesel fuel.

As jimc said yes. I don't know about the GTS but on an MP3 you get a sizable area back under the seat if you remove the canister. Big enough for a small tool kit or spare gas bottle.





All pics here MP3 250: Removal of the evap canister and roll over valve

what the hell did we do BEFORE government step in and mandated this system? Wy don't lawn mowers have it or weedeaters? I don't see them on boat motors. guess government needs to mandate all those classic muscle cars and old models t's to retrofit

There's a noticeable difference if you put your scooter away in the garage after a ride. With evap, you get the mooing sound as the fuel in the tank gets hot beside the hot engine, expands and pressurises the fuel fumes. Without evap, you get a very strong smell from those fumes. Outside in the open air you might not notice those fumes, but they are pretty strong and can't be good for any creatures to breathe.

So although I think the system is a crap design, unless you have problems with it it's probably best left alone for everyone's sake.

I used this technique after Rocket stranded me several times.

It sputtered until it wouldn't run, then wouldn't restart for hours.

Once I had to push it three miles home.

Another time a mile and a half.

After disconnecting the canister it became a dependable scooter again.

The success of doing this had me repeating the process on my other two GTs.

Rocket had well over 60,000 miles on it when I did this.

Bill

nope

have you seen the evap systems they use on the airplanes? or the cruise ships? or the locomotives? what about the ones on those 18 wheel thingys?

nope

nope

I take it you know that all those "thingys" you mentioned run on kerosene or diesel which have fairly low volatility, unlike gasoline.