Modern Vespa

I have owned my '21 Vespa GTS Super 300 for about 6 months. I use it in FL and always fill it with ethanol-free gas. A few months ago I overfilled the tank (rookie mistake #1) while the bike was on the side stand (#2). I cleaned up and kept riding. The next day, the scooter started running really rough, like someone was pinching the fuel line. Shaky starts and jerky runs, check engine light also turned on and would not go out.

After a few days, I'm guessing the gas evaporated out of the EVAP and all went back to normal.

Fast forward a few months. It's 93F and I park the bike on the curb, but I could not find a shady spot. So it sat in the heat for a good 60-75 minutes. I came back to a scorching hot seat and, to my surprise, the bike would not start. Plenty of cranking, but no start. A guy on the sidewalk helps me by testing the spark plug. It was sparking just fine. We then tested the fuel line, check, it was moving fuel. Air also looked unobstructed. After each of the above, another try at starting….nothing. I remembered the articles I read on the EVAP and how they mentioned that hot weather also affected the system. So we looked for the EVAP and followed it all the way to the throttle body, trying to disconnect it. The clamp was a compression clamp and we had no luck as we shook it from side to side and pulled on it. One last attempt to start, and wouldn't you know it….vroom! Coincidence? Maybe, but highly unlikely.

It was right there and then I decided to remove the EVAP system. From all of the research I did, I came up with two options:
Option A: Simply Disconnect and Decommission
There is a great post on this that will help you. The pros is that it is simple, quick, and relatively easy to reverse. The cons is that you have a bunch of dead weight

Option B: Uninstall and Remove the EVAP

Here is how I did it:
You can read it, or watch the video

BASIC TOOLS:
10mm socket
Scissors or cutting pliers
Screwdriver (FLAT)

PARTS (bought at O'Reily's Auto Parts):
Assorted Vacuum Connectors- Dorman #47307
Hose clamps 5/16" - ⅝" (7.94mm-16mm) Master Pro
Rubber Vacuum Caps- Dorman #47396

REMOVAL OF EVAP

STEP 1: remove pet warmer to access engine compartment
STEP 2: remove 2 10mm nuts from the LEFT side of engine compartment
STEP 3: loosen rollover valve/canister bracket by pushing the now-loose screws from step 2 and pulling the assembly down towards floor.
STEP 4: cut hose feeding the rollover valve from the gas tank neck (should enter the rollover valve on the bottom)
STEP 5: loosen the rubber strap around the canister to release it from the metal bracket. You can do this by stretching the strap to create enough slack to unbuckle it.
STEP 6: follow the hose from the bottom of the canister that is opposite the hose that goes to the rollover valve. Locate 1 zip tie that is fixing it to the chassis and cut it. Continue to follow the hose until it meets the throttle body.
STEP 7: use cutting pliers to break compression clamp open and loosen the hose into the throttle body. Remove the hose to expose a bronze "nipple" into the throttle body. At this point, the EVAP assembly can be completely removed.

MODIFYING ENGINE TO WORK WITHOUT EVAP

OVERFILL DRAIN HOSE

The hose cut in STEP 4 above is where gasoline goes in case of an overfill/expansion situation.. If left at this length, the gasoline it can emit will hit the hot engine and can cause an engine fire. In order to avoid this, the hose needs to be extended so that it drains to the ground, as follows:

STEP 1: Thread a hose clamp over the cut hose and insert one end of a vacuum connector into the hose.
STEP 2: Get a length of extra hose that will reach the bottom opening of the engine compartment (I used a piece from the EVAP assembly) and attach it to the other end of the vacuum connector, using another clamp.
STEP 3: once the hoses are secure, thread the hose down to the lower opening of the engine compartment. There is another drain hose I used to attach this one to with a ziptie.

THROTTLE BODY PORT

The throttle body bronze fitting is an intake that no longer needs to be in service. It needs to be sealed tightly to maintain the pressure inside of the throttle body. NOTE: Since the 300 GTS Super is fuel injected (no carburetor), this port needs to be sealed in order for the throttle to work. Other models that are not fuel injected may require a foam filter instead of a plug.

STEP 1: find the vacuum cap that best fits the bronze "nipple". It should fit tight and be long enough to cover the piece.
STEP 2: using a clamp around the cap, secure tightly to the bronze nipple to seal the port closed.

FINISH UP:
Make sure all tools, parts, and debris are removed from the engine compartment.
Reinstall the pet carrier
Start up your Vespa.

CLOSING NOTES:
I plan to keep the parts, just in case this does not fix my issues. I did everything so that I could reassemble it if needed using new hoses and clamps.[img][/img][img][/img]

Couldn't comment on YT because the comments were turned off.

Excellent, thank you !

That should be a part of the Wiki

I was just happy I got the post up. Not sure how to get it into the Wiki.

If your scooter won't start and you suspect the EVAP system, the simple test is to loosen the fuel cap. You may hear a slight whoosh, but in any event a possible tank venting issue will go away. If that doesn't work and the scooter still won't start, you don't have a tank venting issue.

Done.

Like I said, I'm guessing that was the problem and I am not a mechanic. I was giving a little background on how I got to the decision and not preaching the removal of EVAP as a "fix all".

It remains to be seen whether the issue is fixed now that the EVAP is removed. The system seems as useless as an ashtray on the handlebars, so that might be a reason to remove it. Sticking it to "the man" might be a reason. Avenging your father getting run over by a truck full of EVAPs as 4yr old you watched in horror from your swing set might be another reason.
So I am not buying or selling the solution as a fix, but if you have already made up your mind to remove it, then here's how I did it.
That is another good reason to leave the parts intact. You can always put it back if you need to. It's good to have options.
It was fun tinkering w the bike, nevertheless.

I think you misunderstood me. I was not advocating, or criticizing, anything. I was simply commenting that troubleshooting a tank venting issue is fairly straightforward - and requires no special mechanical aptitude.

Deleted

The EVAP system is there to help to keep hydrocarbons from evaporating into our air. As useless as a handlebar ashtray? Perhaps. That might entirely depend on ones views on environmental regulations.

BTW because my car's EVAP system had a malfunction, it didn't pass the last yearly inspection before an EVAP surgery much unlike your own.

Excellent post!

Pump your breaks there fellas! It was a little humor to lighten up the room.

Guess I read the room wrong.

I think I did. Your comment was spot on and true and basically saying "tank pressure was not my issue" as I had originally guessed, and you were right. I am not an expert, just someone that wanted to share with other 300 owners the experience (I won't even call it knowledge) I had with mine. I wanted to give back a little to the community of others that helped me with my issue.

I was trying to bring some levity. Come on..., you know you laughed a little.

I think most of my issues are in fact fuel related, and not fuel system related. The bike sputtered out about three days later and you could hear my screams of anguish 3 blocks away.

As much as my bike sits idle (4-6 weeks) I think I need to be more on top of it with stabilizer, even though I only use Ethanol free gas. We shall see, as the bike now sits at the dealer for a full check-through while under warranty (bad fuel pump would be my only guess).

Nevertheless, this journey started with my overfill experience and the check engine light/rough run (I think I talk more in the video about it). If my bike has a system that is not required by law, that causes the ride to be ruined when a small amount of gasoline bubbles up as the tank is being filled, making it run like crap for 3-5 days w a check engine light on, and I have the choice between "in" or "out", I chose "out".

So I hope others that chose "out" like me, get something useful out of the post. Those that chose "in" should find videos more aligned with their outlook.


Happy and safe riding to you all!
-M

As far as the environment, I think the argument goes way beyond an EVAP system. How much fumes do we let out in the air when fueling our tanks every day? Should lawnmowers have EVAPs? If it is such an effective system, why is CA the ONLY place it is required by law? We can go on for days having that discussion, reaching no conclusion other than whose stamina for arguing is stronger.

I respect your opinion on the EVAP system and your obvious desire to leave one installed and use it. You are 100% right when you say it entirely depends on one's view.

Not once did I say "all of you must follow my view". I, like you, simply stated my opinion and did so using humor to lighten up the discussion.

There is no absolute truth when it comes to this stuff. Only views/opinions. And I get that you want your view heard, but can talk about fun stuff like scooters? Life is too short.

I came to this forum to talk Vespas, riding with bugs in your teeth, and enjoying the great outdoors on a beautiful ride.

I wish you all safe and fun riding! -M

Don't worry. I'm hugely in favour of environmental solutions (despite the fact it costs $205 in CA to smog test our 1984 VW camper) - but this evap crap *as designed by Piaggio* is pretty useless. Properly positioning a simple tank vent line (as Piaggio have done for the rest of the world) prevents nearly all fuel evaporations from reaching the outside.

It's a bad design, pure and simple. Only there to satisfy 50-state import regulations.

While we're on this, the CA 'foreskin' on the fuel pump nozzles causes more spillages of gas with motorcycles then would be the case without it. Cure worse than the disease, yet again.

Because Californias environmental laws are stricter than those of other places. That is either better or worse depending on your point of view. But it is.

I am also certainly not looking for an argument with anyone on this site about the merits of environmental laws, but I am a big one on factual observations. Quite a few other states have basically adopted the California CARB rules for low emission vehicles including Oregon where I live (14 states plus DC). And as Jim observed, the requirement for a fuel evaporation control system on gasoline vehicles imported into the US is a federal requirement.

Old thread I know but we never got word if Andiamo300 thinks this EVAP deletion helped.
So, Andiamo300, did it?

Andiamo300 Thanks for the video. Do you know whether there's any problem with leaving the rollover valve in place between the fuel overflow and the overflow tube that vents to the ground? I'm just wondering what happens if the scooter tips over onto its left side. Will gas leak out of the overflow tube without the rollover valve in place? I might not be understanding what the valve is for.

If you route the overflow hose correctly, there's no risk of fuel escape even without the check valve. Take it to the left side keeping it as high as possible (in line with the overflow nipple) and then down. If it falls to either side there'll still be a high point the fuel won't climb over. That's how the Rest-Of-The-World bikes all did it before the Evap Crap craze took over.

I'm wondering whether this evap canister delete works with the 2023+ E5 ("HPE2") models. I'm looking at a diagram in the current service manual and the canister valve is labeled "one-way electronic fuel vapor purge control valve (controlled by ECU)". I'm worried that because the ECU is involved, removing the valve and canister from the system will mess up the fuel injection calculation or show a check engine light. Anyone know about this?

You raise an interesting question. I don't have an HPE 2 so I really don't know the answer. I will ask the one question I inevitably ask in response to a question like this. How did you conclude that you have a malfunction of the tank venting system on your scooter?

I don't have an issue at present. I'm considering the canisterectomy as a preventative measure, having heard that overfilling the gas tank can lead to performance issues, or even prevent starting, when gas saturates the material in the canister. I try to be careful when filling the tank, but accidents happen. I'm wary of disconnecting anything electrical, though. I had thought that the evap system was passive.