Modern Vespa

Lately my GT 200 has not been running well in the hot weather. I decided to do some maintenance; oil change, new spark plug (Denso IU24) and remove that pesky EVAP system. After reviewing the Modern Vespa Wiki I found my system had an extra hose that was not mentioned in the EVAP removal/mod tutorial. My engine has two hoses; one that is described in the tutorial and one that is not. The hose in question is after the carb. With the engine running the "other" port pulls a noticeable vacuum where as the port described in the tutorial has nothing noticeable. The port that pulls a vacuum was covered with a small cloth and a hose clamp. I think both ports need a filter but temporally I left the port on the carb alone until after I hear some suggestions on how to proceed.
Has anyone run into a similar experience? If so; how did you fix it? What did you do with the overflow vent in the neck? I was thinking about plugging the hose off the neck but had concerns about the vapor pressure in the tank in these hot dessert conditions in Albuquerque. Thanks in advance for you help, ideas, and suggestions.

This post addresses the overflow port in the filler neck.

If you opt for this disconnect be careful where you end up placing the end of the hose to drain off any overflow of fuel you don't want any spent fuel to come in contact with an ignition source. Also be cognizant that a slight overflow may result in fuel draining out onto the ground. Need to make sure you clean this up as it can be dagerous for anyone who walks or rindes up on same.

I've had situation where a slight overflow resulted in fuel going down the hose and drained off on the surface below my scoot at the gas station. Fortunately when I approached the attendant for clean up material they said they would take care of it.

Fuel overflow hose disconnect from roll over valve (GT200)

Also included a complete schematic.

Hope this helps.

It's "after the carb" in the intake. That "noticeable vacuum" is a intake leak -- your motor is running lean. Do not ride it like this.

If your evap system has been completely removed need to cap/plug this fitting.

Thanks for the info! Good thing I waited before I took the scooter out for a long ride.

I am totally confused. I have disconnected the hose that runs from the neck of the fuel tank to the Evap system and have rerouted that to a hose that dumps out by the rear wheel. This gives open air to the fuel tank and dumps any overflow when filling onto the ground if I mistakenly overfill the tank. I have also disconnected the hose from the evap system that goes into the top of the carb and have fashioned a simple filter to let air be drawn into the carb without dirt. The scooter runs just great except for being difficult to start when cold like sitting over night. I haven't done anything with the "after carb" hose connection. Is this connection something that needs to be plugged? Am I possibly drawing air through this hose and causing it to be too lean? The scooter runs really strong and starts instantly any time except for when it has been sitting over night. It actually seems to start well even then if it has less than half a tank of fuel but not when the tank is full or near the top. Any ideas?