I hope I'm not the only Schussel, who constantly forgets to turn his fuel valve and therefore has a very bad start behavior. In addition, there's also problems with the landlord, because the beautiful leaves in the long dark stains on the concrete. We needed a fully automated solution.

I've thought about solving a problem and only experimented with electronic fuel taps, as are also used in recent Vespa models are used, even if they have a reputation to keep very long. I am also disturbed by the idea that a solenoid valve useless while driving consumes power, because my alternator is anyway quite shaken. So I've copied the thing with the negative pressure control at the cheap Chinese scooters hardware store. But where to get a vacuum or other Vespa scooters with carburettor? It's simple: the carburetor. We must tap into the area just between the carburetor and the engine block itself, or the intake manifold. Since the connection is however quite difficult to access, I have decided to drill the back of the carburetor body. But it carefully! If the tap is leaking for some reason, the engine can suck in air leakage, resulting in a sporadic and independent spin up in the booth. Is also quite embarrassing when you are standing at full speed at the traffic lights

The vacuum valve design in flying (! Not for direct tank mount) is quite reasonable to have the dealer (about 6 €) and has three ports: input, output and vacuum control. The latter is the small port on the lid and inlet and outlet are marked by an arrow on the housing. If so now is drawn to the controller is switched from input to output. As we tapped the vacuum at the carburetor, is so only with the engine running, or after the first Ankicken already passed through.
Now back to pick off the carburetor. In order to attach the tube well, I have an old bleeder screw for brake calipers concerned with M6 thread. The lower part of the nipple can be cut with confidence because we are only about 4mm screw for fastening the intake need. More I did not want to leave it, otherwise maybe the flow in the carburetor could be confused. Then make an appropriate place a 5mm hole and cut a M6 threaded into it. It pretty much fall in Alu chip, which should be very carefully blow out of the carburetor. If even the smallest residual is left, it can block the internal mechanism. Before screwing the nipple I have the thread wrapped with Teflon tape for plumbing work to the place and yes 100% safe to know closely. Then reassemble the carburetor and inject valve with inlet and outlet into the fuel line between tank and carburetor. The vacuum control system is then only to the bleed nipple (keep cables as short). The original mechanical fuel valve on the tank will of course continue to work, you need, too, if one expands the tank once.
My light-off behavior has improved dramatically, but the residual gas in the tube can dissipate over long periods of time. Then you have to stop kicking two to three times, so that the box starts up again.