Those who have little 2-wheeled toys based on homogeneous traffic flow has a slightly tuned, knows the thrill of standing at the traffic light next to the police. If it is then also stopped (worst case), it is just beginning to be really funny to. Since the classic work on my speed limiter old Vespa of course not, so I had to come up with another way to protect myself from these situations. The idea was that you could potentially reduce any engine, if one narrows the outlet of the exhaust. The idea is not new, as many sports bikes already have designed a dynamic, automatic exhaust valve, which controls the back pressure to deliver to the engine in the rpm range the optimum back pressure. So I grabbed at eGay a 12V power outlet control for a Honda NSR, I wanted to use for an electric narrowing my elbow.

The servo does nothing more than a corresponding reduction two Bowden cables back and forth alternately herzuziehen. Although he is actually running at 5 cables, 3 of them but their only purpose the control device, the position of the motor delay. This I did not need and they have therefore removed. Either by cable or try to unscrew the housing and just follow the cable to the electric motor.
The narrowing, I then realized with a ball valve from the hardware store. This form of the faucet is in a position with only a rotation of 90 ° between full forward and full blocking switch. There are all sizes him, so that for each exhaust or Krümmergröße probably what should be there. The bottom bracket is made of Teflon, however, and considers it is not excessive temperature. Teflon melts at 327 ° C for which the hot exhaust gases of up to 700 ° C is actually too little. In practice it works but still quite good, because the seal is not exposed at the edges of the full temperature. In any case, my one-way throttle works freely today. I saw this ball valves with bronze seals but even that would naturally be preferred. The housing is made of nickel plated brass, and therefore can not be welded directly to the manifold. Right next to the ball valves but depend on the same hardware store the matching connectors with threaded steel. This I have screwed left and right easy with Teflon tape to the tap and then there could weld on my elbow. In my Vespa PK50 was behind the wheel arch, where the manifold goes over the tire on the left a little space to accommodate all. So if you do not currently have about the subject matter and shall, in the Vespa, it is not visible. Here I had then also the possibility that the switch cable to pull at the side door to house the electric motor. I proceeded as follows: ball valve next to the elbow held interfaces marked out, elbow extended and in a vise clamped such that it extends from its position and length after being cut does not change, then cut and tap wrapped (!). Am I welded ball valve even a small angle plate to secure the screws for the snakes. The stroke I have set that in motion the stop cock still remains a bit open so the engine will only cut back without completely going out. Must be screwed off the top of the red handle with only one parent, and this is the round plate screwed to the servo motor. Fits right away, without modification !

Now it goes to the electrical part. Because I want to use the throttle so dynamically During the trip, I've hidden under the handlebar a polarity reversal switch (toggle switch with 2x 6 pole A and the center position) built and connected in front with a 3A rectifiers on the power board. The rectifier is essential for a Vespa without a battery because it is indeed a direct current motor, and that we must reverse the polarity so it deliberately. Both are there in the radio shop you trust, how to connect the pattern you see in the picture.
Now simply pull the cable from the handlebar clamp to the side and attach the electric motor. On the video below you see the throttle before the installation in äktschn