here's some pics of my setup.
As you can probably see in this setup the closing of the ball valve only controls how much air is brought through the jar by reducing how much it let's through creating a bit more vacuum through the jar.
This one is of the jar itself, as you can see with this image the pipe in it has about 50 1/16" holes. And i made it so that they go around the pipe in a spiral to reduce the amount of vacuum needed to pull air through it.
The 50 1/16" holes are only about half what is needed to hit the same air flow as the 3/4" pipe, but i did this to better control the throttle of the scooter.
I found out with this setup that the bigger the bubbles coming out of the pipe the rougher the idle. I had just the 3/4" pipe going into the jar and at idle it would pulse badly with the bubbles that were coming out of that size a hole.