Okay - at home without purchasing more parts...
I am looking at the pictures you posted and it looks like you have Dellorto SHA carburetor. If it is bigger then a SHA14:12 then you need to open the inside diameter of the intake pipe to the same size as the carburetor. If it is a SHA14:14 then you need to open the pipe to 14mm, SHA15:15 needs 15mm and SHA16:16 needs 16mm. Make sure when the throttle grip is twisted that the gate inside the carburetor lifts all the way up out of the bore of the carburetor.
If you remove the cylinder from the motor and check with the gasket between the cylinder and the carter that the transfer passages line up. Where they are not aligned you need to file away the excess metal. Do this slowly and carefully and ensure no metal falls into the motor.
You can also adjust the port timing of the motor. You would need to purchase a high performance reed set so the motor can flow more air through the intake if you port the motor. There is a thread already on the method of porting here http://mabecanemobylette.freeforums.org/viewtopic.php?f=24&t=1047
. Use the method of how to port but the numbers for a AV10 motor will be different. For a SHA15:15 or SHA16:16 you could port your transfer ports to 124 degrees and the exhause 180 degrees. Then check the cross section area to ensure you are flowing enough through the port windows.
For the ignition you would want to adjust the timing to give you somewhere between 1,5mm and 1,0mm before top dead center. This you will need to experiment with and let the motor tell you when you are at the right setting for the ignition.
ALWAYS change your jetting in the carburetor after you do any modification on the motor. Even just removing the air filter can change the demands for fuel in the motor. If you do not check and react to this need you will seize your motor.