A medium and large Phillips screw driver
A medium or small flat head screw driver
2. Remove 4 screws indicated by the arrows and lift the spoiler (stock shield) off.
2. First picture. Under each side shield there is a screw that fixes it to the back shield. Second picture. At the top rear of each side shield there is another screw fixing it to the back shield. Remove these screws. (4 total)
Note: in the second pic just to the left of the arrow it shows an empty screw hole. The screw that goes there is purely cosmetic and should not be removed. Don't know why Piaggio removed it but don't. Good catch http://modernvespa.com/members/bravotwofour
3. Remove the two hex screws and one Phillips head screw indicated by the arrows. The side piece will slide forward. Gently lift and move forward. Caution: there are some easily breakable plastic tabs on this piece.
2. Disconnect the center light terminal and remove the support.
3. Remove the two Phillips head screws that fix the bottom of the headlight support indicated by the arrows.
4. Remove the two Phillips head screws that fix the headlight support to the back shield indicated by the arrows.
5. Tilt the headlight support forward and remove the terminal clips on both the high and low beam bulbs on each side.
6. You can further disassemble the headlight assemblies if needed by removing the screws indicated by the arrows
Other chassis disassembly information can be found starting on page 323 of the service manual here (UK source):
or here (US source)