@wassy
great work! (y)
btw, I remember doing something very opposite of it. My first car as a student was a year old 1990 Mehran. Being a student and having only 100 rupees per week for fuel really sucked, just to go to college and comeback was my father's plan. Me and my brother used to go around alot and it was not enough for one week, if I remember correctly, pkr 100 used to buy 8+ liters.
I had my own plan, I bought an extra idling jet, resized it and installed and replaced the "speed" jet with it (i used to fine tune my car myself, including spark plug replacement and/or adjusting, timing and even remove the top of carburetor to install/remove jets).
It won't go more then 80km and was slow on acceleration but who needs it in city like Lahore, I was happy enough to get 37~40 km per liter. The only thing that bothered me was the hiccup while starting from a standstill.
Hope my experience can help some guys here who want to save fuel and planet earth 
