On CD 70 one screw is for idle adjustment and the other is for fuel/air mixture.
My question is that how to adjust the fuel/air mixture?Does tightening it make the mixture lean or rich?
search previous posts or google it.. topic has been discussed already
https://www.pakwheels.com/forums/bikes-3-wheelers/165529-self-tuning-your-bike-carb
This is the thread with all info.