I have same low fuel average problem with Suzuki Alto 1000 CC
I have discussed this matter with an auto mechanic
He suggested the following
1- Get your carburetor cleaned after detach it from engine.
2- Air intake channel needs to be cleaned. Blocked air intake channel cause more fuel consumption.
3- There are two jets in carburetor. one with narrow nozzle and other with wide nozzle, get wide nozzle jet replaced with narrow nozzle.
Does this help to get more fuel average from Suzuki Alto 1000 CC if so how much?