A properly tuned engine and carb and perfectly time ignition can do 16+ in lhr city, 21+ on highway (even on 30+ yrs old engines) but depends how do you define a PROPER tune-up. Unfortunately, chhotaâs and pappuâs and sheeedaâs that later became USTAADS can take things apart, then fix them back up but actually donât know the science of the important things mentioned above. My 85 SS80 does 14+ in multan city, if soft on gas paddle, 20+ on highway, AC can reduce a Km or two, where as the piston rings are 50% efficient. I tune it up myself Alhamdulillah.