Verified answer

Yes they have, over the years electronic timing, higher compression and fuel injection were introduced (some places have electronic fuel injection U.S. got carbs) . This all increased the power and efficiency of the engine, not to mention how much more aerodynamic it is today either way you can still push out 60 MPG if you are being a bit careful and it gets better from there. Also the way it puts the power down, changes in gearing meant the engine was more docile at times meaning your saving fuel at lower RPMS. So yes to answer your question the newer models are greater than or equal to the fuel efficiency of the older ones.

Best of luck

You would see a difference in fuel economy when they went from carburetors to electronic fuel injection.

These are relatively fuel efficient. If you can not afford the fuel for a small motorcycle like this, you can not afford a motorcycle. Maybe you should get a 50cc moped.