Hi Deepu11007, the following tips are low cost easy to apply/install and guaranteed to give you better gas mileage and a smoother running bike. The average motorcycle gets 35-40 MPG. saving .2 gallon of gas could save you a 6-mile walk. 125cc scooters have been known to get 115 plus MPG
1. Proper tire inflation as per MFG. specifications wheels should be balanced and spokes tight.
2. Oil and coolant levels maintained at full marks, low levels produce excessive heat that causes the engine to work harder and reduces efficiency.
3. Keep extra weight to a minimum.
4. Take off from a dead stop should be smooth and easy throttle applied avoid excessive throttle snaps.
5. Smaller windshields get better MPH than large ones, wind resistance increases as a square of the speed at which you're traveling. So, for example, at 70 mph, wind resistance is double what it is at 50 mph (70 squared is almost twice as much as 50 squared). Thar will drastically reduce your mileage. Keep that in mind while biking.
6. Keep idle time to a bare minimum or turn off the engine.
7. Re-jet carburetor with a smaller main and mid-range jet.
8. Keep chain/belt properly adjusted.
9. Avoid quick braking, hasty acceleration, high-speed driving, try driving the speed limit and keep a constant speed.
10. On long trips use freeways or flat straight stretches of highways rather than city or rural routes avoid hills and mountains when possible.
11. Keep your engine clean, dirt and grease/oil hold in heat.
12. A full-face helmet is more aerodynamic than other types of helmets. Any other clothing that decreases your aerodynamic should be reconsidered.
13. Any unnecessary bling on your bike is going to decrease fuel efficiency.
14. Use high-quality fuel using low-quality fuel can cause sludge in your fuel injectors.
15. Keep warm up time to a minimum get off the choke ASAP.
16. Motorcycles run best when their engines are maintained, and that includes making sure the air filter is clean, the spark plugs are fresh, the fuel filter is free, and the timing/valves are adjusted.
For more information about your issue, please visit the websites below. Good luck and have a nice day.