Hi Wuming,

Stats for the trip I did with CrazyCarl on QingQi QM200GY Dualsports. The gas was a bit more expensive back in July, but this should give you a pretty good idea:

Distance = 4,650 Kilometers (2890 Miles)
21 Gas Stops
Average Distance Between Fuel = 222 Kilometers (137.94 Miles)
Average Fill Up = 7.398 Liters (1.95 Gallons)
Average Gas Price = 6.07 RMB per liter ($0.89 USD per liter) = $3.37 USD per gallon
Average Kilometers Per Liter = 29.47 (69.32 Miles Per Gallon)
Total Fuel Cost = 900.00 RMB ($132.00 USD)

Can't beat that.... these bikes are very efficient on fuel.

Cheers!
ChinaV