I did a map quest of my route one time,but I use the bike trail so it may be off by a mile either way,then after a round trip I checked to see how much gas I had left.
After a round about figure of 60 miles,I found I still had 1/4 tank of gas in my Happy Time tank. So I figured 20 miles every 1/4 tank,80 miles a full tank,full tank is 1/2 gallon so total MPG on my Happy Time is 160 MPG.
It's the 70cc engine.
Take into account too that I shut my engine off a lot on my travels to be courteus to the others on the trail and it's shut down when I roll downhill so your mileage would be different if you like your engine idling when not in use.
I also ride with the engine just purring with the 44 tooth sprocket average speed between 10 and 15 mph.