Ok folks, went out for a great ride this weekend. Began to a little concerned about gas since the trip out was 28 miles. On the way back I turned it off on down hills (I was in the mountains of Washington) Well I think I did that for about 3 miles. As I was pulling into the campground I ran out of gas. Turned on the reserve for the final 5oo feet!! So, I think the stock tank will do about 50 to 53 miles without coasting, not sure about reserve but cannot be much. I also was easy on the throttle to concerve gas. Moral is to watch how far you go on the stock tank. Better option is to get a bigger tank.