Not on the bike, but I check it on the car sometimes.
short of filling up and running it empty what are the ways to find your mpg? Now i get low to mid fortys depending on my mood.
Set your trip meter to zero when you fill up. Then the next time you fill up, whether you ran almost empty or not, divide the miles from your trip meter by the # of gallans you put in the tank. Reset your trip meter to check again the next time.
If you don't have a trip meter, then you have to write down the number of miles on the bike at fillup and then do the math at the next fillup to see how many miles you rode/drove. Again, divide that mileage by gallons to find gas mileage.