I have both an 09 Ninja 250 and a 2011 Honda CBR250R. As stock bikes, the Honda kills the Ninja on fuel economy. Check Fuelly. I can average 87mpgUS at 65mph on the CBR250R and the best I can get with the Ninja is 66mpgUS. Some of the small 125cc air cooled Hondas from India can get 130mpg but only have a top speed of 65mph whereas the CBR250R is a dream to ride all day long in the rain at 90mph. It is a real bike, is available with ABS and only costs $4000 brand new with great factory financing.
.
Gas Mileage CBR250r - Honda CBR250R Forum : Honda CBR 250 Forums
.
Honda CBR250R MPG Reports | Fuelly