I bought yamaha sz-r on 1st January, 2011. It was nice till this moment. Giving 50-55kmpl under economical drive. If you ride it rash, the mileage would be nearly 35-40kmpl. Go for it if you really need a 150cc economical bike that would satisfy good handling, powerful pick up (but not the level of other 150cc segment bikes), smooth engine. It is suitable for the people who really need 150 cc bike with economic conditions. The cons of the bike is, it will reach its top speed(110kmph) with some time period where as other 150 cc bikes can reach it easily.
The mileage will vary very less if you ride the bike very rash. Thats it.. Other things of this bike is really satisfying our normal requirements. Whatever product you buy, make sure you are doing the service, oil maintenance, speed maintenance properly. Yamaha & Honda engines won’t let you down.. Happy riding..