Honda2Wheelers — mileage

I am hemant chhajed purchased a Honda dream neo on 5.7.13 frame no me4jc623fd8010871 engine no jc62e81010882 dealer code 210001 company advertising that bike will give mileage 74km dealer also said it will give 74 to 80 km but unexpectedly the bike gives mileage 50 km. in this situation I informed the dealer several times they checked my vechicle three times but problem not solved I have to travellel daily 50 km . I am requesting you to solve my problem or replace my bike