Correct me if i am wrong in your case. All thise who think their bikes giving 35 or 45 or 55 km/L mileage. It's exaggerated by companies. Your odometer is kept fast or loose on what purpose companies know best. But according to GPS speed it is always 5-10 kmpHOUR speed didference. if your speed is 70. It will be 60 in acutal. But meter will be running at 70 which means if you think you covered 100 km on bike. But actually you covered 90km. ( 45km if you covered 50km)
My bike is giving 50km/L on GPS speed. I have the best mechanic. My bike already going to achieve 50000 km mark soon. And this is the mileage. And i have reduced my odometer speed to almost accurate as GPS. 1-2+- kmph difference.
But in cities lots of problems. Petrol pump frauds. Less quanity in 1 liter and bad petrol give bad mileage to my bike.