Unfortunately, within your budget, you won't find a brand-new machine from a reputed Japanese or European maker on the market today. In fact, some of the most affordable big bikes in India, like the Kawasaki 650s, Triumph Trident 660 and the Honda CB750 Hornet, all start above the Rs 7 lakh (ex-showroom) mark, with GST 2.0 partly contributing to this.
If you are open to the idea of a used machine, you will find Kawasaki Z650 / Ninja 650 and perhaps even a Honda CBR650F in your budget. Do bear in mind that you need to be cautious and do a thorough background check on these machines. Because a replacement mechanical part will cost you a pretty penny. And these older bikes also won't be E20 petrol compatible, so that's another factor to consider.

