From where can I get the left side panel for Yamaha R15?

You can get the left side panel for the Yamaha R15 from it's official service center only. Yamaha spares are the least available ones in the market and you can even get the same under your insurance cover. It is advised that you should change all those parts which are at risk as Yamaha R15's aerodynamic design makes the parts rattle if they are loose. You can even use color combination side panels with the original base shade of the body. Yamaha parts are a bit expensive but you can easily feel the quality difference between other brands and Yamaha parts.