I have Yamaha Gladiator Type SS Red-silver colour, for how much should I sell my bike?

Your Yamaha Gladiator SS has a market price of INR 22,000-24,000 as the model was discontinued and a new, SS 125 was launched with identical specifications. You can get a maximum of INR 26,000 if you try to sell it directly, instead of getting with some bike dealer. Your low reading on the odometer will benefit you and the bike would easily get sold for the same. It gets a 123 cc engine, producing 11 BHP and 10.4 NM of torque. The disc brake in a 125 cc bike would be a plus point for you. Its design is better than any other 125 cc bike and i would even suggest you to keep the bike if you are planning to opt for a new one. You won't get any extra features in a 125 cc bike, if you ever go for it again.