To change the engine oil of a Royal Enfield Super Meteor 650, start by placing the motorcycle on a flat surface and using a center stand if available, to ensure stability. First of all, start the engine for a few minutes to warm up the oil; this helps it flow better, making the draining process more effective. Once warmed up, turn off the engine and let it cool for a moment. Position a container under the oil drain plug, located under the engine. Use a suitable wrench to loosen the plug and let the old oil drain completely into the container. It is important to make sure all the oil is drained to avoid contamination in the new oil. Once the oil has stopped draining, screw the drain plug back on, being careful not to tighten it too much to avoid damaging the threads. After closing the plug, locate the oil filler cap on the engine. Use a funnel to pour in the new oil, following the manufacturer's specifications regarding the type and quantity of oil to use. After filling, check the oil level and, if necessary, add more oil until reaching the correct amount. Finally, screw the filler cap back on and start the engine for a few minutes, allowing the oil to circulate. Turn off the engine and check the oil level again, topping up if necessary.