Changing the engine oil in a bike is a simple but important process that should be done regularly to keep the engine running smoothly. Here is a step-by-step guide on how to change engine oil in a bike:

1. Gather the necessary tools and materials: You will need a wrench, an oil filter wrench, a drain pan, a funnel, a new oil filter, and the appropriate grade of engine oil for your bike.

2. Warm up the engine: Start the bike and let it run for a few minutes to warm up the engine. Warm oil flows more easily and helps to remove impurities from the engine.

3. Drain the old oil: Locate the drain plug at the bottom of the engine and place the drain pan beneath it. Remove the drain plug and let the oil drain completely into the pan.

4. Replace the oil filter: Use the oil filter wrench to remove the old oil filter. Install the new filter and tighten it to the manufacturer's specifications.

5. Add new oil: Using the funnel, add the appropriate amount of new oil to the engine. Check the oil level with the dipstick and adjust as necessary.

6. Start the engine: Start the engine and let it run for a few minutes to circulate the new oil. Check the oil level once more to ensure it is at the correct level.

By following these simple steps, you can easily change the engine oil in your bike and ensure it continues to run smoothly and efficiently.