Yes, you can use 20W50 grade engine oil in a Royal Enfield 350X motorcycle. Royal Enfield motorcycles typically have engines designed to operate with heavier viscosity oils, and 20W50 is a common grade recommended by Royal Enfield for their motorcycles, including the 350X model.
The first number (20W) represents the oil's viscosity at colder temperatures, while the second number (50) represents the viscosity at higher temperatures. 20W50 is a multi-viscosity oil that provides adequate lubrication during both cold starts and normal operating conditions. It offers good protection for the engine components, especially in warmer climates or during hot weather conditions.
When choosing engine oil, it's always best to refer to the manufacturer's recommendations. You can consult the owner's manual or contact the Royal Enfield customer service to confirm the recommended oil viscosity and specifications for your specific motorcycle model, as they may vary depending on the year of manufacture and regional requirements.