For You should refer to the owner's manual or contact a Royal Enfield authorized service center for the most up-to-date and accurate information regarding the recommended engine oil for your specific model and year.
It's also worth noting that there are various reputable brands available in the market that produce high-quality engine oils suitable for motorcycles. Some popular brands known for their motorcycle oils include Castrol, Motul, Shell, Mobil, and Yamalube, among others. When choosing an engine oil, look for one that meets the necessary specifications and is formulated for motorcycles to ensure optimal performance and protection for your Classic 350's engine.