The Royal Enfield Classic 500 Stealth Black BS4 model is equipped with a single spark plug, despite the vehicle manual mentioning two spark plugs. The reason for this discrepancy could be due to different variants or model specifications within the Classic 500 series.
Manufacturers sometimes provide a single manual for multiple variants of a model, and certain specifications may vary between those variants. It's possible that the manual includes information about other Classic 500 variants that have two spark plugs, while your specific model, the Classic 500 Stealth Black BS4, is designed with a single spark plug configuration.
To get accurate information about your motorcycle's specific configuration, it's recommended to consult the official documentation provided by Royal Enfield or reach out to their customer support directly. They will be able to clarify any doubts and provide the most accurate information regarding your motorcycle's engine configuration.