Yes, Royal Enfield motorcycles are predominantly known for their single-cylinder engines. The majority of Royal Enfield models, including the popular Classic, Bullet, and Himalayan, feature a single-cylinder configuration. The single-cylinder design is one of the distinctive characteristics of Royal Enfield motorcycles and contributes to their unique sound and riding experience. However, it's worth noting that Royal Enfield has recently introduced the Continental GT 650 and Interceptor 650 models, which feature a parallel-twin engine configuration.