 One of the most popular category are the 150cc four-stroke fuel-injected class and may have engine power output ranging from 24 to 32 horsepower and can reach up to 180 km/h.Most of the motorcycle competing in this class are Yamaha T-150, Honda RS150R, and Suzuki Raider 150.

Notable underbone road racing series in Southeast Asia country are Malaysian Cub Prix and Indonesian Oneprix and MotoPrix Series.The highest level for underbone road racing class are held by Asia Road Racing Championship under UB150 class, from which only production underbone motorcycle with a maximum of 150cc engine displacement may compete in this class, hence the name.