87121-ZVD-000 Rr (6) Mark - Overview. The 87121-ZVD-000 RR (6) Mark is a genuine Honda marine engine part integral to the identification system of Honda marine engine systems. This marking component plays a crucial role in ensuring proper identification and traceability of parts within the engine assembly. Designed to seamlessly fit, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Specific marking part designed for rear applicat