Yamaha Tensioner Assembly 6CB-11590-02-00. Overview. The Yamaha 6CB-11590-02-00 Tensioner Assembly is a genuine OEM component designed to maintain proper tension on the engine's timing chain system. By keeping the timing chain correctly tensioned, this assembly helps ensure precise engine timing, smooth operation, and reliable overall performance.. A properly functioning tensioner prevents slack in the timing chain, which could otherwise lead to timing inconsistencies, excessive wear, or potenti