Yamaha - Air Shroud, Cylinder Cooling System Component 7HD-E2651-00-00. Overview. This air shroud is one of those parts you don't think about until your engine starts running hotter than it should. It helps direct airflow exactly where it needs to go around the cylinder, especially important when you're pushing long runs or idling in tight spots. From experience, when these crack or go missing, cooling efficiency drops fast. Keeping this piece solid and properly seated makes a noticeable differe