PIAGGIO MSS FLY 50 4T WORKSHOP MANUAL Pdf Download. Page 65: Inspecting The Clutch Drum, Removing The Clutch MSS Fly 50 4T Engine Inspecting the clutch drum - Check that the clutch bell is not worn or damaged. - Measure the inner diameter of the clutch bell. Characteristic Clutch bell diameter/standard PIAGGIO FLY 50 4T 4V MANUAL Pdf Download. - manualslib Fly 50 4t 4v Chap. 03 Maintenance.. Page 30: Engine Oil Level Engine oil level (03_01) In 4T engines, the engine oil is used to lubricate the distribution elements, the bench bearings and the thermal group.