Recall #: 2021-215(Manufacturer recall # M21-012) Models Involved: 2015-2020 Yamaha S-Max Number of Vehicles: 616 Issue: On certain scooters, the primary sheave nut in the clutch could loosen and fall off over time. If this happens, the engine could stall and you may not be able to restart it. Note: You may notice abnormal engine noises if the primary sheave nut comes loose. Safety Risk: