Valve clips for 50cc GY6 139QMB engines These valve clips are used on a wide variety of scooters and ATV brands and models that have a Chinese built 50cc GY6 139QMB engine.Description Valve clips for 50cc GY6 139QMB engines.These valve clips are used on a wide variety of scooters and ATV brands and models that have a Chinese built 50cc GY6 139QMB engine. WARNING California Residents: Proposition 65 Warning