ROCKER ARMS CAMSHAFT HOLDER 64MM VALVES GY6 49CC 50CC 139QMB SCOOTER ATV RA04 Scooter Rocker Arm Assembly For GY6 49cc 50cc QMB139 Condition: Brand New Note: Some engines use 64mm long valves and some use 69mm valves, you will need to find out the length of your valves before the purchase. 50mm across all mounting holes, please note this rocker arms assembly only works for 64mm valves, will NOT work for 69mm head