Universal Parts QMB139 Cylinder & Head Kit - 69mm Valves Options:39 Specifically engineered for the Segway

Specifically engineered for the Segway Ninebot Max series

ATVs and off-road karts

For use with 5/16" to 7/16" (8mm -12mm) outer diameter hose

The CST 10x2

while the aggressive shoulder lugs provide the necessary bite for confidence in dirt

Universal Parts QMB139 Cylinder & Head Kit - 69mm Valves Options:39 Specifically engineered for the Segway50cc QMB139 4 stroke Cylinder and Head Kit With 69mm Valves. Choose from 39mm, 47mm or 50mm bore in the Drop Down Box. 47mm Bore Upgrades your Scooter to 72cc! 50mm Bore Upgrades your Scooter to 81. 3cc! Kit includes complete cylinder head, cylinder, piston, rings, piston pin, cir clips, head gasket, and base gasket. *You may need to modify your engine case to accommodate the larger cylinder. Cylinder Bore: Choose from 39mm, 47mm or 50mm Cylinder