NCY 61mm Big Bore Cylinder Kit (Aluminum) for 125cc – 150cc GY6 Scooters, ATVs, and Go Karts INCLUDES: Cylinder Piston Piston Rings Circlips Wrist Pin Gaskets COMPATIBILITY: Amigo – 150cc Scooters, ATVs Apollo – 150cc Scooters, ATVs, Go Karts Baotian – 150cc Scooters Baron – 150cc Scooters Bintelli – 150cc Scooters BMS – 150cc Scooters, ATVs, Go Karts Coolster – 150cc Scooters, ATVs, Go Karts Diamo – 150cc Scooters, ATVs Flyscooter – 150cc Scooters Gorilla Motor Works – 150cc Scooters Ice Bear – 150cc Scooters, ATVs, Go Karts Italica – 150cc Scooters JCL – 150cc Scooters, ATVs, Go Karts Jonway – 150cc Scooters Kandi – 150cc Scooters, ATVs, Go Karts Kinroad – 150cc Scooters, ATVs, Go Karts KMD – 150cc Scooters, ATVs, Go Karts Lance – 150cc Scooters, ATVs, Go Karts Leike – 150cc Scooters Linhai – 150cc Scooters Longbo – 150cc Scooters Motobravo – 150cc Scooters, ATVs, Go Karts Motofino – 150cc Scooters Motorino – 150cc Scooters NST – 150cc Scooters, ATVs, Go Karts Peace – 150cc Scooters Puma Cycles – 150cc Scooters Redstreak – 150cc Scooters Roketa – 150cc Scooters, ATVs, Go Karts Scootstar – 150cc Scooters Schwinn – 150cc Scooters SSR – 150cc Scooters, ATVs, Go Karts SUNL – 150cc Scooters, ATVs, Go Karts Supermach – 150cc Scooters, ATVs Tank Sports – 150cc Scooters, ATVs TaoTao – 150cc Scooters, ATVs, Go Karts Trailmaster – 150cc Scooters Veloz – 150cc Scooters Verucci – 150cc Scooters, ATVs, Go Karts Vitacci – 150cc Scooters, ATVs, Go Karts Viva – 150cc Scooters, ATVs, Go Karts Wolf – 150cc Scooters Xingyue – 150cc Scooters ZNEN – 150cc Scooters NCY GY6 150 61mm Cylinder Kit w/o head 62.5mm outer sleeve diameter. Give your GY6 based scooter some serious power with this bolt on 171.3cc kit for most GY6 125/150cc engines. As far as we know, this is the only 61mm cylinder kit for the GY6 engine that exists in the US. With most 61mm cylinder kits, you have to cut the engine cases in some way to make it fit. Not so with this kit. It also has a light weight cut down piston to increase performance even more. It??s highly recommended to jet this kit significantly rich because of its high performance capability. In addition, it??s recommended to get our 61mm big valve head as well. Some stock heads will not fit. **NOTE: YOU WILL HAVE TO BORE OUT YOUR ENGINE TO COMPLETE INSTALLATION** **NOTE: Not legal for use in California on pollution controlled vehicles. Check local laws before installing.** **