SSP-G 63mm Big Bore Cylinder Kit for 125cc – 150cc GY6 Scooters, ATVs, and Go Karts SPECIFICATIONS: Bore: 63mm Outer Sleeve Diameter: 64.9mm Displacement Increase to 180cc Overall Height (Cylinder): 90mm 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 **NOTE: YOU WILL HAVE TO BORE OUT YOUR ENGINE TO COMPLETE INSTALLATION** The Polaris RZR 170 engine is different than the GY6 150 engines used in scooters, ATVs, and go karts and does not need boring/machining. Bolt pattern is 80.5mm which is correct and head height also correct plus rocker arms in stock if needed to match up but should not be needed. **