NCY 80cc Big Bore 50mm Cylinder Kit for 50cc 4-Stroke Kymco, SYM, 139QMB Scooters INCLUDES: Cylinder Block Piston Piston Rings Wrist Pin Circlips Gaskets COMPATIBILITY: BMS – Apache 50 4T, Heritage 50 4T Diamo – Classic 50 4T Gilera – Capri 50 4T, Ciclone 50 4T Lance – Charming 50 4T, GTR 50 4T Roketa – Bahama 50 4T, Maui 50 4T, Sicily 50 4T Tank – Urban 50 4T, Sporty 50 4T, Viaggio 50 4T Many Other 50cc 139QMB Based Engines **This will not work on the QJ models NCY GY6 50/QMB139 50mm bore Cast Iron Cylinder Kit w/o head. The perfect upgrade for most QMB139/GY6 50 scooters, this bolt-on 81cc kit will really give your scooter some go. It is recommended to get part number 1100-1239, 50mm big valve head as well, as most stock heads will not fit. In addition, we really recommend 1100-1250, NCY Performance Camshaft as an amazing complimentary item to this kit. It will allow the kit to perform to its maximum potential and go 50-55 MPH! Have a look at our Decompression Tube Assembly (1100-1282) which replaces your dipstick and allows excess crankcase pressure to be released. Good idea to install one of these alongside any cylinder kit upgrade. **NOTE: Not legal for use in California on pollution controlled vehicles. Check local laws before installing.** **