Cylinder Kit NCY 88cc GY6 50cc 139QMB/QMA

88cc cylinder for you, although this is not a bolt-on item for most QMB 139 bikes. Most of the time, engine cases need to be cut. Order part number 1400-1001, Engine Boring Tool if there is no access to a machine shop. It is also recommended to get part number 1100-1239, along with the 50mm valve head, as some stock heads will not fit. Take a look at our decompression tube assembly which replaces your gauge and allows excess pressure to be released from the crankcase. Good idea to install one of these alongside a cylinder kit upgrade.

Then this 88cc big bore kit for you, although its not a bolt on item for most QMB 139 bikes. Most of the time, engine cases must be cut. Order part number 1400-1001, Engine Bore Tool if there is no access to a machine shop. Its also recommended to get part number 1100-1239, 50mm big valve head as well, as some stock heads will not fit. Have a look at our Decompression Tube Assembly which replaces your dipstick and allows excess crank case pressure to be released. Good idea to install one of these alongside any cylinder kit upgrade.