trkimal 50mm cylinder kits for gy6 49cc 50cc 139qmb engine, upgrade gy6 100cc big bore rebuilt cylinder kits 4 stroke motor for moped scooter atv go kart. trkimal 1.trkimal brand in motorcycle parts<br> 2.upgrade 50mm 100cc cylinder kit for gy6 50cc 139qmb engine <br> 3.this parts fit most of chinese made scooters gokart and atvs.such as jonway,jmstar,roketa,sunl,tank,peace,taotao etc...<br><br> <b>package information</b><br> 1*cylinder<br> 1*piston<br> 1*piston ring<br> 1*piston pin<br> 2*piston pin clip<br> 2*valve oil seal<br> 1*cylinder head gaskets<br> 1*cylinder body gaskets<br> 1*tensioner gasket<br> 1*exhaust gasket<br> 2*intake studs<br> 2*exhaust studs<br> 2*exhaust nut<br>