Prima 58.5mm Aluminum Big Bore Cylinder Kit for 125cc Genuine BuddyINCLUDES: CylinderPistonRingsWrist PinCirclipsCylinder SpacerTop GasketsSPECIFICATIONS: Kit increases displacement to 161cc Increases torque and horsepower. Greater top speeds and faster acceleration. Best HP bolt-on, dollar for dollar! Fits the Buddy 125 engine only. Voids your factory warranty!Make your 125 scream! When you couple this cylinder kit with a Prima Buddy Exhaust, you gain 2.6 horsepower — a 36% increase in power! Add our big valve head and take it up to almost 45% more horsepower over stock! Keep going with a 26mm carb to take the power up even more.As for any performance upgrades on your bike, take it to your local scooter shop to have it tuned. Their experience in tuning will save you time and get the absolute best results possible from performance products.**NOTE: Not legal for use in California on pollution controlled vehicles. Check local laws before installing.****