BBR Tuning Billet Aluminum High Compression 2-Stroke Motorized Bicycle Engine Racing Cylinder Head &ndash; Gas Bike Racing Cylinder Head Upgrade BOOSTS PERFORMANCE: The BBR Tuning Billet Aluminum High Compression Racing Cylinder head cap will boost your power from 20-30% from stock. It's hemispherical dome raises your engines compression and ensure evenly distributed combustion resulting in a large explosion and better utilization of fuel. INCREASED COOLING: This cylinder head features extra large heat sinks constructed of aircraft grade aluminum which dissipates heat more evenly and cools your cylinder up to 50% better than stock. Not only do you get better performance and cooling from this cylinder, it also makes your bike look great with its shiny billet aluminum and stylish machining. EASY INSTALLATION: Installation is a breeze: simple remove your stock head cap, replace your head gasket, install your new head, torque down your head cap, and you're ready to ride UNIVERSAL FIT: Designed to work with most 66cc and 80cc 2-Stroke motorized bicycle engines. *NOTE: This cylinder head requires 8mm head studs to fit properly. PACKAGE INCLUDES: 1x BBR Tuning Billet Aluminum High Compression 2-Stroke Motorized Bicycle Racing Cylinder Head