Our Race Head has been updated for even more performance! It now has 25/22mm valves with better porting/flow. We also kept the combustion chamber the same size and changed the angle of the valves slightly. This will really wake up your stock engine and is comparable in power to the much larger Chinese 124cc engines!!!Lightweight aluminum cylinder with steel sleeve - Cast in mounts on cylinder for aftermarket skid plates - Oversized cooling fins on cylinder for efficient heat dissipation - 52mm high compression piston with rings, pin, & clips - Head gasket kit and clutch cover gasket. High performance race camshaft (for the Race Head only) - Race Head Larger valves (now 25/22mm) and better flow for increased performance. Also has bigger cooling fins. Includes all necessary parts and comes assembled! 06/08 - The exhaust valve has been upgraded to stainless steel (21-4N material). Includes: 20mm carb, intake, heatstop, gaskets, mounting hardware/wrench, long adjustable throttle cable, and a angled dual layer foam air filter. The item "HONDA CRF50 XR50 Z50r 88cc BIG BORE CYLINDER PISTON HEAD CAM CARB KIT TBPARTS" is in sale since Sunday, May 12, 2013. This item is in the category "eBay Motors\Parts & Accessories\Motorcycle Parts\Engines & Engine Parts\Big Bore & Top End Kits". The seller is "hondaproducts" and is located in Beaverton, Oregon. This item can be shipped to United States, Canada, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi arabia, United arab emirates, Qatar, Kuwait, Croatia, Malaysia, Brazil, Colombia, Antigua and barbuda, Aruba, Belize, Dominica, Grenada, Saint kitts and nevis, Saint lucia, Montserrat, Turks and caicos islands, Barbados, Bangladesh, Bermuda, Brunei darussalam, Bolivia, Ecuador, Egypt, French guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman islands, Liechtenstein, Sri lanka, Luxembourg, Monaco, Macao, Martinique, Maldives, Nicaragua, Oman, Peru, Pakistan, Paraguay, Reunion, Viet nam, Uruguay.