Ported cylinder for Zenoah GZ25N14 (Geo) and GZ25N23 (GSR25, GSR Sport) engines. With professionally widened transfer, intake, and exhaust ports, this will make your Geo engine scream! Adds 2-3 mph and lots of power. Fits Geo-Sport, Geo-Bigfoot, Geo-X-ped, S25, X25, GSR25, and GSR Sport.