BRAND NEW – NOT REBORED. YAMAHA QT 50 BIG BORE KIT to 60cc. POLISHED 60cc CYLINDER HEAD INCLUDED. Change the size of your engine, and feel the. Give your machine the new power and torque it really deserves, and have more fun with the power at your finger tips. 1x FREE SPARK PLUG. OUR KIT INCLUDES A POLISHED 60cc CYLINDER HEAD, DESIGNED TO WORK ON OUR KIT. OTHER SELLERS KITS WILL NEED TO BE MODIFIED. 1979 – 1987 QT 50. When you want to play, ZOOM ZOOMS the way!!! If order it is placed Mon-Fri before 2pm Est. Zoom Zoom Parts will gladly answer any questions or inquiries that you may have in a friendly response. We try our best to give customers the best business experience possible & hope we will do business again with you. Zoom Zoom Parts accepts.