88bigTB Race Head, 88cc B Bore Kit, & 20mm Carb Kit – XR70 & CRF70. complete 88cc bore kit, Race Head, and 20mm Performance carb kit. ThisWith an optimal displacement of stock Twin Cam 88 ensuring the desn, the S&S 95 Black B Bore is patible with all models of Harley going as back as to the 1999 classics and fast forward to the 2006 innovative models.