88bigStage 2.5: Carb Rejet and Tune. Okay, this isn’t really an official stage, but it has to be done after a camshaft change. It doesn’t matter whether your Twin Cam 88 is carburetedTB Race Head, 88cc B Bore Kit, & 20mm Carb Kit – XR70 & CRF70. complete 88cc bore kit, Race Head, and 20mm Performance carb kit. This