Keefer gets a modified YZ250F with a second injector, Vortex ECU as well as an FMF muffler to go against a Honda CRF250R with a ported cylinder head, HC piston, Vortex ECU and Akrapovic muffler in order to see which one is better. Different mods may have different outcomes on the track so we dissect these mods and even call up the guy who built the bikes!
