The BPF is one of the great contributing factors to the Ninja ZX-6R’s great composure under braking. Compared to a cartridge-type fork of the same size, the BPF features a main piston almost twice the size (φ37 mm vs φ20 mm on ZX600P); oil inside the BPF acts on a surface area almost 4 times the size. Compression and rebound damping adjustment are located at the top of each fork tube. Preload adjustment is at the bottom.