Meet the X4R For 2009 the X4R features a powerful GPX 160x engine that has been reinforced to handle whatever you through at it. With refined suspension settings in the rear shock and changes like larger diameter shaft and forger shock body maximum strength and durability are obatined easily. The rear shock is protected by a mud guard to keep it working clean and leak free. The carburetor also received an upgrade with new settings making it easier to tune for any location. A new braking system featuring 220mm wave rotor up front and 190mm wave rotor in back to increase the stopping power of the dual piston caliper. There is also a brake pedal catch that helps prevent brake pedal damage if the bike slides out while riding. The hubs have been redesigned completely and are new light weight CNC with full aluminum hoop to help save on weight while being our strongest wheel ever.