2012 YAMAHA YZ250F, b NEW FOR 2012 WITH MORE POWER and BETTER HANDLING /B P The new 2012 YZ250F features a new Bilateral Beam frame, beefy new front suspension components, revised rear shock internals, and more rigidity in the swing arm axle block area. Engine refinements include a larger 39 mm carburetor, optimized CDI, and lighter piston with a lighter piston pin for more power as well as exceptional throttle response in the mid-to-high speed range.