aren’t telling tales out of school, but the most important attribute of a 250cc four-stroke is how much power it makes. Using that criteria, the 2013 YZ250F falls drastically short. ( 2) Electronic fuel injection. The YZ250F is the only big-bike four-stroke that relies on a carburetor. In truth, we don’t think that the Keihin carb is what is holding the YZ250F back, since many of the current fuel- injected bikes actually had better powerbands when they were carbureted. However, it’s hard to deny the simplicity of electronic fuel injection. The MXA wrecking crew may be masters at working on the 39mm Keihin FCR carb, but most people don’t want to swap jets based on atmospheric conditions. Public opinion dictates the need for Yamaha to slap EFI on the YZ250F. We’re going to go out on a limb and say that every adult displacement four-stroke will be EFI-equipped in 2014, because the YZ250F is either going to join the party or end up as a wallflower. ( 3) Exhaust. We’re proponents of decreased sound levels, but Yamaha went to great lengths to choke down the YZ250F. How so? The muffler core is extremely small and doesn’t allow the engine to perform at its best. Last year we drop-kicked the stock exhaust system for an FMF Factory 4.1 RCT system ( www.fmfracing.com). It noticeably improved midrange and top-end power (something that the YZ250F desperately needs). Q: OKAY, IF NOTHING IS NEW IN 2013, WHAT WAS NEW IN 2012? A: Yamaha made several quality changes to the 2012 YZ250F. The Yamaha engineers focused on massaging every area of the bike. Most of these updates positively affected the YZ250F (e.g., 2mm-larger carburetor bore, lighter piston, 50-tooth rear sprocket, new frame and stiffer fork springs). There were, however, a few flies in the ointment (e.g., 8mm-smaller muffler core, black rims and a horsepower deficit). Yamaha took several steps in the right direction a year ago, but that doesn’t really compensate for taking no steps in any direction in 2013. Q: HOW DOES THE 2013 YAMAHA YZ250F COMPARE TO LAST YEAR’S MODEL ON THE DYNO? A: Yawn. Last year’s dyno chart is this year’s dyno chart and vice versa. Maximum horsepower on our 2013 YZ250F was 37. 13 ponies at 11,500 rpm. Maximum torque was 19. 55 foot-pounds. How does the YZ250F engine compare to its competition? Unfavorably—and that is the nice way to say it. The 2013 Kawasaki KX250F makes four more horse- power ( 41. 16 horsepower), while the KTM 250SXF wallops
2013 Yamaha YZ250F: It doesn’t take
Sherlock Holmes to find that the 2013
YZ250F bears a striking resemblance to its
predecessor. The only updates to the new
model are visual, with graphics, black
handlebars and a white rear fender.