With the YZ250F's inception in 2001, the other manufacturers have had to step up their four-stroke programs or get left in the dust. And three years later we finally see some real competition for Yamaha's dominating four-banger. Knowing its rivals are closing in, big blue has continued to push the development of its little trendsetter. The '03 YZ250F was better than most expected, and for '04, the bike may appear the same, but don't let its unchanged look fool you. The new ride carries a few important refinements.The first thing Yamaha did was put it on a diet. Engineers were able to shed a full 2 pounds from the blue scoot. Paying attention to details, they swapped the oil-hose material from steel to aluminum and the header pipe from steel to titanium. How trick is that? That new titanium header is going to give exhaust manufacturers migraines trying to build a lighter one. Modifications were also made to the frame to help save weight: The gussets were decreased 0.2mm, and the overall shape was resculpted.Over the past few years the 250F has been notorious for its motor characteristics. The high-revving engine makes power at just about any part of the powerband. With a goal of more bark and less heft, the motor saw a few changes. The bottom of the cylinder sleeve has a bigger cutaway--increased from 15mm to 19.5--to reduce pumping loss, and its skirt's cutaway was increased to save more than 18 grams of weight and keep oil blow-by pressure to a minimum. Yamaha technicians rerouted the clutch cable from the right side to the left for a more-direct route to the newly designed actuating arm. The new path eased clutch pull a tad.The biggest and most-noticeable alteration to the thumper is the new 48mm Kayaba fork. The new fork is not far off from what our factory racing heroes were using just a few short years ago. It has a new treatment called "Kashima"--a coating that helps eliminate friction and gives the fork a better overall ride once the bike has seen some serious hours. The fork also received a hydraulic bottoming system. The new system helps avoid metal-to-metal harshness on hard landings. Finally, other neat and innovative changes are the all-new titanium footpegs, which save more than 130 grams compared with '03's steel pegs, and a new gripper seat cover.Moto TimeWe couldn't have tested the bike at a better place. We took it to a private facility in SoCal that featured both a supercross-style track and gnarly natural-terrain sections. A fast lap was about 4 minutes. All of our expectations were running high as the Yamaha 250F has never performed below our standards. We are happy to report that, once again, the 250F was more than what we had hoped for. The motor is even more responsive; it doesn't really matter what gear you are in, the motor always has power. What we liked best about the engine is you can short-shift it and have power or you can ride it on the rev-limiter. The motor still makes lots of overrev!The new fork is amazing. You now have some leeway to make mistakes, such as overjumping big jumps. Flat landings didn't seem to be as much of a problem as with '03's elastomer setup. The new hydraulic bottoming system cuts out most of the harshness in the fork, too. The stock compression setting is 12 clicks out. By day's end, we were at 9 clicks out. Under acceleration the shock does no wrong, but under braking the rear end seemed to be a bit soft and nervous at first, so we went in on low-speed compression from 12 to 8 clicks out. Then we adjusted high-speed compression from 11/4 turns in to 1, running sag at the recommended 100mm. All our finessing really helped the bike settle. The 250F handled well, but it took a bit of time to dial in the suspension to feel comfortable. The ergonomics are the same--a bit cramped for taller riders but nothing that can't be fixed easily. The new gripper seat works, with the look and feel of a factory race bike.Still Number One?Although the new 250F didn't enjoy a complete makeover, the truth is it didn't need one. With all the other manufacturers building 250 thumpers, the pressure is on, and Yamaha is responding. The '04 YZ250F is a fine-tuned version of last year's edition. It has all the essentials you could possibly need: It's fast, it handles well and, most important, it's easy to ride for any level of talent. Yet the new competition in the toddler class is going to make for a really interesting comparison; blue could very well be the color on top of the podium when it comes to the 125 shootout, but only time--and testing--will tell.