Do We Have a Winner? Simply put, yes. Each bike has its own strong points, and the weaknesses are so small in comparison that you can't lose. The Yamaha suffers with a restricted stock setting, but uncorked it comes into its own. Pulling off a balancing act like this in the off-road world is just what the WR is good at, and we couldn't fault it once we got it dialed. The Honda is the eldest in design and is seeking some tweaks to catapult it to the front of the class. As the CRF-X is ridable right off the showroom floor, none of our testers would mind owning one; a few would still pick it as their outright choice. Not a bad rating considering we still like the most dated, most easily picked-on bike this much. Kawasaki came out of the gate with a stellar machine that ups the performance bar above all, even the KTM. It is everything most riders could ever need in an off-road bike and, in the collective opinion of our staff and test riders, missing only one thing, but that one thing keeps the KLX-R from winning. It's the thing the KTM has: a license plate.The KTM EXC wins in our book because in a lot of places you need that little gem hanging off your rear fender to make riding possible. It makes more riding, yes, dirt-only riding, a reality. And in some states, it had better come from the dealer wearing that plate, because you can't convert a dirt bike to a streetbike. We'd have ranked the KTM 450 XC-W lower, but in this comparison and for the future of off-road bikes, the KTM 450 EXC wins.Making the Yamaha Run It is pretty easy to make the WR go from snore to score. Just buy the GYTR kit (GYT-5TJ93-69-01, $49.95) that includes the shorter throttle stop, a block-off kit for the Air Induction System (AIS) and a set of jets that bump the power by richening the jetting, then follow the included instructions. This is how we tested the bike in Costa Rica for its debut and in our first test. But in light of current standards and enforcements here in California, we also came up with the setting that we tested the bike in for this comparison. We used the shorter throttle stop, took out only the smallest stuffer from the muffler and removed the restrictor from the top of the airbox. We also disconnected the gray wire at the six-pin connector underneath the left sidepanel. We left the stock jetting in the bike and did not mess with the AIS, as it has no performance effect on the engine aside from causing the lean popping noises inside the exhaust. With this setting, we felt the bike was more ridable and smoother in the smaller throttle positions than the GYTR-jetted bike, and it got better fuel economy. Plus, it ran better at elevations above 7000 feet.Tuning the KTM The KTM is a dirt bike in a streetbike tutu. It has to have really tall gearing, a squeaky clean tailpipe and evaporative emissions (all dirt bikes will need to have this soon) to make the grade for the license plate. But we wanted that plate and to have our dirt bike back, which was easily had by dropping the skirt and pulling on a pair of pants. First, we tossed the stock 15/47 gearing and went to a 14/48 using the same chain. That was not enough, so we bumped it to a 14/50, still running the stock chain but flopping the axle blocks 180 degrees. Perfect for some, yet still gappy for others, this combo nevertheless totally eliminated the previously necessary clutch abuse on the trails and the resultant heat increase to an already hot-running lean engine. Making the throttle response come to life was almost as simple. Bumping the pilot jet from a 42 to a 48 and moving the clip position from the third position to the fifth got the hesitation minimized and the engine's lean-hot temperature better under wraps. Another thing that improved response was a Ready Racing Rapid Response throttle linkage (www.readyracing.com) that helped the response even more. Further gains were had by way of a Boyesen QuickShot2 (www.boyesen.com). One other trick: We relocated the horn away from the front of the radiator for better cooling. We put ours behind the headlight shell. We didn't touch the evaporative emissions lines or even remove the charcoal container tucked up in the airbox, though we could have easily done that. But one of the most important modifications you can do is to reroute the crankcase breather hose. Stock, it plugs into the back of the carb, and excess oil, especially on long downhills or in tip-overs, will flood into the carb and make the bike run poorly, or not at all. We took the hose, reversed it and routed it back to where the carb vent lines hang, and plugged the carb with an older KTM two-stroke coolant drain plug. On this bike, you should leave out the vent-line drain box's drain bolt, so the excess fuel can escape. And the pipe on the EXC is extra restricted to damp the sound beyond what the older-version KTM spark arrestors are capable of doing. By going to one of those older mufflers (or opening up the EXC's end-cap and removing the smallest snorkel), you can still pass the sound requirements easily. The bike does get louder when it is running at high rpm. At the same time, it definitely picks up some low-end grunt to get into the healthy midrange sooner.Honda CRF450X MSRP: $7399 Weight (ready to ride, no fuel): 276 lb
Seat height: 35.6 in.
Seat-to-footpeg distance: 19.9 in.
Ground clearance: 11.6 in.Yamaha WR450F MSRP: $7199 Weight (ready to ride, no fuel): 276 lb
Seat height: 35.1 in.
Seat-to-footpeg distance: 19.5 in.
Ground clearance: 10.6 in.KTM 450 EXC MSRP: $7998 Weight (ready to ride, no fuel): 275 lb
Seat height: 35.1 in.
Seat-to-footpeg distance: 19.0 in.
Ground clearance: 11.5 in.Kawasaki KLX450R MSRP: $7299 Weight (ready to ride, no fuel): 278 lb
Seat height: 35.4 in.
Seat-to-footpeg distance: 19.5 in.
Ground clearance: 10.8 in.