How can two off-road bikes look so alike and yet be so different? That's the question that came to mind while testing both the 250cc and 450cc versions of the '04 KTM enduro four-strokes. We were in Ontario, Canada, filming the first episode of "Dirt Rider Adventures" for the Outdoor Life Network, and we had the two brand-new, zero-miles E/XCs to use in the show. The 450 was designated for Editor-in-Chief Ken Faught, and the 250 was for show host Molly Culver. We were able to ride both bikes and explore some awesome trails and terrain in our first test of these new mounts.The 250 and 450 share virtually identical chassis specifications and many of the same basic engine castings. In fact, the displacement stickers on the sides of the bike are the only quick way to determine which is which! But the reality is that these two offerings are as different in their performance characteristics as they are similar in appearance.Faught, Adventure Travel Editor Lee Klancher, actress/host Culver (a former tough-girl star from the "V.I.P." series with Pamela Anderson) and eight-time National Enduro Champion Dick Burleson, along with domestiques Jeff San George and Mark Frederick, all met in Elliot Lake, Ontario, for the first episode of our new television show. The show's focus is exploring real off-road adventures that are accessible to everyone, not just elite riders, and for the debut our base camp was the beautiful Laurentian Lodge.The site was originally a fishing and hunting lodge on Flack Lake about three hours from Sault Ste. Marie, Michigan--basically in the middle of nowhere. In fact, it's so far out there that Culver flew in on an ancient Beaver floatplane with her KTM strapped onto a pontoon. The lodge--which offers camping, new rooms on the beach, a grand banquet room and a beautiful restaurant built from indigenous logs--was home for three days of extensive riding and filming and some lake trout fishing, with which we had some success. Virtually unlimited snowmobile and ATV trails surround the lodge, providing an excellent location for the outdoor powersport-oriented enthusiast. While most of the trails are built and used by quads, the rocky, hilly and woody terrain offers scenic and challenging trails for all off-roaders.What we confirmed immediately was that the 450 E/XC is a serious race bike right out of the crate. It comes complete with lights, a USFS-approved spark arrestor, a 96-decibel muffler, an electronic speedometer/odometer/clock and a fuel tank large enough for some serious exploring, not to mention the powerful yet controllable engine. Unchanged from 2003 except for the clutch, the engine is a powerhouse, with strong bottom power, a big burst in the middle and a top-end approaching 90 mph with stock gearing. The new exhaust system helps the engine to provide a stronger torque curve than the '03 model. The wide-ratio gearbox has a low first gear for rock crawling which, when combined with the perfected hydraulic clutch, lets the rider explore any and all terrain.In contrast, the 250cc version has to be revved to make any real power. The carburetion was a little lean out of the crate, but after we richened the needle one clip position, the engine carbureted perfectly. No one would call the bottom power strong; nonetheless, the motor will pull along smoothly and then rev out on top with good power. Where the 450 barks--and wheelies--the 250 accelerates in a friendly way, perfect for less skilled or less aggressive riders. The 250 gearbox is also a hybrid, exclusive to this engine, and has very close spacing, helping to keep the engine working at its best. The downside of the gearbox is a limited top speed of slightly more than 60 mph, but that's enough for the intended customer. In a further effort to help the motor's performance, the 250 comes with a non-O-ring chain, which has less drag. While an O-ring is de rigueur for off-road racing, KTM has specified a high-quality chain that needed only one adjustment during the three days.Because we were able to switch back and forth between the bikes, we discovered just how large an effect engine characteristics have on the handling of the machine. Even though the frame, suspension and engine placement is the same, the 250 has a much lighter overall feel. It's more flickable on tight trails and stops and turns with less effort. On the other side of the coin, though, the 450's front end actually feels a little lighter due to much more available torque from the bigger motor.What was surprising was that even though the 250 doesn't have a big hit, after getting used to almost constantly revving the engine, we could actually go pretty fast on the bike. Riding it like a 125 is the key. Fortunately, the hydraulic clutch makes this style of riding manageable, with easy pull and consistent engagement. And if you don't want to go at a race pace, the 250 will move along in a very comfortable way, since the state-of-the-art, race-ready chassis can handle virtually any terrain with ease. While the 250 isn't for the serious racer, it offers a major step up from the 250cc four-stroke trailbikes in both chassis performance and overall quality of components. The combination of the new exhaust and a compression ratio that has been upped to 12:1 has improved the overall performance of the motor from the '03 model. The electric start is the icing on the cake, making the package the best choice for a less experienced rider.For pure adrenaline-packed performance in an off-road setup, the 450 E/XC is the way to go. The stiffer frame helps keep the bike in line, and the new suspension settings and straight-rate shock spring hold the bike up in the travel better than previous models, noticeably reducing squat on acceleration. The only drawback is the high seat height, caused by the SX style seat. While it looks as if there are 4 inches of foam padding, the seat base is undercut to increase the volume of the airbox, reducing the effective foam to less than 2 inches. Tall riders such as Mike Lafferty love the new seat, but short guys such as Burleson struggle to maintain balance in dicey situations. Since the power of the motor is so strong, it would seem that a flatter seat base wouldn't noticeably reduce the power yet would vastly improve the seat comfort and height.So while these machines basically look the same, the 250 offers high-end chassis performance with a comfortable and manageable powerplant, perfect for the less experienced or less aggressive rider. The 450 is much better able to satisfy the racer in us. With the improved chassis to handle the strong motor, it can be ridden comfortably at speeds anywhere between neophyte rock crawling and National enduro champion check zeroing. And with electric start just a thumb push away, overall fatigue and time delay from starting is eliminated. It's just going to be hard to beat this combination of solid chassis performance and 450cc of right-now power that is assembled with all the necessary off-road accessories. If you have that need for real speed off-road, then the choice is clear--go orange, and go big!