On the track and in the showroom, 450cc four-stroke motocrossers are the biggest and baddest roost-throwing holeshot magnets you can run. That distinction once belonged to 500cc two-strokes, but there are good reasons why those bikes are extinct, except for the exotic Service Honda, and better reasons why 450s are very much alive. While just a bit shy of the sheer power output of a gnarly 500cc two-stroke, a modern 450cc four-stroke produces nearly as much boost over a much-wider rpm range. Plus, any modern 450 is far less tiring and demanding to ride both physically and mentally. The real bonus is that 450s compete at the same level as top 250cc motocrossers; and as excellent as the current quarter-liter racers are, this is no small accomplishment. Perhaps most important, 450cc thumpers sell in significant numbers as no big-bore premix burner ever did, and that is a very concrete sign they appeal to modern riders. In fact, a large percentage of riders feel a 450 is actually an advantage on fast, outdoor-style tracks.No doubt you have looked at the pictures here, and you saw no yellow bike. You can't be any more disappointed than we are, but Suzuki arrived at the same conclusion we did in our initial test of the '05 Honda CRF450R: If you want to knock the Honda off the 450cc throne, you'll need to do your homework. Suzuki thought it had a bike that could compete head-to-head with the 2004 Honda; but this is 2005, and the company decided to delay releasing the RM-Z450 until it could ensure it would be a serious threat. We simply could not wait for it.However, with the new Honda chassis, the new KTM frame and fork tubes and a new fork and engine upgrades for the Yamaha, we had plenty of questions for a shootout to answer.We followed our usual format of running all of the bikes through three motos, wringing their necks for the radar gun and then testing for the best suspension and engine settings we could find. We relied on I-5MX and the new Competitive Edge tracks to develop our opinions. We began the group testing with Dunlop D756 rear tires and D742 fronts for Competitive Edge's softer terrain, then swapped the fronts for D739s before heading for I-5MX, where the surface is a little more clay-based.ForkAlthough the difference is modest in most cases, a 450 weighs as much as 15 pounds more than a 250cc two-stroke. Plus, a 450 makes a lot more power and torque than any type of 250cc machine. It is much harder to make a powerful motorcycle well suspended than it is to make a less-powerful one work in the same conditions. As a result, the suspension numbers from largely the same test crew are lower overall than they were in the 250cc two-stroke shootout (beginning on page 36). Whereas the Honda and Yamaha 250s ended up with the same rating, the CRF450R has a clear advantage. Again, our riders were tough graders, so this number represents a near-perfect score. Two riders awarded the CRF solid 10s; riders who didn't give it their highest rating dinged the Honda for a lack of initial plushness. In truth, there isn't much to complain about. The stock settings worked well. The Showa Twin Chamber is fairly plush and has a good, clean action and excellent bottoming feel. Riders attempted other settings, but most returned to stock.Yamaha switched to the new Air/Oil Separate System fork for '05 with great results, but the unit on the YZ450F didn't thrill our riders as it has on other models. Remember what we said about powerful bikes being hard to suspend? The Yamaha's motor isn't doing the suspension any favors with its hard-hitting delivery. While the new fork is plush, it didn't match the Honda's bottoming resistance or, to a lesser degree, plushness. Bottoming and plushness are also the KTM's weakness. Some riders rated its bottoming as better than the YZ-F's, while others felt it was a little more problematic. We tried setting it a bit stiffer than stock, but KTM recommended not to go less than 11 clicks out on the fork. The orange engineers claimed more-aggressive settings do not help bottoming but do add to the harsh feeling. Despite the ratings, none of these forks would keep us from racing these bikes stock.ShockShock performance is another aspect in which Honda earned a gold star. There was no waffling. Every rider saved his highest marks for the CRF, and it also garnered more perfect 10s. The overall rating is a composite of scores for plushness, action, braking bumps, bottoming and adjustability. In those subcategories only one rider awarded 10s to the YZ-F, but nearly every rider awarded 10s to the CRF. Honda made the 450's rear end as good as its fork, and they are a fine match. The suspension action is reasonably plush, well-controlled and trustworthy with few surprises and offers good bottoming resistance. A tendency to kick on braking bumps that we couldn't adjust out cost the YZ-F. The rear shock felt somewhat dead to some riders—as if we needed to speed up the rebound—and that only made the kick more pronounced. Riders tried going in both directions on rebound but in the end stayed with stock.Our crew did go stiffer on the KTM shock for low-speed compression, but just a bit. Since the KTM has no linkage, it can provide good bottoming resistance on jump landings but still bottom hard in G-outs. Adding high-speed compression helps; the 450 SX was the only bike on which much was done with high-speed compression. As with the Yamaha, the common thread here is bottoming. Bottoming was an issue, but some riders also found a lack of plushness.HandlingAs you can imagine, the bike with excellent suspension action, balanced front to rear, also earned high praise for handling, including a raft of 10s from Jimmy Lewis and nines from Kris Keefer (Keefer didn't award any 10s). You name it, and the Honda does it well. Riders who found any fault with the CRF mentioned stability as its single weakness.The Yamaha didn't get hit with major deductions; it simply was rated slightly lower in all areas of handling. Its stability was rated well by a unanimous decision, though. Usually, we see the suspension as being linked to a lower rating here, but we believe ergonomic issues and a hard-hitting engine may have hurt a basically fine-handling chassis.The KTM also was penalized with minor deductions across the board compared with the CRF; and in most cases it rated right with the YZ-F, with the exception of stability. Headshake was evident enough for every rider to mark the chassis down in stability. Again, it isn't as if any of these bikes have scary handling; it's just the CRF has "the whole package," which makes it tough to match.EngineHonda basically stuck its 2004 powerplant in the fourth-generation 2005 chassis, so you'd think there would be no performance changes; you'd be wrong. The '05 airbox is much more effective, and as a result, the CRF450R responds harder off the bottom than before. The power can be too strong for indiscriminate throttle jockeys. The higher the rider's skill level, the more he liked the CRF's engine. For one thing, it is the only five-speed, so there are slightly more options when it comes to selecting a gear for a certain track situation. You are more likely to find yourself between gears with the four-speed bikes. The Honda has the hit it needs for stadium-type obstacles, but mostly it has very smooth power delivery. Riders who had a complaint singled out a firm clutch pull.Between the other two engines, our team selected the KTM as their second favorite. The SX has more-noticeable vibes than the two Asian bikes, but it only bothered the picky or the sensitive. The hydraulic clutch works well, too. The power comes on even more smoothly than the Honda's and in a more linear fashion. More throttle equals more power. There is not much in the way of hit, either. Vet and novice riders regarded the orange engine as less tiring, but aggressive riders such as Lewis found they had to use first gear out of tight turns, and then they missed the first-to-second shift more than they were comfortable with. If you are looking for an engine that makes a lot of power without being intimidating, the KTM is your choice.We can't say the Yamaha is smooth, and it certainly can be intimidating. It is a little soft right off idle then hits hard and pulls hard through the middle. The power tapers off at high rpm, so it gives the impression it is short-lived. It isn't, but the bike isn't happy when you ride it like a YZ250F. We have issues with the power delivery for a number of reasons. It makes life tough for the suspension and puts the handling under a microscope. With less of a wallop from the engine and more-refined ergonomics, the YZ-F would be a lot closer to the CRF.ErgonomicsWith bikes as powerful as these 450s, an excellent bike/rider interface is critical, and Honda has the key to our hearts. The new chassis is slim but wide enough for comfort. It has a great seat, handlebar bend/brand and footpeg location. All of the bodywork is smooth with nothing to snag or irritate the rider. Honda pays attention to human engineering, and it shows. The KTM has an excellent handlebar with triple clamps that offer four handlebar positions and two fork-offset (18 or 20mm) positions. We left the clamps at the stock 20mm offset, but some riders preferred the bar clamp moved to the rear position on the top clamp. The standing riding position is roomy and great for tall riders and is adjustable enough to appease shorter pilots. The seated position is sufficiently roomy, but the seat doesn't win over many friends. The orange thumper is also the narrowest of the machines.The Yamaha won less friends than the KTM. We point to the bend of the new aluminum Renthal bar the blue boys chose for part of that conclusion. The bar is too low with more sweep than we like. Some riders also felt the pegs were high. Riders in the mold of Doug Dubach felt right at home; taller riders were always too far back on the bike. The seat made a few more friends than the KTM's, but not many. It wears less padding than its YZ250 sibling, but it does offer a flatter, more-supportive profile than the KTM's perch.BrakingAll of these bikes have good brakes. The KTM has the largest front disc and the most power, but some testers thought the front sudden and the rear brake pedal hard to find. When we averaged the numbers, though, the KTM enjoyed a slight edge. The CRF also has very powerful brakes, but they are extremely easy to modulate. Unexpected lockup is never a problem on the CRF.The Yamaha now has a Honda-style brake-hose routing, which helped the stopping power and front-brake feel. The YZ-F rated a little lower, but it really has great stoppers.Fit, Finish and Standard EquipmentAll of these bikes come well-equipped. The Honda has that work-of-art aluminum frame, light and strong wheels, a titanium/aluminum exhaust and (as with all of these bikes) an aluminum handlebar. It also has the best seat and great Dunlop meat. Some Hondas have had relatively short valve life, though Honda claims it is mainly due to riders who engage in sustained high-rpm running and/or bounce the bike off the rev-limiter a lot. Of course, letting the bike ingest any dirt will greatly compound the issue. Working on the engine is easy, but getting at the shock and carburetor is a challenge with the perimeter-style chassis. Adjusting the valves requires shims. The oil situation is a combination: Having separate oil systems for the engine and the transmission is nice in concept, but this does complicate oil changes a bit. Despite the real or perceived maintenance issues, the red rider rated highly.The KTM was up next with a powdercoated frame, a hydraulic clutch, quality rims, Bridgestone tires and an oversize handlebar. It also has those billet triple clamps with the adjustable handlebar position and offset. The seat and the choice of Bridgestones brought down the bike's score a little. We liked the M401/402 combo on the KTM 250 SX, but the M59/70 on the 450 wasn't as versatile. Also, the headpipes didn't seal perfectly, so we experienced some popping under deceleration. The KTM is easy to work on, with wheel spacers that are captive. The valves don't seem to be much of a problem; they adjust in one-third the time it takes for the Honda or Yamaha and with no need for shims. Oil changes are a snap, though two filters are required when it is time to change them. Cleaning all of the oil screens is additional work. Getting to the carburetor is painless, and the filter is the easiest to change and requires no tools. Naturally, there is no linkage to grease, either.The Yamaha has no perimeter frame, so it is fairly easy to access the shock and the carburetor. The wheels are strong, and the engine has a good reputation for reliability. As with the Honda, the Yamaha requires the valve cover be removed to check the valve clearance, and shims are necessary if any change is needed. The blue plastic is better for 2005 but will still white-mark when creased. Our 450's muffler had something loose or broken inside by the end of the test. The bike still ran fine, but it made a little clicking noise. Yamaha shods the YZ-F with hard-terrain Dunlop D739 tires that work very well until the terrain gets soft or muddy.Just One Choice?We can't deny this is a runaway win that will only convince more people we are on the Honda payroll. We'd be happy to show you the company name on our checks and refer you to the 125cc and 250cc two-stroke shootouts (Dec. '04 and elsewhere in this issue, respectively). We test the bikes, the riders fill out their sheets and we add up the numbers. We can back those up with our internecine struggle over who will get to ride the CRF450R for the year. It is the unanimous winner here for a reason. It does everything amazingly well while remaining comfortable and composed. The power will get your heart pumping, and it and the rest of the bike will keep a smile on your face. This bike really works as it should.That doesn't mean there aren't reasons to buy the others.The Yamaha will appeal to boost-heads who like a motor that barks out of turns. The bike feels a little lower and more suited to compact riders. Note how many desert/off-road types run the YZ-F. The big-boost motor loves tall gearing and responds well to tuning through pipes and flywheel weights. All of these bikes are high-performance, cutting-edge four-strokes that should not be confused with XRs, but the YZ-F has a good rep for engine longevity. It is also the lightest bike of this bunch.There are a lot of dedicated riders who feel a 450 is a little too much for the track. For those riders, the KTM offers an attractive option. Outside the pro ranks, the bike has a good record for longevity. It is also the easiest of these on which to do routine maintenance. The KTM isn't the lightest, but to some riders it feels light—or at least lighter than the YZ-F. The KTM is also a great choice for a tall rider.Choice is a great thing, and they say variety is the spice of life. These bikes have plenty of spice to add variety to your moto-life. We'd love to know where the RM-Z450 fits in, but it would have to be pretty darn wonderful to knock off the Honda!