The 450R was a good bike, but this, this is GREAT!

Mods include:
Works Connection Radiator braces
Works Connection skid plate
Works Connection guards on rear disc, rear oil
Fastway chain guide
Rear running light converted to brake light
DR D's hour meter
Panoram Cycle computer
Fastway front disc protector
Wanted:
GPR Steering damper with built in adjuster on bar

With numerous magazine accolades and roaring approval from riders coast-to-coast, the electric-start CRF450X is the favorite big-bore off-road machine for racers and weekend warriors alike.

Features & Benefits

New for 2006

• Race Team-inspired graphics.

Unique features

• Electric-start system for easy starting in all conditions.
• California model meets California Air Resources Board (CARB) emission standards.
• Fuel-tank capacity is 2.27 gallons.
• Resettable, easy-to-read three-digit odometer.
• USDA-qualified muffler/spark arrester.
• Powerful 35-watt halogen headlight features new lens type for wide range of illumination.
• Integrated LED taillight in rear fender.
• Convenient sidestand integrated into left footpeg bracket can be easily removed for competition events.
• Easy-access air filter.
• Wide-ratio five-speed transmission.
• Suspension and chassis tuned for competitive off-road riding needs.
• 18-inch rear wheel for greater flat-tire protection.
• T-ring-sealed chain is narrower, stronger and lighter compared to conventional O-ring chains.
• Skidplate and engine guards feature a unique three-piece design.

Engine/Drivetrain

• Powerful four-stroke 449cc liquid-cooled four-valve Unicam engine is designed to produce power across a wide rpm band for off-road riding.
• Electric starter drives the clutch side of the crankshaft to provide superior lubrication of starter gears, and produce a narrow engine with a short, strong crankshaft.
• Lightweight, compact, internal auto decompressor system provides superb cold-starting and hot-starting operation.
• Compact, lightweight engine assembly weighs only 71 pounds.
• Unicam valve train provides the light weight of a compact single-cam design and the optimum combustion chamber shape for maximum power at all engine rpm.
• Unicam valve train features a carburized single camshaft that directly actuates two 35mm titanium intake valves. The camshaft exhaust lobe actuates two 30mm steel exhaust valves via a forked, low-friction, roller rocker-arm.
• Lightweight titanium intake valves permit use of smaller valve springs, reducing overall engine height.
• Crankshaft is made of high-strength, low-carbon steel with carburized main journals for maximum durability at sustained high-rpm operation.
• Clutch cover and cylinder head cover are made of magnesium to reduce engine weight.
• Forged 12.0:1 compression slipper piston is lighter than a conventional design, revving quickly while maintaining excellent cylinder sealing and high-rpm power.
• Double-carburized connecting rod utilizes an updated big-end needle bearing and thrust washers for maximum high-rpm performance and durability.
• Nikasil cylinder lining is lightweight and provides cooler and quieter operation for extended engine life.
• Press-fitted aluminum spark plug pipe fits between forked exhaust rocker arms, further contributing to compact cylinder head design.
• 40mm Keihin FCR-type carburetor features four rollers on the flat slide, resulting in very light throttle effort, smooth operation, crisp throttle response and excellent rideability.
• Carburetor features a throttle position sensor (TPS) that helps maintain linear throttle response throughout the rpm range.
• Twin-sump lubrication system separates the oil supply for the crankshaft, piston and valve train from the clutch and transmission. This ensures a cool supply of oil to the clutch, eliminates clutch and transmission material contamination of the engine oil, reduces the amount of circulating oil and permits the use of a smaller oil pump.
• Vertically split crankcases feature a built-in oil pump, reducing weight compared to a conventional design.
• Exhaust system uses a lightweight stainless steel exhaust header and muffler equipped with spark arrester.
• Dual radiators feature a refined core area for improved heat dissipation compared to conventional dual-radiator design. Coolant recovery tank is located in front of the engine between the frame down-tubes for improved center of gravity. Coolant tank is protected by plastic skid plate.
• Gear-driven balancer reduces vibration and drives the water pump. Eight clutch plates provide the surface area necessary to handle the engine's massive torque, while carefully matched clutch springs provide a light feel at the lever.
• T-ring-sealed chain is approximately 1.6mm narrower, and stronger compared to conventional chains.
• Durable and versatile five-speed wide-ratio transmission.

Chassis/Suspension

• Fourth-generation twin-spar aluminum frame. Forged aluminum steering head and tapered downtube section are designed to optimize frame rigidity. In addition, tall swingarm pivot plates and narrow frame spars create a narrow overall frame cross-section for superb rider comfort and maneuverability.
• Semi-double-cradle frame design features a single, large-diameter tapered downtube. Two rugged box-section rails attach to the base of the downtube and support the engine. A forged aluminum steering head provides a compact and extremely durable mount for the frame spars and engine downtube.
• The aluminum frame design is matched to rider ergonomics to maximize handling and control operation.
• Swingarm features a dual-axis, double-taper design with a large cast aluminum cross-member offering high strength and light weight.
• 18-inch rear wheel features same lightweight rear hub and HRC works-type lightweight aluminum spoke nipples as used on CRF(R)450R.
• Front wheel features large-diameter front axle and wide wheel-bearing span for excellent rigidity.
• Rear-axle diameter of 25mm and large-diameter bearings provide optimum rigidity to withstand torturous off-road conditions.
• Lightweight, 47mm inverted Showa twin-chamber cartridge fork with aluminum dampers is derived from the CRF450R and features settings unique to the CRF450X. The fork offers 12.4 inches of travel, 16-position rebound and16-position compression damping adjustability. The inner surface of the front fork outer-tubes receives the same honing treatment as works bikes for low-friction operation.
• Pro-Link(R) single-shock rear suspension system features a fully adjustable Showa rear damper and 12.4 inches of wheel travel, separate low-speed (13 positions) and high-speed (3.5 turns) compression damping adjusters, and 17-position rebound damping.
• Rear shock damper piston diameter is 50mm for consistent performance under demanding riding conditions.
• Compact twin-piston front brake caliper, anodized aluminum brake pistons and lightweight front brake disc minimize unsprung weight for improved turning and handling.
• HRC works-type rear brake system integrates the rear master cylinder and fluid reservoir, eliminating the need for a remote master cylinder reservoir and hose assembly.
• 240mm front and rear brake discs.

Additional Features

• All plastic body components (radiator shroud, side covers, rear fender, seat base,fuel tank, front fender, and front headlight) are designed for slimmer, more aggressive styling and light weight.
• Airbox features easy access to reusable foam air filter.
  - Rider ergonomics are optimized by adapting the handlebar, seat and footpeg height to place the rider's legs at the narrowest cross-section of the frame for improved comfort and handling feel.
• Seat cushion uses foam construction that follows the shape of the fuel tank, providing a smooth transition to increase rider mobility and comfort.
• "Non-slip" seat cover for increased rider control.
• Rear-brake pedal and shift lever are made of lightweight aluminum and are designed to complement the riding position. Brake pedal features optimized ratio to match integrated rear-brake master cylinder design.
• Wide, cleated stainless steel footpegs are self-cleaning, resist corrosion, provide excellent grip and fold for extra ground clearance.
• Aluminum Renthal handlebar (971 bend) is rubber-mounted to reduce rider fatigue and improve comfort.
• CR(R) handlebar holders provide three different mounting positions: standard CRF450X holder (CRF450R/CR125R/CRF250R-type) provides +/- 3mm fore or aft position to match rider preference, and optional holder (CR250R-type) provides neutral position.
• Works-type handlebar grips add to rider comfort.
• Adjustable front brake lever.
• Hot-start lever conveniently located on clutch perch.
• Quick-adjust clutch perch.
• Chain guide material offers durable wear resistance, and service life is five times greater than conventional materials.
• Front disc brake cover helps protect rotor and caliper from damage.
  Removable rear subframe allows easy maintenance.
• Washable, two-stage foam air filter for optimal engine protection and easy maintenance.
• Comfortable, durable controls and high-quality fasteners.
• Stainless steel clutch cable for long life.
• Honda Racing-inspired colors and graphics.
• Ownership includes one-year complimentary membership for an individual in the Honda Rider's Club of America(TM) (HRCA(R)). Benefits include: discounts, travel benefits, roadside assistance, one year of Honda Red Rider(TM) magazine, access to HRCA Clubhouse Web site (www.hrca.honda.com) and access online to Honda Common Service Manual. For HRCA details, call 1-800-847-HRCA. For dealers only, please call (310) 783-3958.

2006 Honda CRF450X- Specifications

Common sense seems to dictate that when something works, you stick with it. Following that thread of logic, if you already build the best motocross bike in the world, you could then create the world's best off-road machine by sticking with that base bike and adding a few tidbits. Simply install a bigger generator to power a lighting system and add flywheel weight, slip in a set of wider gearbox ratios, and call it a day.

While some manufacturers take this path, Honda does not. At Honda, commonplace solutions never override the quest for excellence. And because off-road competition differs drastically from closed-course motocross racing in myriad ways, machines for each purpose really should be developed autonomously to satisfy their decidedly differing parameters. All of which explains why virtually every single component on Honda's stellar CRF450R motocrosser has been changed to meet the unique demands placed on the CRF450X off-road machine.

When Honda engineers designed the four-stroke CRF450R motocrosser, they built it with the single-minded purpose of creating the best race machine in the world. By most measures - racing results, magazine comparisons, etc. - they succeeded. The world of off-road competition, however, demands an entirely different skills set, if you will. Sporting an ability to devour triple jumps, blast big bermshots and handle everything in between, a motocross bike would seemingly be ready to tackle anything the dirt has to offer. But once you've experienced the snaking pursuit of a GNCC course, the full-throttle-blasts of WFO speed in wide-open desert races and the mud-slinging slogging through endless stands of trees common to enduro events, you understand that the far-ranging requirements for off-road work have little to do with what a motocross or Supercross track demands.

Of course, to transform a championship-caliber motocross machine into a world-class off-road bike, Honda's engineers began at an enviable starting point: the CRF450R. Although both 450s share the same essential engine architecture and basic chassis design, virtually every piece on the CRF-X has been redesigned in the process, with the expressed intent of reaching the apex of performance in off-road function.

Same face, all new parts

Far from a Honda 450 motocrosser with lights, the CRF450X's list of altered parts runs from large to small, with plenty of changes in between. Just a highlight of the major changes includes:

- New cylinder head and valves to improve intake velocity and engine response
- New cam for a wider torque spread and increased low-end and midrange punch
- Wide-ratio gearbox for more versatility in varying terrain
- Added flywheel weight for more tractable power delivery
- New exhaust system complete with spark arrestor for added torque
- Larger fuel tank for greater range
- Electric starter, battery and high-output ACG - plus a backup kickstarter
- Completely new frame carefully tuned for off-road use, not motocross tracks
- More compliant suspension components for a plush ride over rocks and roots
- Revised linkage ratios for the Pro-Link rear suspension system
- An 18-inch rear wheel and tire for added flat-tire resistance
- A new lightweight slim-line headlight, plus a trick LED taillight
- Standard-issue sidestand with a clever mounting system integrated into the left footpeg bracket
- Both CARB and EPA certification in stock trim

Considering this is just the brief list, the CRF450X obviously incorporates substantial changes indeed. And while this list represents some of the nuts-and-bolts changes, the CRF450X's development involves an equally complex human tale.

Hands-on experience counts

When Honda's product development team set out to transform the 450R into the 450X with an entirely new off-road personality, the pursuit was neither academic nor theoretical. The process involved countless hours of hands-on testing by Honda's product development specialists. Feedback traveled back and forth from tester to engine and chassis engineers, resulting in new hardware that required more testing, more feedback. And that circle of development/testing goes on and on and on.

As one engineer explained, "For a while there, the testing procedure for the CRF450X seemed like a never-ending process. A number of times in a month, for a period of about 10 months straight, we tested new variations of chassis and engine alterations. Sometimes we tested in America, sometimes in Japan. And we had to test the bike in all kinds of terrain, all across the United States: sand, desert, woods, rocks, mud, tight trails - the whole works."

And even though this group had earlier worked on crafting the CRF250X off-road bike starting with the CRF250R motocross machine, the CRF450X proved to be a completely different animal at times. "In some ways it was easy to engineer the CRF450X, because the 450R is such a wonderful motocross bike," the engineer said. "In addition, we had a lot of solid data we gathered with our hands-on experience working with the CRF250X. However, many times the changes did not translate directly; we had to find new answers. But our previous experience had at least given us a process we could pursue during development of the 450X."

Key goals for the engine focused on maintaining the CRF450's class-leading performance, while retuning the engine to shift the power peak downward a bit in the powerband - all the better to focus on midrange punch, that most usable of real-world assets when riding off-road. Additional flywheel effect and a new wide-ratio five-speed gearbox increase the versatility of the 450X, and the addition of an electric starter commanded high priority. But complex as this may sound, chassis development proved even tougher yet.

Handling the bigger picture

Given the nature and scope of off-road riding, the very core of the CRF450X's aluminum frame and suspension had to offer more bump absorption and a plusher action than is common to motocross machines. Typically, off-road riders must deal with nonstop small-to-medium-sized irregularities in the trail, such as rocks, roots, bumps, dips and more, obstacles that jump up at weird angles and at the most inconvenient times and places. A bike designed for motocross will transmit too much bump impact under such conditions, often resulting in front wheel deflection that can wear out the rider in short order. A more supple and compliant package - suspension components and frame - is the order of the day for top off-road performance, and that's exactly what the CRF450X delivers. But a deeply complex picture lies beneath that simple explanation.

" We wanted to keep a lot of the CRF450R flavor, if you will," said one product development team member. "The 450R is a great bike, but the chassis is too rigid for optimum off-road use. So we made changes to the frame and suspension that would make the entire CRF450X package more compliant feeling, but we still had to maintain its high-speed stability, tracking ability and steering precision. It's all a delicate balance, but we found that sweet spot."

As explained in detail in the CRF450R technology section, virtually every single piece that makes up the 450X frame was re-engineered. In addition, the entire suspension system, including the fork, shock and linkage ratio on the Pro-Link rear end, has been recalibrated to produce a more compliant, plush ride specifically suited to the rigors of off-road use. All in all, the X-model chassis transformation required a monumental effort - but one that yields monumental results.

An engine brand-new through and through

Even though the CRF's 449cc engine offers a wealth of power, Honda once again re-engineered the entire powerplant - not to make more power, but to create a spread of power better suited to off-road use, and to also add conveniences and durability for use over repeated long-distance events. The X-version of the 450 engine retains the basic architecture of Honda's innovative Unicam four-valve powerplant. The overall engine layout remains unchanged, but the 450X incorporates intake and exhaust valves 1.0mm smaller in diameter to increase intake charge velocity and thereby improve throttle response. Many familiar key Honda innovations remain, such as the high-tech forged 96mm slipper-type piston with a compression ratio of 12.0:1, Nikasil(R) cylinder liner, and 40mm flat-slide carburetor.

However, the addition of a much-desired electric starter dictated the creation of all-new engine cases, and the cylinder, head and camshaft are new pieces as well, even though they mirror CRF-R design. As would be expected, the CRF450X features a wide-ratio five-speed gearbox that's tougher than ever for added durability, plus lower final-drive gearing than the motocross version of the 450. To give the 450X a more tractable power delivery, Honda's engineers also added more mass to the AC generator and flywheel for improved low-speed power. In addition, there's a new exhaust system tuned specifically for off-road use via a longer head pipe, and it's capped off by a USDA-qualified muffler/spark arrestor.

Built to take on the world

To better equip the 450X to fulfill its varied off-road missions, fuel tank capacity now stretches to 2.27 gallons, enough for a 50-mile loop and then some. Compared to the R model, the seat is wider and sports rounder edges, and it's built with a different foam density designed for long-range comfort. Even the aluminum Renthal handlebar contributes to rider comfort by passing less vibration on to the rider. Another nice touch for off-road applications is the addition of an engine guard to provide more protection for the engine cases. A powerful 35-watt halogen headlight pumps out plenty of illumination after dark, and a trick but eminently practical LED taillight has been integrated into the rear fender. As would be expected, an easy-to-read, resettable three-digit competition-style odometer rounds out the package. Add it all up, and the sum of these parts leaves nothing to be desired, whether you're plonking down a trail for fun or flogging your way to the last checkpoint to take the overall win.

Riding enthusiasts who are serious about obtaining the ultimate off-road machine often put out the call for a motocrosser with lights. That's to be expected, since these high-flying MX machines normally represent the most advanced technology you can buy. However, Honda has taken the cutting-edge technology of its beloved 450R four-stroke motocrosser, and infused specific off-road technology through and through to create an all-new off-road machine with performance unmatched by anything in its class: the 2005 CRF450X.

Torrance, Calif. 01/19/2005 -- Imagine if you will, a family with twin brothers. These brothers, however, are fraternal twins, not identical twins. Although bonded to each other with inseparable genetic ties, they are still and all quite unique from one another. Let's also suppose these brothers are both excellent athletes, uniquely gifted. However, one eventually chooses to pursue the sport of football, while the other takes up basketball. And while these two sports are entirely different, each of these two brothers excels in his own chosen venue, and the twins quickly emerge as superstars.

This analogy perfectly describes the kind of relationship shared between the Honda CRF450R motocrosser and the brand-new CRF450X off-road warrior. Both have been spawned by the creative minds at Honda, and both can be considered twins with regard to the mechanical genomes that comprise the powerplant and chassis wielded by both machines.

However, even though the CRF450X faithfully follows the R-model's basic engine and chassis architecture, virtually every piece has been re-engineered to fulfill a completely different mission: To be the best open-class off-road machine in the world.

A winner by design

Like the CRF450R, the roots of the 450X engine spring from a high-tech, liquid-cooled four-stroke layout with a bore and stroke of 96mm x 62.1mm, to yield a displacement of 449cc. But the design element that sets both bikes apart from any other four-stroke is Honda's innovative Unicam(TM) single-overhead-camshaft configuration with a separate cam holder that contributes to a notably compact design.

This design incorporates a carburized single camshaft that directly actuates two titanium intake valves. The camshaft's single exhaust lobe acutuates two steel exhaust valves via an innovative forked rocker arm that incorporates a small roller bearing. This roller bearing significantly reduces friction, and therefore wear, so the cam lobe can be narrower and lighter than traditional counterparts. Valve adjustment is accomplished with shims; the intake valves use a direct shim-under-bucket system, while the two exhausts incorporate shims between the rocker arms and keepers on the valve stems.

Because this big-bore engine already churns out power to spare, Honda engineers enjoyed the luxury of reshaping the copious power curve so the CRF450X would deliver what off-road riders prize most: a responsive, torque-laden engine that puts easily accessible power to the ground under all conditions. Therefore, the X-model incorporates a new camshaft that enhances the torque spread compared to the 450R, with new timing specs as follows, reflecting less duration and overlap:

The CRF450X also sports a brand-new cylinder head fitted with ultra-lightweight titanium intake valves with faces measuring 1.0mm smaller in diameter (35mm vs. 36mm). The steel exhaust valves are likewise a pinch smaller (30mm vs. 31mm), and they have been crafted out of an especially durable and heat-resistant steel alloy. These changes, along with alterations to the 450X intake tract, increase the velocity of the incoming air/fuel mixture, thereby enhancing low-end and midrange torque production and throttle response.

Both machines boast a slipper-type double-ring forged piston for a high 12.0:1 compression ratio. Even though the piston measures a whopping 96mm in diameter, it's endowed with an ultra-short skirt - enough so that it resembles a piston crown that's sprouted wrist-pin bosses. As a result, this big-bore single-cylinder engine can reach a rev ceiling off-road riders could only dream about before the advent of Honda's CRF technology. Both 450s also feature a new piston ring groove in 2005 that cuts down on oil consumption - yet another important step in the ongoing refinement process. And taking a page from the design book on Honda's CRF250 series, the 450X incorporates an oil jet that sprays a steady stream of engine oil up to the underside of the piston for an extra measure of engine cooling.

Like all 450 and 250 CRFs, the 450X piston strokes through a durable, low-friction Nikasil(R) cylinder liner, which enhances cooling and reduces weight since it eliminates the need for a separate cylinder liner. The 450's top end incorporates a connecting rod double-carburized for extra toughness, and it utilizes a needle bearing in the big end to maximize high-rpm performance while also enhancing durability.

The low-carbon steel crankshaft features carburized main journals for maximum durability under high engine speeds, and to make the 450 engine tougher than ever, the X-model sports a stronger big-end bearing plus tougher main bearings, and newly added thrust washers surround the crank big-end for extra longevity. Another high-tech carryover, the gear-driven counterbalancer system does double duty by quelling vibration and driving the water pump-again - another testimony to Honda's efficiency in design.

A Keihin 40mm flat-slide carburetor, basically the same unit mounted on the 450 motocrosser, feeds the 450X engine. Large amounts of engine vacuum typically make the flat slide in such carburetors difficult to actuate, so the Keihin versions incorporate four small rollers to reduce throttle pull resistance - a very trick touch. In addition, in keeping with R-model precedent, an accelerator pump and a Throttle Position Sensor (TPS) further enhance accurate fuel metering. On the exit side, a longer exhaust pipe is used (688mm versus 662mm for the 450R), one that is also smaller in internal diameter (38.1mm versus 41mm); both changes enhance torque production and low-end/midrange response. Despite this increase in length the 450X muffler is located farther forward than the unit on the CRF450R, closer to the bike's center of mass, thanks to a more pronounced bend in the header section. The muffler incorporates a USFS-qualified spark arrestor and amazingly enough, in standard form the CRF450X meets current EPA noise limits and CARB exhaust emissions requirements.

Off to a great start

Whether you're a family-type weekend recreational rider or a hard-core off-road racer, you'll surely appreciate the cutting-edge, high-tech electric starter system, complete with a sealed, maintenance-free battery and charging system Honda added to the CRF450X. As testimony to the breakneck pace of technological development these days, the electric starter on the 450X is both smaller in diameter (51mm vs. 62mm) and six ounces lighter than the starter mounted on the 2004 CRF250X - despite being used on a much larger engine. Honda accomplished this feat by using neodymium magnets, also known as rare earth magnets, which are currently the strongest permanent magnets available - and magnitudes more powerful than the more common ferrite magnets used in conventional starter motors. Old-school types need not worry; a kickstart mechanism is still retained for backup purposes. To make manual starting easy, the R-model's hot-start lever has been carried over to the CRF450X and it also features a lightweight, compact internal automatic decompressor system to simplify the starting drill when the occasion arises.

Like the CRF450R, the 450X features vertically split crankcases, and while a host of major design features have been carried over, a number of changes make these cases unique to the new bike. The addition of an electric starter increases engine width a touch (0.66 inch), but any change in the rider interface is barely noticeable thanks to a new clutch pack. This new unit features a thinner clutch pressure plate, which shaves the overall width, so the magnesium clutch cover can be kept as narrow as possible.

In keeping with the newest CRF engine designs, the 450X incorporates a twin-sump lubrication system that separates the engine oil from the oil bathing the clutch and the new wide-ratio five-speed transmission. This dual-supply system ensures a cooler environment for the clutch, while also isolating the engine from any potential contamination caused by clutch and transmission material. Because the total volume of oil circulating to the crankshaft, piston and valve train has been reduced, the oil pump supplying these vital parts can be made commensurately smaller and lighter. Separating these systems also allows the use of a smaller oil pan for reduced weight and less power-robbing oil drag around the crankshaft. In addition, the oil bath surrounding the eight-disc clutch will be subjected to a lower heat load.

Sharp-eyed observers will also note the absence of an oil-level view window in the side case. To power its electric starter and lighting system, the CRF450X incorporates a larger AC generator, which would have obscured a sight window; hence the addition of a dipstick for the 450X. This generator, by the way, also features lightweight and compact neodymium magnets to produce 48 watts max output.

A new wide-ratio five-speed gearbox makes the X-model more adaptable to the huge variety of riding conditions encountered off-road. Final drive gearing is also lower thanks to a 51-tooth rear sprocket that replaces the R-model's 48-tooth sprocket; both bikes use a 13-tooth countershaft sprocket. First gear in the CRF450X is lower (numerically higher) than with the CRF450R, and the X gearbox also tops out with a taller fifth gear:

The primary reduction gears remain the same (2.739, 63/23), but to deal with the jarring obstacles encountered off-road, the CRF450X transmission gears are physically wider and beefier than the R-model gears.

In keeping with the off-road mission of the 450X, the rear wheel is an18-incher to better resist tire punctures. Like the CRF250X, the 450X features the new-style T-ring sealed drive chain, which is narrower, lighter and stronger than conventional O-ring chains.

All the same, but all new

Going strictly by the book, the CRF450X features a fourth-generation Honda aluminum frame - the same designation applied to the CRF450R and both CRF250s. But perhaps a more accurate description of this frame might be a fourth generation, Mark II frame: It incorporates the same overall design as the 450 motocrosser, but has been reengineered and tuned specially for off-road use. In short, few pieces carry over between the frames of the two 450s - the X version is that different.

Why would Honda go through the considerable trouble and expense of building a completely new frame? Simple: off-road events take place in an entirely different world than motocross races, one that demands radically different performance parameters. As Honda's development engineers embarked upon this transformational process, they attacked the toughest off-road areas across America to develop specific frame alterations. And slowly but surely, a new, off-road-specific chassis began to emerge.

Such real-world hands-on adjustments could be applied to the Honda chassis because of its superior basic frame design. Technically speaking, aluminum has a lower specific gravity compared to steel, so there is a much greater latitude of adjustments that can be made compared to working with steel frames. For the 450X, Honda engineers charged full-speed-ahead into an incredibly involved development process.

As a result, the array and degree of alterations made to the CRF450X frame are plentiful. The lower frame rails changed, with .05mm thicker walls than the R cradle. The steering head casting is new. The front frame joint is different. New side pivot plates bolt up on the left and the right sides. Even the frame gussets have changed in shape and size. Such alterations modify the stiffness of the frame members and overall chassis in huge ways; for example, making them resistant to up-and-down flex, while still allowing side-to-side resilience, both in precise increments.

The list of changes goes on and on, with every alteration aimed at crafting a new frame with an entirely different personality, one that yields greater bump absorption over the broad spectrum of obstacles typically encountered off-road. In the end, Honda's engineers accomplished the mission they had targeted for the CRF450X: to create a cutting-edge off-road frame with the same kind of handling confidence found on the CRF450R motocross machine.

The best of the best

Of course, creating a world-class motorcycle chassis entails more than fabricating a superlative frame. All of the top-quality chassis components that make the CRF450R such a potent weapon have been carried over to the CRF450X, but again these elements have been retuned and refined specifically for the new task at hand. The lightweight 47mm inverted Showa(R) twin-chamber cartridge fork is fully adjustable for compression and rebound damping, with 12.4 inches of travel. This new fork features lightweight aluminum damper rods for less unsprung weight, plus new damper specs to soak up the unending processions of obstacles found off-road. The fork springs in the CRF450X are marginally stiffer (0.47 kgf/mm compared to 0.46 kgf/mm) than those used in the R-model motocrosser to compensate for the additional weight of all the X-model's off-road extras. Honda's renowned Pro-Link(R) suspension system graces the rear end, and while it too delivers 12.4 inches of fully adjustable travel like the CRF450R, a new linkage system yields less rising-rate progression, while less compression damping compared to the R-model also helps deliver a plush ride with more compliant rear-end response.

To provide state-of-the-art braking action, the CRF450X boasts large, motocross-style 240mm disc brakes mounted at both ends, with a dual-piston caliper up front. Like the CRF450R, the X-model also incorporates a first-class aluminum swingarm constructed with a dual-axis, double-taper design, plus a stout cast aluminum crossmember for rigidity. Practiced eyes will spy the X-bike's new box-section subframe, which has been strengthened to handle the weight of the de rigueur spark arrestor while also providing more convenient mounting points for affixing the battery and other electrics. As another nice touch, HRC works-type lightweight aluminum spoke nipples help reduce unsprung weight in the wheels.

Other nice touches include a new impeller for the cooling system that runs at reduced pressure for increased durability, larger radiators that provide a 9.4 percent increase in cooling capacity - with a catch-tank located behind the front skid plate for extra protection - and a larger 2.27-gallon fuel tank (the 450 motocrosser holds 1.9 gallons) that should yield a range of more than 50 miles per tank under most conditions. The 450X also features a new seat that's wider and has more rounded edges for improved rider comfort, and it's made with multiple-density foam to keep you smiling during those day-long forays.

As would be expected, the off-road 450X features a sidestand, but take a close look because this is one trick item: the mounting point for the sidestand has been integrated into the rear portion of the left foot peg bracket. Therefore, the sidestand can be quickly removed if desired, or eliminated completely for racing by swapping out the foot peg bracket with one made for the CRF450R.

Motocross-inspired touches a la Team Honda include the durable Renthal handlebar, quick-adjust clutch perch for easy on-the-fly adjustments, and aggressive-looking racer-style plastic bodywork that includes new venting on the right side panel to provide escape hatches for heat from the exhaust pipe. Then there's the trick non-slip seat cover, plus the new quick-access airbox, svelte headlight and slim-line LED taillight and so much more.

With the X model added to the line-up, Honda now offers fraternal twin big-bore four-stroke machines, each outstanding in its own field. The real question here is: Which game do you want to play, motocross or off-road riding? If it's the adventure of off-road riding that lights your fire, the CRF450X will certainly become your favorite son.