New for 2007
- New larger 41mm Keihin FCR carburetor.
- New smaller exhaust valve for improved flow and smoother power delivery.
- Engine decompression system is lighter and more compact.
- New link-type front brake master cylinder improves front braking power by 15 percent.
- New Dunlop 742FA front tire for improved turning feel and traction.
- New subframe allows the muffler to be mounted farther forward for better mass-centralization.
- Lighter rear chain guide.
- Stronger clutch basket and clutch center for improved wear resistance.
- New ignition map to match changes to carburetor and cylinder head.
- New one-piece cover protects throttle cable by keeping out dirt and water.
- Carburetor features a new accelerator pump and linkage for improved throttle response.
- New exhaust system placement improves mass-centralization.
- New front suspension valving for improved bump absorption.
Engine/Drivetrain
- Powerful engine churns out 55 bhp at 9000 rpm and 36.9 lb./ft. of torque at 6500 rpm. Power is produced across a wide rpm band for easy-to-control operation.
- Auto decompression and hot restart system make starting easy in all conditions.
- Liquid-cooled four-valve Unicam® 449cc engine produces more than 120 hp per liter while maintaining Honda's legendary dependability and simplicity.
- Compact, lightweight engine assembly weighs only 63.8 pounds.
- ACG cover made from magnesium for reduced heat buildup and lighter weight.
- Unicam valve train provides the light weight of a compact single-cam drive 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 36mm titanium intake valves. The camshaft exhaust lobe actuates two 30mm steel exhaust valves via a forked, low-friction roller rocker arm. A separate cam holder contributes to the compact design, which allows a remarkable 21.5 degrees included valve angle and saves 13.3 ounces over a comparable DOHC system.
- Lightweight titanium intake valves permit use of smaller valve springs, reducing overall engine height and saving 15.2 grams per valve compared to a steel valve design.
- Unique internal pin-rotation-type auto decompressor produces a lightweight, compact system that provides superb cold-starting and hot-restarting operation.
- Crankshaft is made of high-strength, low-carbon steel with carburized main journals for maximum durability at sustained high-rpm operation.
- Forged 12.0:1 compression slipper piston is more than 4.5 ounces lighter than a conventional design, revving quickly while maintaining excellent cylinder sealing and high-rpm power.
- Double-carburized connecting rod utilizes a big-end needle bearing 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.
- 41mm FCR-type carburetor features four rollers on the flat slide, resulting in very light throttle effort, smooth operation, crisp throttle response and excellent rideability. Bottom of float chamber is designed to allow more fuel to pass to the main jet.
- An 8-bit digital CPU incorporates the capacitive discharge ignition (CDI), producing immediate data calculation and extremely accurate ignition for maximum performance.
- 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 to the engine oil and reduces the amount of circulating oil and the required size of the oil pump.
- Vertically split crankcases feature a built-in oil pump, reducing weight 5.1 ounces compared to a conventional design.
- Exhaust system features a titanium header and heat shield. The repackable silencer is aluminum with a stainless steel connector pipe.
- Long-lasting silencer packing.
- Narrow dual radiators provide significantly more surface area and more effective heat dissipation compared to a single-radiator design.
- 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.
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 thin 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.
- Front and rear wheels feature HRC works-type lightweight aluminum spoke nipples.
- 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 significant rigidity to withstand torturous track conditions.
- Lightweight 47mm inverted Showa twin-chamber cartridge fork with aluminum dampers feature settings unique to the CRF®. The fork offers 12.4 inches of travel, 16-position rebound and 16-position compression damping adjustability. Front fork stanchions' inner surfaces use same honing process as on works bikes for reduced friction.
- Pro-Link® single-shock rear suspension system features a fully adjustable Showa rear damper and 12.5 inches of wheel travel, separate low-speed (13 positions) and high-speed (3.5 turns) compression damping adjusters and 17-position rebound damping adjustability.
- Rear shock's damper piston diameter is 50mm for consistent performance under demanding riding conditions.
- Compact dual-piston front brake caliper has been designed for a weight savings of more than 1 ounce. 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 rear master-cylinder reservoir and hose.
- Link-type front brake master cylinder provides strong braking while using a light-weight brake rotor.
- Large 240mm front and rear disc brakes.
Additional Features
- Frame design allows sidecovers to have larger air-intake ducts, contributing to significant airflow increase in the mid- and upper-rpm ranges.
- 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 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.
- Brake pedal and shift lever 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 and corrosion resistant, provide excellent grip and fold for extra ground clearance.
- Rear brake pedal and shift lever are made of lightweight aluminum.
- Adjustable front brake lever for maximum control.
- Quick-adjust clutch perch for easy cable adjustment.
- Aluminum 971 bend Renthal handlebar as standard equipment is rubber-mounted to reduce rider fatigue and improve comfort.
- CR® handlebar holders provide three different mounting positions: Standard CRF450R holder 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.
- Dunlop 742FA front and 756 rear tires for improved traction and cornering.
- 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.
- Repackable silencer for maximum performance and minimal noise.
- Comfortable, durable controls and high-quality fasteners.
- Stainless steel clutch cable for long life.
- Honda Racing™-inspired colors and graphics.
- Purchase of a new, previously unregistered Honda unit by an individual retail user in the United States qualifies the owner for a one-year complimentary membership in the Honda Rider's Club of America™ (HRCA®). Benefits include online access to the Honda Common Service Manual, six issues of the bimonthly Honda Red Rider™ magazine, travel discounts, trip routing, MSF reimbursement, plus access to the HRCA Web site (www.hrca.honda.com). Look for the HRCA support team at select off-road events across the country. For details on the HRCA, dealers should call (310) 783-3958, 8:30 a.m. to 5 p.m. Pacific Time.