2011 CBR250R DEVELOPMENT
Currently, the fundamental order within the U.S. motorcycle market automatically ushers 250cc street bikes into the beginner-bike niche. However, it wasn't always so; plenty of longtime riders currently roaming the roads still recall how quarter-liter bikes evaded such tight pigeonholing decades ago. Moreover, in most markets around the world today, 250s serve as mainstream motorcycle transportation with plenty of merit to stand on their own. Also, up until the last few years, purpose-built 250cc race bikes continued to compete in AMA and World GP competition, providing spectators and competitors with good, tight racing action. As a rule, such machines offered good enough horsepower but really shined in terms of excellent handling and remarkably light weight.
And so Honda embarked upon a mission to build a modern-era 250cc street bike: The CBR250R, a machine that offers enough power response to produce an entertaining ride while truly shining in terms of sporty handling and light weight--all at an eminently affordable price. Such universal qualities appeal to all riders. In order to achieve such an outcome, the CBR250R design incorporates a slew of high-tech features--including 27 patented technologies within the engine and chassis.
CBR250R Engine Design
The CBR250R engine development took shape by aiming at a global single-cylinder design that transcends all boundaries; a next-generation four-stroke liquid-cooled powerplant that would deliver sporty and torquey performance not only at low engine speeds but also in the high-rpm range, while still being smooth-running. Economical operation in terms of fuel efficiency and simple servicing was also a must-have characteristic. In addition, light engine weight and compact dimensions would set the stage for superior handling traits.
To fulfill such sport performance requirements with an eye toward efficient operation, a dual overhead camshaft layout was selected as the valve actuation system. DOHC designs improve combustion efficiency by reducing the weight of the reciprocating portion of the valves. This design also allowed Honda's engineers great freedom in choosing the included valve angle, the port shape, and the shape of the combustion chamber--all key elements for optimal performance. In addition, the choice of a DOHC configuration contributed to improved product appeal as a sports bike as well as adding sheer performance.
In the CBR250R's valve train, a roller rocker arm was adopted in combination with the DOHC engine configuration--a world's-first application that has been patented. This unique combination produces a low-friction valve train with a smaller cylinder head and an ultra-compact layout for the roller rocker arm. The choice of a shim design for valve tappet adjustment reduced the rocker arm weight, while internal engine friction was further reduced by setting the valve spring load to a low level. For ease of maintenance and reduced operating costs, the valve shims can be replaced for valve adjustment maintenance without removing the camshafts. This design also allowed the engineers the freedom to incorporate a pent-roof combustion chamber with a narrow included valve angle for enhanced combustion characteristics.
To reduce the flow of blow-by gasses and minimize oil consumption, a spiny sleeve design was adopted for the cylinder sleeve. With this configuration, small spines have been added to the outer surface of the cylinder sleeve to improve cooling performance and help reduce distortion of the cylinder's inner shape. In addition, centrifugal casting allows a thin, uniform wall thickness, which aids weight reduction. For emissions reductions, an O2 sensor is combined with the built-in air injection (AI) system, and a catalyzer is fitted inside the exhaust pipe to comply with emissions standards.
Engine Performance
To enhance engine performance, a very oversquare, short-stroke engine (bore x stroke: 76mm x 55mm) was chosen to improve responsiveness. The resulting bore and stroke are commensurate to those of the CBR1000RR, Honda's high-performance supersport literbike. The 30mm intake valves are a mere half-millimeter smaller in diameter than those used in the CBR1000RR, while the 24mm diameters of the exhaust valves match exactly between the two bikes.
To reduce reciprocating weight and friction, the CBR250R piston carries a very short skirt and features a slick molybdenum coating. Friction was further reduced by creating light striations on the piston to facilitate retention of lubricating engine oil, lowering the tension of the piston rings, and applying a smooth, shot-peen-hardened finish to the piston pin. Another slick bit of design work further reduces engine friction: The cylinder centerline is offset from the center of the crankshaft 4mm toward the exhaust side. Doing so reduces the lateral resistance generated between the piston and the cylinder during the power stroke. Granted, it's a small increment, but it's an ingenious design element exemplifying attention to detail that yields free benefits.
To boost power output from low- through high-rpm ranges, charging efficiency was improved by straightening flow pathways from the air cleaner to the exhaust pipe. The valve stems have been made thin (4.5mm) so as to not impede intake and exhaust flow, although valve diameters are large for both sets of valves. This valve design is coupled with a wide opening angle and a high-lift cam to improve intake/exhaust efficiency. To achieve output characteristics that are easy to handle at low speed and smooth rev-up at high rpm, the intake/exhaust systems were thoroughly analyzed and tested to adopt the ideal port/pipe length and diameter.
In designing the crankshaft, no efforts were spared to reduce weight in order to lower the inertial mass while achieving additional weight reduction in the connecting rod. This new-generation crankshaft helps create an engine full of high-quality feel while maintaining high output. First, a metal bearing (half-split, press-fit) was chosen for the crank journal for the first time on a Honda single-cylinder motorcycle. A cast-iron bushing was selected for the crank bearing section in order to improve the rigidity of the crankcase housing and control changes in the crank journal's oil clearance arising from thermal expansion, while improving engine quietness at the same time.
Selection of a built-up -type crankshaft allows the big end of the connecting rod to use a low-friction roller bearing, and the optimal crank web shape was realized as a result of a computer analysis of strength and rigidity. In sum, these measures ensure high rigidity on a par with a solid-type crankshaft.
To reduce engine vibration, a primary balancer shaft is incorporated into this cutting-edge single-cylinder engine. It's placed so close to the crankshaft that the balancer weight passes between the two crank weights--a design that keeps the engine as compact as possible while helping improve mass centralization. Also, crankshaft rigidity is enhanced further and quietness is improved by placing the engine counterbalancer's driving gear on the right cover inside the clutch housing--a design that narrows the distance between the left/right crank bearings and efficiently places a load-bearing ball bearing at the tip of the crankshaft's right side.
Chassis
With the CBR250R chassis, Honda's engineers targeted agile handling, solid tracking and sporty, responsive steering traits as key objectives. Toward that end, the newly developed lightweight and compact engine, a short 53.9-inch wheelbase, an optimized front/rear weight distribution, and a focus on mass centralization all helped shape the CBR250R into a handling star. At the same time, weight reduction and reduced vehicle vibration were achieved by optimizing the position of the engine mounting points and the frame rigidity/flex balance.
The CBR250R engine bolts up to a diamond-configuration truss-braced twin-spar tubular steel frame that is lightweight while also offering plenty of frame rigidity for optimal handling. The 37mm front fork offers a generous 4.65 inches of travel, and the Pro-Link® single-shock rear suspension uses a linkage system to provide rising-rate travel characteristics for a soft, comfortable ride during the initial portions of travel, with the damping forces increasing progressively as wheel travel is extended. In addition, the shock offers five-position spring preload adjustability. Together, these components combine to provide impressively agile handling along with rider comfort.
Powerful braking capabilities come via a front brake consisting of a twin-piston floating caliper clamping down on a large, 296mm floating disc and a rear brake consisting of a big 220mm disc and a single-piston caliper. As an option, the CBR250R can be had with Combined ABS, which combines a front/rear-wheel interlocking brake system with an anti-lock brake system (ABS). This Combined ABS is a Honda-original brake system in which the front/rear-wheel connection generates a braking force distributed between both wheels when the brake pedal is actuated. However, for a more sporting response, when the front brake lever is applied, the front brake alone functions independently without actuating the rear brake.
The CBR250R with Combined ABS features a three-piston caliper in front, front/rear wheel speed sensors that detect the condition of the vehicle, and an ABS modulator with a built-in Electronic Control Unit. The ECU processes information from the wheel speed sensors and controls the flow of hydraulic pressure to the caliper. This advanced braking performance was achieved with an eye toward optimal handling by placing heavier items, such as the ABS modulator, near the bike's center of gravity.
Sporty riding ergonomics position the rider into a slight forward lean, just the right amount to help counter the oncoming airflow at about 50 mph and up, and there's plenty of legroom. Such a riding position proves eminently comfortable in just about every riding situation, and the roomy seating also makes it easier to maneuver the bike. The seat sits only 30.5 inches high, an easy reach to the ground that provides a rider-friendly perch especially suited to beginners. The fairing and windscreen combine to offer good coverage, forming an excellent still-air pocket that is arm to arm in width and up to about collarbone level on a 6-foot-tall rider. Also, the fairing and windscreen have been carefully shaped to produce a wind flow at freeway speeds that's smooth and free of turbulence and back-eddies. And this CBR has an ideal angle to the handlebars--it's very comfortable for long stints in the saddle.
Unmistakably supersport-inspired in its styling, the CBR250R's aggressively sculpted fairing sweeps up from the front of the bike to a slim, light and purposeful tail. The bike's lines are at once dynamic and sophisticated, communicating the machine's dual personalities: exciting small-capacity sportbike and practical all-rounder.
No doubt the new CBR250R serves as a very well-rounded package, a fantastic fit for riders new to the sport. It offers stellar handling along with satisfying power, which beginners will appreciate. The CBR's light weight pays dividends in all sorts of riding conditions, and it offers a power feel that is distinctly entertaining; a chassis that feels modern and up to date with crisp handling, sound suspension and strong brakes; and an extremely comfortable riding position that's both practical and sporty.
There's a reason racing machines are small and light; these are two qualities that make genuine racers so much fun to ride. The CBR250R puts these qualities to best use on the street.
CBR250R
The all-new 2011 CBR250R brings a fresh take on the fun side of motorcycling, one that will appeal to a wide range of riders. Beginners and experienced hands alike will key in on the extreme versatility of this sporty, easy-to-ride and affordable new offering from Honda.
Thanks to its extremely efficient 249cc liquid-cooled single cylinder engine--an all-new design featuring a sophisticated four-valve DOHC cylinder head, engine counterbalancer, PGM-FI fuel injection and more--this dependable and lightweight machine delivers nimble handling, a broad spread of easily accessible power and low operating costs all in one. Whether the day calls for a commute to work, quick trips around town or all-day explorations in the countryside, the CBR250R offers as much fun per mile as anything around, all at a price that just about anyone can afford.
Features/Benefits
- The sophisticated, all-new 249.4cc single-cylinder engine is thoroughly modern in design thanks to its dual overhead camshafts driven by a Hy-Vo-type chain, forked roller rocker arms, four-valve head, shim-style valve adjustment, counterbalancer shaft and liquid cooling.
- The CBR250R's single-cylinder engine produces a remarkably broad torque curve with peak torque generated at an easily accessible 7000 rpm. Peak horsepower kicks in at 8500 rpm, well before the 10,500-rpm redline--further testimony to the wide spread of power. Such power characteristics facilitate easy, responsive operation while also returning impressive fuel economy.
- The crankshaft runs in plain bearings for quieter operation, and the big end of the connecting rod spins in a needle bearing.
- Gear-driven counterbalancer shaft helps quell engine vibrations for rider comfort. It's located so close to the crankshaft that the balancer weight passes between the two crank weights to keep the engine as compact as possible while boosting mass centralization.
- Engine countershaft sits lower than the mainshaft to further reduce the front-to-back engine dimension.
- Programmed Fuel Injection (PGM-FI) continuously monitors several variables to ensure the correct fuel mixture for the existing riding and atmospheric conditions, thereby delivering optimal performance and remarkably crisp throttle response over a wide range of operating conditions, plus increased fuel economy.
- PGM-FI system incorporates an Idle Air Control Valve (IACV) to minimize torque reaction and smooth responses to small changes in throttle position. This is accomplished through gradual reductions of air and fuel intake when the throttle is opened and closed.
- Thanks to its single-cylinder configuration, the CBR250R incorporates a light, compact and fuel-efficient powerplant, resulting in an overall package that is remarkably compact and nimble for intuitive handling dynamics.
- The six-speed transmission works in concert with the engine's broad power delivery to produce quick acceleration plus admirable fuel economy during top-gear cruising.
- Diamond twin-spar steel frame plus a 37mm front fork and Pro-Link® single-shock rear suspension provide impressive handling and a comfortable ride.
- ABS version available for enhanced braking characteristics.
- Base weight of only 359 pounds gives the CBR250R outstanding maneuverability and helps instill rider confidence.
- Stylish full fairing with windscreen deflects the oncoming wind to boost rider comfort.
- Sporting ergonomics keep the rider perched in a well-balanced seating position to deliver a natural feel and comfortable stance even over daylong rides.
- Full-sized 17-inch cast wheels return big-bike feel and handling traits.
- Fuel capacity of 3.4 gallons gives the CBR250R a cruising range of more than 200 miles.
- An external fuel filter maximizes fuel tank capacity while also easing fuel filter maintenance.
- Grab rails on the tail section are designed to fit gloved hands, giving passengers a dedicated handhold while riding two-up.
- A handy underseat storage area adds to the CBR250R's versatility.
- Multi-function digital instrument pod includes speedometer, tachometer, engine temperature display, fuel gauge, clock, odometer and trip meter.
- Exciting colors: Metallic Black and Red/Silver.
Honda Genuine Accessories†
- Passenger Seat Cowl
- Carbon Fiber Tank Pad
- Carbon Fiber Fuel Lid Cover
- Outdoor Cover
† WARRANTY: Because we're so confident in the quality of each of our Honda Genuine Accessosries, we're pleased to offer one of the best warranties in the industry. Warranty begins on the day accessories are purchased by the customer. Gold Wing®, ST1300 and Valkyrie®: 3 years. NT700V, Big Red™, DN-01, Dual-Sport, Cruisers, Standards, Sportbikes, Scooters, ATV and PWC: 1 year.
2011 Specifications
Model: CBR250R / CBR250R ABS
Engine Type: 249.4cc liquid-cooled single-cylinder four-stroke
Bore and Stroke: 76mm x 55mm
Compression ratio: 10.7:1
Valve Train: DOHC; four valves per cylinder
Induction: PGM-FI, 38mm throttle body
Ignition: Computer-controlled digital transistorized with electronic advance
Transmission: Six-speed
Suspension
Front: 37mm fork; 4.65 inches travel
Rear: Pro-Link single shock with five positions of spring preload adjustability; 4.07 inches travel
Brakes
Front: Single 296mm disc
Rear: Single 220mm disc
Optional ABS
Tires
Front: 110/70-17 radial
Rear: 140/70-17 radial
Wheelbase: 53.9 inches
Rake (Caster Angle): 25.0°
Trail: 95mm (3.74 inches)
Seat Height: 30.5 inches
Fuel Capacity: 3.4 gallons
Colors: Metallic Black, Red/Silver
Curb Weight*: 359 pounds / 368 pounds (ABS)
*Includes all standard equipment, required fluids and full tank of fuel--ready to ride.
Meets current EPA standards.
Models sold in California meet current CARB standards and may differ slightly due to emissions equipment.
Specifications subject to change without notice.
CBR250R Global Production Story
Avid Honda fans likely recall that American Honda first opened its doors way back in 1959. Here's a tougher Honda trivia question: When and where did Honda first produce products outside of Japan? Answer: In 1963, Honda began producing motorcycles in Belgium. Four years later, Honda cranked up production of motorcycles at another location--in Thailand--and this long-established source is where the all-new 2011 CBR250R originates. Next came production plants in Malaysia, Taiwan, Mexico, Indonesia, the Philippines, Brazil and Italy--all in the 1960s. It wasn't until 1979 that Honda began producing products in the USA. And now the total stands at 20 countries the world over where Honda has established manufacturing plants.
All of which underscores the fact that since its early years, Honda has focused on serving a global market. Naturally, consumer needs vary from region to region. Based on a commitment to build products close to the customer, Honda has steadily pursued local production. By focusing on localization early on, even in the areas of product development and sales, Honda has been able to respond to changes in product demand and supply more promptly, and quality and cost competitiveness have increased in each market. To deliver products that satisfy customers in all regions, Honda established a manufacturing system that responds to customer requests rapidly and with great flexibility at all production bases around the world.
The CBR250R will be launched by Thai Honda in 2011 as a global model for export to a wide range of places, including the ASEAN (Association of Southeast Asian Nations) countries, Japan, Europe, North America and Australia. The 5400 associates at Thai Honda have now reached an annual manufacturing capacity of 1.5 million motorcycles and scooters, and total motorcycle/scooter output from Thai Honda since 1967 far exceeds 18 million units.
Honda Worldwide Production Timeline (Outside Japan)
1963 - Motorcycle production begins in Belgium
1967 - Motorcycle production begins in Thailand
1969 - Motorcycle and automobile production begins in Malaysia
- Automobile production begins in Taiwan
1971 - Motorcycle production begins in Mexico
- Motorcycle production begins in Indonesia
1973 - Motorcycle production begins in the Philippines
1976 - Motorcycle production begins in Brazil
1977 - Motorcycle production begins in Italy
1979 - Motorcycle production begins in U.S.
1980 - Automobile production begins in U.S.
1985 - Motorcycle production begins in India
1986 - Motorcycle production begins in Canada
- Motorcycle production begins in Spain
- Power Products production begins in France
1988 - Automobile production begins in New Zealand
- Lawnmower production begins in Australia
1992 - Automobile production begins in U.K.
1994 - Automobile production begins in Pakistan
1996 - Automobile parts production begins in China
1998 - ATV production begins in U.S.
2006 - Motorcycle production begins in Argentina
- Motorcycle production begins in Pakistan
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