2014 Honda CBR650F Development

Supersport styling, nimble handling, easily accessible power, excellent rider comfort, plenty of versatility and a great price—we're talking high-level fun factor here, an all-new motorcycle that appeals to your practical side that's also a blast to ride, no matter where that ride takes you. Commuting, a weekend ride in the country with friends, solo or with a passenger, the all-new CBR650F does it all.

The CBR650F is a sport bike that gives you maximum bang for your buck, and offers the kind of performance and quality only Honda delivers. Its 649cc engine is brand new from the sump up, and this torque-laden inline four-cylinder is especially compact. This facilitates optimum positioning in the chassis to enhance weight distribution, and create a slim profile and responsive handling. 

Powerband priorities focused on the low- and mid-speed ranges used most frequently for street riding, rather than the harder-edged attributes of a supersport bike that might see lots of track time. As a result, the power jumps in quickly low in the rpm range, right where riders need it on the street. Yet at higher engine speeds, the CBR650F still packs a smooth, strong punch. 

The basic configuration and dimensions of this liquid-cooled four-valve engine were initially developed using computer-assisted engineering (CAE). The cylinder bank cants forward at a 30-degree angle to help lower the bike's center of gravity. This angle also facilitates a remarkably straight shot from the air intakes through the air cleaner, to the intake ports and out the exhaust pipe. Net result: a reduction in the intake and exhaust resistance, which helps boost power output and fuel efficiency.

Tapered intake air funnels and active streamlining of airflow through the air cleaner—plus use of a large panel-type filter element—provides ample air intake. The four exhaust pipes curve down in an attractive, flowing shape and tuck in tightly to the engine—moving the oil filter to the rear of the engine allows this compact arrangement. The thermostat, in turn, now mounts at the front of the engine to shorten the engine coolant path, adding to the engine's compact design. A large, two-chamber collector box beneath the engine helps make this four-into-two-into-one exhaust system notably short and compact; keeping this weight low and close to the center of mass helps promote nimble handling.

Chain-driven dual overhead camshafts and bore and stroke settings of 67mm by 46mm were chosen for optimal power. The DOHC layout allows a large degree of freedom for creating an efficient combination of included valve angle, port shape and combustion chamber design. A silent-type cam chain with tough vanadium surface treatment applied to the cam chain pins helps reduce friction to minimize parasitic power losses.

Valve timing was set to minimize the overlap when intake and exhaust valves are both open to promote fuel efficiency. The intake valves measure 27.5mm in diameter while exhaust valves with a diameter of 22.5mm are used. The piston pins and connecting rods are treated with a special friction-reducing protective coating for greater durability and efficiency.

Like Honda's supersport bikes, the CBR650F stacks the transmission shafts in a vertical plane to shorten overall engine length and further centralize mass. Breathing holes pierce the walls between crankcase journals to reduce pumping losses during piston travel. For the cylinders, thin-wall sleeves are formed through centrifugal casing to minimize cylinder strain while achieving a lightweight and compact design.

Lightweight aluminum engine hangers are used to bolt the powerplant into the twin-spar diamond-shape steel frame, with the engine acting as a stressed member of the chassis—an efficient layout for enhanced handling. The main frame tubes, measuring 64mm by 30mm, are oval in cross-section for added strength in the key vertical axis, while yielding tuned flex in other dimensions for added rider comfort. Thanks to the compact engine design, the engine could be positioned forward in the chassis to achieve close to a 50/50 weight distribution between front and rear axles for a balanced feel. Forged-molding pivot plates eliminate a need for frame covers in the pivot area, which helps minimize frame width in that crucial rider/bike interface point.

The rider position feels natural and spacious with just a slight forward lean, and the full fairing deflects a substantial portion of the oncoming wind stream. The one-piece seat requires a reach of only 31.9 inches down to the ground; careful seat shaping makes it feel like that distance is even less.

A 41mm fork handles suspension duties up front; it yields a comfortable 4.7 inches of well-controlled travel. In back, the single-shock rear suspension is actuated directly by the strong yet lightweight aluminum swingarm for 5.0 inches of rear-wheel travel. Shock spring preload is adjustable in seven steps to accommodate variations in load and riding conditions.

Wave-type dual front 320mm disc brakes and a 240mm rear give strong stopping power and lend a stylish touch while also saving unsprung weight. The front brakes use twin-piston calipers, while the rear is a single-piston type. Honda's ABS system is available for more confident stopping in challenging conditions.

The instrument panel on the CBR650F is a full LCD multi-function digital meter that includes speedometer, tachometer, odometer/A&B tripmeters, fuel gauge and clock. This display can also show average and instantaneous fuel consumption. Other thoughtful touches include an LED taillight, an underseat utility area for a modest bit of storage space, a front brake lever with six-step adjustability, and a fuel tank hinged at the front for easy maintenance access. 

Conceived from the ground up as a fully integrated package, one in which the new engine design complements the new chassis configuration to create a truly fun motorcycle, the CBR650F appeals to a wide variety of riders. Its supersport style reflects its nimble handling and responsive engine, adding top-level comfort and remarkable versatility you won't find in pure supersport machines. A friendly ride that stirs the heart no matter where you're headed is the embodiment of the Honda CBR650F.