2008 Honda Powersports Technology

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Honda Technology

Innovative technology has been a Honda hallmark from the very beginning. Today, Honda's pioneering technology results in a truly unique brand of high-quality, high-performance powersports products.

Engine/Drivetrain Technology

Offset Dual-Pin Crankshaft

Honda engineers first introduced the offset dual-pin crankshaft on the 1983 Shadow® 750 to quell the vibration inherent in its narrow-angle V-Twin engine. Reducing engine vibration increases rider comfort and protects the chassis from fatigue. Honda engineers realized the sum of crankpin offset, plus twice the cylinder V-angle, must equal 180 in order to achieve perfect primary balance. In the case of Honda's mighty VTX1800 with a cylinder angle of 52 degrees, the crankpin offset angle is 76 degrees. The offset dual-crankpin crankshaft design allows the smooth-running 1795cc powerplant to produce peak horsepower at 5000 rpm and peak torque at 3500 rpm while minimizing vibration and allowing a smooth-running engine.

Three-Valve Dual-Plug Combustion Chamber

A major objective of any combustion chamber is rapid, efficient combustion and the more compact the chamber, the easeir this goal can be met. Trying to achieve the highest peak power possible typically requires the flow capability of four valves, but the compactness of a three-valve chamber makes it ideal for other applications. In 1983, Honda debuted the single-overhead-camshaft three-valve cylinder-head design on the VT750C Shadow. In Honda's current generation of V-Twin Shadow and VTX® customs, the combustion chambers feature two intake valves and a single, larger exhaust valve to achieve 20-percent-greater valve area than a similarly sized two-valve engine. This creates high flow capabilities and increased torque at low rpm. The use of two spark plugs shortens the flame path in this compact combustion chamber, contributing to efficient combustion and high power output at lower engine speeds- precisely what custom riders demand.

Programmed Fuel Injection (PGM-FI)

Honda PGM-FI was originally developed on road-racing machines and was first applied to streetbikes such as the CX500T/CX650T Turbo, select GL1200 Gold Wing® models and the exotic NR750 oval-piston sport bike. The essence of this system is the continuous use of several variables to control the injected fuel quantity. Technically, PGM-FI is an n-alpha mapped injection system, meaning that the basic variables are the engine speed (n) and the throttle angle (alpha). Based mainly on those measurements, the system looks upon its fuel map for the fuel delivery corresponding to the n and alpha of the moment. The computer then adjusts this fuel delivery according to four additional variables: intake-port pressure, engine-coolant temperature, intake-air temperature and atmospheric pressure. This fuel-delivery recalculation process is repeated many times per second to ensure the correct mixture for conditions and to provide optimal performance and remarkably crisp throttle response over a wide operating range. Depending on model application, this system uses different-sized throttle bodies, digitally controlled injectors and 3-D ignition mapping.

Dual Stage Fuel Injection System (PGM-DSFI)

First appearing on the 2003 CBR600RR, Honda's high-performance DSFI incorporates HRC-developed two-stage fuel delivery to optimize atomization and cylinder charging at all engine speeds. DSFI system features two injectors per cylinder- one upper and one lower- controlled by an electronic control unit (ECU) that senses rpm and throttle opening. The lower injector enhances low-rpm performance while the upper injector improves mid-range and top-end horsepower. One set of injectors installed at the entrance to the intake ports provides an ideal air/fuel mixture for quick starts and strong, smooth acceleration at low-range settings. At mid-range and higher engine speeds, the system's second set of "showerhead" injectors installed in the roof of the airbox kicks in to deliver extra fuel to cool the higher-volume intake air charge. These injectors also create a denser mixture that improves volumetric cylinder-filling efficiency for stronger acceleration.

Unicam Cylinder Head Design

Honda's Unicam® single-overhead-camshaft (SOHC) four-valve cylinder head first appeared on the 2002 CRF450R. The benefits of the Unicam design are a powerful, yet shorter engine. The liquid-cooled head incorporates a carburized single camshaft that directly actuates two intake valves (the CRF150R utilizes steel intake valves and the CRF250/450 series utilize titanium intake valves). In the CRF250/450 models, the camshaft's single exhaust lobe actuates two steel exhaust valves via a forked, low-friction, roller rocker arm. The Unicam system in the CRF150R is slightly different with the two exhaust valves operating through two separate low-friction roller rocker arms. The SOHC configuration contributes to a compact design that saves weight over a comparable DOHC motor and also permits a narrow included valve angle. This, in turn, flattens the combustion chamber to facilitate free flame propagation, allowing a high compression ratio. A roller bearing on the rocker arms reduces friction and therefore wear, allowing the cam lobes to be narrower- and lighter- than conventional designs. Since less space is taken up in the cylinder head, the camshaft sits lower in the head for a more compact engine and a lower center of gravity.

Longitudinally Mounted Engine

One of Honda's most unique technologies revolves around the powerful efficiency of its longitudinal engine and driveline layout. First introduced on the 1978 CX500 and later on an ATV with Honda's 1995 Foreman® 400, this system sends power to the wheels in the most efficient manner: straight lines. Now a hallmark of Honda's utility ATVs, the longitudinal layout has many advantages: a lower center of gravity, low seat height, increased ground clearance, lighter weight and fewer moving parts than traditional engine driveline systems. By aligning its crankshaft with the vehicle's direction of travel, the longitudinal layout creates a lighter, simpler, more efficient way of sending power to the drive wheel(s). This simplicity may be best seen in the driveline. Using less parts and fewer power-robbing 90 degree bevel drives than conventional designs, this architecture is both lighter and simpler, while delivering more power to the drive wheels from any given engine size. Honda's longitudinal engine allows a low seat height without sacrificing ground clearance, a difficult accomplishment in ATV design.

TraxLok Selectable 2WD/4WD System

Introduced on the 2002 Foreman, TraxLok® is a wheel-drive-changing system that enables the rider to shift between the nimble handling of a two-wheel-drive (2WD) system and the extra traction ability of a four-wheel-drive (4WD) ATV. In all 4x4 Honda ATVs--except the 4x4 Rancher® models which use lever actuation--TraxLok is activated by a magnetic switching mechanism technically known as an electromagnetic mechanical clutch unit (EMCU). This unit actuates a mechanical roller clutch located on the driveshaft near the front differential. This two-way mechanical roller clutch incorporates a series of hardened steel rollers that lock up in a mere six degrees of rotation for a smooth, virtually instantaneous response while either accelerating or decelerating on flat ground or a hill. The system operates in Reverse as well. To ensure smooth operation, the TraxLok system engages only when the speed differential between the front and rear wheels is less than six mph. Once engaged, the system remains engaged on downhills for true 4WD braking. And when the 4WD mode is engaged, a torque-sensitive, limited-slip front differential reduces steering effort for a lighter feel.

Electric Shift Program (ESP)

Honda developed the revolutionary Electric Shift Program (ESP™), introduced on the 1998 Foreman, as a convenient alternative to the conventional manual gearbox. ESP provides push-button upshifting and downshifting. The rider shifts simply and precisely with the press of the upshift or downshift button mounted on the left handlebar. An onboard Electronic Control Module (ECM) monitors information from four sensors--engine rpm, countershaft speed, shift drum angle and shift spindle angle--to control the speed of the electric-shift motor's gear and clutch engagement. Gear-engagement speed varies according to rider style: the transmission shifts more quickly when riding style turns sporty. A Neutral lockout at speeds greater than two mph ensures available engine braking when descending hills. For smooth shifting, the transmission cannot be shifted from Neutral to First gear or Reverse at engine speeds above 3000 rpm. ESP is not battery-dependent; it operates whenever the engine is running. Should the rider ever need to shift manually, the ES model is also equipped with an auxiliary shift lever in the toolkit.

Torque-Sensitive Front Differential

Honda 4x4 ATVs use a clutchless front differential system that automatically sends power to whichever front wheel has the most grip. This system also allows both wheels to maintain essentially the same speed and drive regardless of traction conditions.
It also virtually eliminates torque-steer and drastically reduces the effort
necessary to initiate a turn, thus improving the turning radius and handling.

Electric Power Steering (EPS)

Honda's revolutionary Electric Power Steering (EPS) system was first offered on the 2007 Foreman 500 4x4 ES and represented the world's first EPS for ATVs. The system monitors steering torque and vehicle speed to adjust the levels of steering assist and feel. When stopped or at low speeds, it provides more assistance for light steering effort. As speed increases, the amount of assistance is reduced to provide the appropriate level of feedback. Perhaps the most significant benefit is that the system will provide light and consistent steering feel in both 2WD and 4WD operation. As a secondary benefit, the EPS system acts as a steering damper to greatly reduce undesirable kickback through the handlebars in rough or rocky terrain, reducing rider fatigue.

EPS utilizes a torsion shaft inside the steering stem that moves a sensor up or down in response to steering torque applied by the rider. The sensor detects the core's rate of movement and direction and sends the information to an Electronic Control Unit (ECU). The ECU, following the preprogrammed parameters of a digital control map, regulates current to the electric-assist motor. By providing more or less assistance (torque) to the output shaft, the motor effectively helps the rider by augmenting or minimizing the amount of steering assistance. The Honda EPS system also includes two maps--one for 2WD and one for 4WD--so the rider's feeling is more consistent regardless of mode.

To manage kickback and bump-steer, several measures are employed. First, the ECU "reads" countersteer torque that results when terrain-induced forces through the steering stem counteract rider input. In this instance, the motor's electromagnetic force provides a stabilizing resistance. Even though EPS function may seem unnoticeable at higher speeds, the damping effect is available at all speeds. In addition, rubber dampers on the worm gear shaft reduce steering free-play, giving the system a direct, natural steering feel at all speeds and providing additional cushioning when kickback occurs.

The Honda EPS system is mounted inline with the steering stem and is carried low and close to the center of gravity so handling is not compromised. Adding icing to the cake, Honda's EPS system is also self-contained, totally enclosed and watertight, eliminating the need for any maintenance.

Chassis/Suspension Technology

Pro-Link Rear Suspension

Honda's Pro-Link® rear suspension system offers compliant and comfortable ride quality with a high level of wheel control. It connects a single spring/damper unit to the swingarm via a progressive linkage and delivers an ideal combination of spring and damping rates over a wide range of riding conditions. Initial rates are soft for supple action over small bumps and ripples, while increasingly stiffer rates resist bottoming and maintain rear-wheel control over rougher surfaces.

An additional benefit of Pro-Link is mass centralization because it places the suspension unit close to the center of the motorcycle.

Unit Pro-Link Rear Suspension

Unit Pro-Link™ rear suspension system is patterned after Honda's world-championship-winning MotoGP RC211V®. The upper shock mount is contained within the swingarm rather than being mounted to the frame. With no top frame mount for the shock, this unique system reduces negative suspension energy from being transmitted into the frame, allowing optimum frame rigidity and improved rideability out of corners. It also permits repositioning of the fuel tank lower and closer to the machine's center of mass.

Pro Arm Rear Suspension

Honda's unique Pro Arm® is a functional and stylish departure from a conventional fork-type rear swingarm. Developed from Honda's championship-winning racing experience, the cast-aluminum Pro Arm offers balanced rigidity, light weight, simple rear-wheel removal and easy chain adjustability. Other benefits include added room for exhaust routing, easy shock access and minimal unsprung weight.

Honda Electronic Steering Damper (HESD)

The compact Honda Electronic Steering Damper (HESD) helps maintain smoothly predictable high-speed handling while having remarkably little effect at slower speeds. Given its size, the HESD unit can be easily shrouded beneath the fuel-tank cover (CBR600RR), immediately behind the steering head where it is mounted to the frame and connected to the upper triple clamp by an articulating arm that moves the unit's damping vane within its oil chamber.

In actual use, the HESD offers an exceptional level of technological sophistication and seamless operation, and allows the motorcycle to achieve new levels of handling performance by incorporating steering geometry settings and a shortened wheelbase that would otherwise prove unfeasible without this innovative system.

Hollow Fine Die-Cast (DC) Frame Design

With the introduction of the 2003 CBR600RR, Honda made a huge leap forward in the manufacturing of aluminum frames with the advent of Hollow Fine Die-Cast technology. Honda has long pioneered the use of all-aluminum frames for streetbikes and off-road motorcycles. Each requires different construction and tuning but they often employ a collection of castings, forgings, pressings or extrusions. With previous conventional Fine DC techniques, the thinnest walls possible had been 3.5mm. With Honda's Hollow Fine DC technique an unprecedented 2.5mm wall thickness is possible, providing engineers with even greater latitude to tune frame members to specific rigidities to enhance handling. On the 2007 CBR600RR, Honda's engineers incorporated next-generation technology to reduce the number of welded-up sections from 11 to only four larger castings. While all sections are hollow-formed with approximately the same 2.5mm wall thickness as used in the previous frame, the new frame is more than 1.1 pounds lighter as well as being stronger, slimmer and more compact.

Twin-Spar Aluminum Frame

Borrowing from the dominant GP bike of its era, the NSR500, Honda introduced a race-inspired, twin-spar aluminum frame on the 1986 VFR750F. For confidence-inspiring handling, it is crucial that the frame's major load path--steering head to swingarm pivot--be as direct as possible. No other frame does this as effectively as Honda's twin-spar design. In this setup, two large-section aluminum beams run directly from the steering head to the swingarm pivot plates--or in the case of the Interceptor, the engine case. Honda brought twin-spar aluminum frame technology to motocross racing with the radical 1997 CR250R. With each subsequent design generation Honda has fine-tuned its aluminum-frames, varying wall thickness of the frame spars, castings and corresponding swingarms to optimize torsional and lateral rigidity, achieve light weight, durability and precise handling performance.

Inverted Twin-Chamber Cartridge Fork

The 1997 CR250R sported new front suspension in the form of a 47mm inverted twin-chamber Showa cartridge fork with 16 positions of rebound and 16 positions of compression adjustability. This is a sealed cartridge design that unlike a conventional cartridge does not allow the fork oil to mix with the oil outside the cartridge. The fork spring is located below the cartridge and the compression adjustments are made at the top of the fork. In addition, the inner surfaces of the front fork outer tubes receive the same honing treatment as a "works-type" fork stanchion for low-friction operation.

Honda Multi-Action System (HMAS)

Motocross damper units need to be big to pump a lot of oil and cushion hard landings, but streetbikes require something different. Honda engineers developed Honda Multi-Action System (HMAS), a technology of lower pumped-oil-volume dampers that provides a major contribution to tracking response and ride quality. Both the HMAS cartridge front fork and rear damper feature Honda-exclusive internal piston construction. This innovative design employs smaller-diameter pistons to keep oil velocity high for improved damping characteristics and an expanded range of adjustability.

Anti-Lock Braking System (ABS)

Honda's first ABS-equipped production motorcycle was the 1991 ST1100. The system utilized modulators--one each on the front and rear wheels--driven directly by specially developed electric motors. In operation, an Electronic Control Unit (ECU) monitors wheel and vehicle speed. If one or both of the wheels approach a locking condition, the modulators, via a signal from the ECU, lower hydraulic pressure by acting directly on the brake piston(s). As wheel speed reapproaches motorcycle speed, the hydraulic pressure is increased. This entire process is repeated numerous times in just one second, resulting in optimal braking pressure and enhanced rider control. A second type of ABS for scooters features a circulating-type modulator with a single motor-driven pump that generates hydraulic pressure regulated by an ECU-activated solenoid valve to control both front and rear brakes. Today, Honda ABS is offered optionally on Linked Braking System™- and Combined Braking System-equipped machines.

Linked Braking System (LBS)

Honda's first street motorcycle with linked braking was the 1983 GL1100 Gold Wing. Called Unified Braking at the time, the system was derived from a "works" RCB1000 that won numerous endurance race victories in 1976. Today Honda offers highly sophisticated LBS™ as exemplified by the current Gold Wing's dual full-floating 296mm front discs with three-piston calipers and single ventilated 316mm rear disc with one three-piston caliper. A second master cylinder and a three-stage proportional control valve couple the three-piston calipers of the dual-front and single-rear brake discs. On the Gold Wing, using the front brake lever activates the outer two pistons of the front right-side caliper and the center piston of the front left-side caliper and, acting through the secondary master cylinder and an inline proportioning valve, the outer two pistons of the rear caliper. The rear brake pedal operates the center piston of the rear brake caliper, the center piston of the front right-side brake caliper and the outer two pistons of the front left-side caliper. A delay valve sensitive to the rider's pedal pressure smoothens front-brake engagement. Other models offer variations of this system.

Combined Braking System (CBS)

Honda scooters employ a linked braking system called CBS that applies front braking force whenever the rear brake is operated. On the Silver Wing, equipped with a three-piston front caliper and a twin-piston rear caliper, rider application of the front-brake lever activates the two outer pistons of the front caliper. Application of the rear-brake lever mounted on the left handlebar activates the dual pistons of the rear caliper and the center piston of the front caliper. When only the rear-brake lever is used, an inline delay valve smoothens application of the front-caliper piston.

Miscellaneous Technology

GPScape

Honda's GPScape® employs the fundamentals of Global Positioning Satellite technology. A radio receiver picks up signals from at least four of 24 ground-controlled satellites orbiting the Earth. The signals allow the receiver to calculate its distance from the satellites and from that it calculates the machine's exact position. The weatherproof GPScape system features mode and waypoint (WPT) buttons. Selecting GPScape also causes an arrow circumscribed by a circle to appear on the LCD display. The WPT allows the rider to select and store a waypoint- that is, the current location. That locks in your location so you can find the way back to that point. The arrow on the LCD face points the direction to the chosen waypoint. As an added convenience, GPScape can store up to 100 waypoints. And GPScape can recall any of its 100 waypoints for up to 10 years; even if the vehicle's battery goes dead, the information stays in the GPScape system's memory for a decade. What's more, selecting the compass function via the mode button transforms the circumscribed arrow on the LCD panel to a compass. Users can also program in specific latitude and longitude figures. GPScape runs off the vehicle's battery, which means its backlit display will stay illuminated at night.

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