2003 ST1300/ST1300 ABS Development

Sport-touring is something of an abstraction. A motorcyclist taking off for a ride doesn't think, "I believe I will go sport-touring today." Instead, it's more like, "Today I'm riding long, and I'm riding hard. Let's roll." And that's what the 2003 Honda ST™1300 is all about: Ride hard, ride long.

When Honda first introduced the ST1100, that was its original premise. And it played well. As Cycle magazine described in the initial test in 1990, "The ST's mission is sharply and narrowly defined: comfortable high-speed, long-distance passage." For more than a decade, the ST1100 fulfilled that mission statement admirably, and its 12-year life span speaks volumes of its competence and popularity. But now, the next-generation ST comes to elevate that original premise to a higher level with a whole new set of credentials.

To that end, Honda infused the new 1300 with abilities that expand the ST's sport potential, while also enhancing its long-distance range and comfort. Both at once? How can that be? In a word, technology. Indeed, the new ST benefits from a big dose of Honda high-tech from front to back, top to bottom, chassis and engine alike. Lessons learned at the race track have been adapted to this open-road specialist, all of which make this successor more able--and more fun--than ever before.

Beginning with the powerplant, the 2003 ST boasts an engine that's completely new and more than 16 percent larger in displacement, 1261cc compared to the previous 1084cc. Because the original ST1100 was so successful and so well regarded, the new ST retains its liquid-cooled 90? V-4 configuration with a longitudinal engine layout for increased efficiency in the drivetrain. With a bore and stroke of 78mm x 66mm, the ST1300 engine is distinctly oversquare, and it churns out an impressive 125 bhp at 8000 rpm, with a brawny torque peak of 85 lb./ft. at 6000 rpm.

A host of upgrades contribute to these improvements. Classic avenues for adding power include better breathing and more compression, and the ST1300 features both. The four-valve DOHC heads now incorporate intake valves measuring 31mm in diameter vs. 27.5mm in the 1100; exhausts are 27mm across compared to the 23mm valves used previously. The ST's accurate shim-under-bucket valve actuation system has been retained, and as a result intervals between valve inspections remain a lengthy 16,000 miles. Compression ratio has been upped from 10.0:1 to 10.8:1, and, like Honda's sportbikes, the ST1300 features aluminum composite cylinder sleeves for better wear resistance and superior heat dissipation compared to conventional cylinder sleeves. A redesigned U-shape radiator has an 8.2-percent-greater capacity for enhanced engine cooling, and a new ring-type fan draws a more concentrated flow of air through the radiator at low speeds to ensure stable operating temperatures for consistent performance and extended engine life.

The crankshaft is a 360 degree configuration, a design that broadens the engine's power delivery characteristics, making the ST1300 extremely tractable. Honda's choice of a shaft final drive adds to the 1300's virtually maintenance-free nature, and a series of dampers on the transmission mainshaft, clutch and the driveshaft reduce noise, vibration and driveline lash--all of which make the big ST a sheer pleasure to ride under all conditions.

To feed this sophisticated mill, Honda's engineers called on the latest, cutting-edge programmed fuel injection (PGM-FI) system to replace the ST100's carburetors. This high-pressure system delivers fuel at 50 psi to four injectors mounted in 36mm throttle bodies. Each injector utilizes 12 laser-drilled nozzle holes to produce an ultra-fine, highly combustible mix of fuel and air to yield the maximum in combustion efficiency and power. This latest-generation Honda PGM-FI system combines a sophisticated throttle sensor plus advanced 3-D digital fuel injection and ignition mapping to produce precisely controlled fuel delivery for smooth, linear throttle response. Also, an auto-enriching system has been integrated into the PGM-FI module to eliminate the need for a manual choke during cold starting. What's more, this new, more powerful engine is even cleaner running than before--clean enough to meet the California Air Resources Board (CARB) emission standards set for the year 2008.

To add a new level of comfort to the ST1300, Honda's engineers incorporated dual engine-counterbalancers to virtually eliminate primary and secondary vibration. This change was also instrumental for enhanced handling; with vibration well controlled, there was no need to rubber mount the engine and it could now be used as a stressed member of the chassis. A host of additional improvements have been made to the engine in the name of handling. For instance, the crankshaft is now located 20mm farther down in the crankcase to lower the center of gravity for improved handling. A new, lighter and narrower silent-type cam chain drive system reduces engine length 10mm, and an all-new cassette-type five-speed gearbox trims off another 40mm. In addition, the alternator has been relocated to the area between the cylinder banks to make the engine even shorter and more compact. As a result, the overall length of the new ST engine is now a full 2 inches shorter than before, even though it is of larger displacement. Lower gearing (5 percent compared to the ST1100) completes the engine package, and gives the ST1300 even stronger acceleration and roll-on performance.

This more compact engine is now cradled in an all-new aluminum frame that is 2.4 pounds lighter than the previous steel frame. Aluminum construction allows engineering to put strength specifically where it's needed in the chassis for optimal rigidity and tuned flex. Triple-box-section spars envelop the engine in a stout diamond configuration, and the massive cast aluminum steering head is evocative of front-line racing machinery. Also in keeping with Honda's latest trends, the solid-mounted engine functions as a stressed member of the chassis-a compact and strong configuration that also saves weight. This arrangement allows the more compact engine to be positioned farther forward than before, and the pilot also sits 1.6 inches farther forward--two changes that help create a pronounced sport-oriented feel and handling. As another chassis upgrade to the ST1300, the new bike now features an aluminum swingarm that's stronger and 1.9 pounds lighter than the ST1100's steel unit.

Look at the ST1300's chassis numbers, and you can see Honda's sporting hand at work. Compared to the ST1100, the 1300's wheelbase is a whopping 2.5 inches shorter and steering rake is much steeper, 26.0 versus 27.3 degrees--two substantial changes that make the new ST remarkably more nimble and agile handling. Up front, the Honda Multi-Action System™ (HMAS™) cartridge fork features massive 45mm fork tubes--larger tubes than the 43mm units used on the race-bred RC51™ and CBR®954RR. In back, the Pro Link® single HMAS gas-charged shock features 1.2 inches of preload adjustability, and strokes through nearly 5 inches of travel. All of which adds up to increased sport capability plus added comfort.

A new Linked Braking System™ (LBS™) ties together the triple-piston calipers of the ST1300's front and rear brakes. The front brake lever now actuates the outer two pistons in the two front calipers and the rear caliper. The brake pedal activates the middle piston in all three calipers, and a delay valve slows initial front brake response to minimize front-end dive. The ST1300 is also available with an optional Antilock Brake System (ABS), which features an electric-motor-driven modulator that gives quick, precise adjustments in braking pressure for smooth ABS action.

Honda engineers worked hard to centralize mass and reduce unsprung weight in the ST1300 for a lighter, more nimble feel. The front brake rotors, for example, are an incredible 4.7 pounds lighter than the ST1100's discs, while a new rear rotor trims off another 10.5 ounces. The front cast aluminum 18-inch wheel is 2.7 pounds lighter and the 17-inch rear wheel shaves off another 9 ounces compared to the 1100. Add in the aforementioned lighter aluminum swingarm, and these changes alone would make the 1300 feel and handle like a new machine. To further help centralize the ST1300's mass without compromising the bike's touring range, Honda engineers gave the new ST a dual-section fuel cell that places 5.5 gallons in the conventional tank location, and another 2.2 gallons in a sub-tank carried low in the chassis. The result is a lowered center of mass, and an enormous capacity of 7.7 gallons of fuel (0.3 gallon more than the ST1100)--for more than 200 miles between the pumps.

With that kind of long-range capacity, it's no wonder Honda equipped the ST1300 with first-class rider and passenger amenities. Start with the ST's striking parabolic lines that foretell slick aerodynamics and excellent wind protection. The fairing flows air both through and around its panels, with air vents in the cockpit area and additional ducting below the windscreen to relieve negative air pressure behind the fairing and virtually eliminate the resultant back-curl of wind. These measures greatly expand the still-air envelope around rider and passenger for an enjoyable degree of comfort.

The windscreen on both models can be manually adjusted over a range of 2.3 inches to accommodate riders of varying heights. In addition, The ST1300 ABS features a new electric-motor-driven windscreen that can be adjusted over a range of 7.4 inches and 13 degrees with the touch of a button, even while underway. Armed with this great new option, riders can crank up the windshield to the optimum position for maximum protection while out on the open road, then lower the screen when approaching a town for increased airflow in the slow going. With all this attention to detail lavished on wind management, it's no surprise to find that even the integrated rear-view mirrors have been strategically located to provide increased hand protection from the wind, especially at high speeds.

To ensure the broadest possible range of seating comfort for riders of all sizes, the ST1300 also features an innovative adjustable seat. This ingenious new three-position design allows the pilot's seat to move over an adjustment range of 1.2 inches vertically and 1.0 inch horizontally. From the lowest, most forward position, the seat can be moved up 0.6 inch and 0.5 inch backward to the middle position, then back and up the same amount to the highest rear position. This range of adjustability, coupled with the upright ergonomics of the forged aluminum handlebars, allows the ST1300 to offer roomy, comfortable seating for serious travelers.

As a final touch for riders dedicated to the long haul, the ST1300 includes secure 35-liter lockable, detachable saddlebags that are large enough to accept a full-face helmet. A host of accessories will be offered to allow ST1300 owners to add even more touring touches as needs arise, with some of the more notable elements being soft Inner Bags to ease packing chores, plus a new large-capacity ST1300-specific Tank Bag with multiple compartments. In the details department, Honda's engineers added a precaution in the form of rugged body-protector stays that will help protect the ST's bodywork in the event of a tip-over. Also, a push button conveniently located on the left side of the fairing allows the rider to actuate an electric motor to adjust the headlight beam as needs and loads change--a thoughtful acknowledgement to real-world riding needs.

Ride hard, ride long. For a select and dedicated group of riders, that's the song of the open road. And with its newfound sport and touring abilities, the 2003 ST1300 sings that song nonstop.

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