Long a purveyor of motorcycles aimed towards a more sophisticated and less frenetic clientele, BMW has undergone a paradigm shift in thinking during the past decade. The company came to the realization that its formerly well-cultivated market share would eventually disappear unless it was replenished—and the only way to do that would be to produce motorcycles that would appeal to the younger generation. How? One sure-fire way is to build high performance motorcycles that can compete head-to-head with the established class leaders, something the company somewhat shied away from in its past. It's been an amazing reawakening for the brand that has a rich racing heritage from the early Grand Prix years, and one that has currently culminated in its return to racing in the World Superbike Championship. BMW is no longer looked at as a maker of sedate motorcycles.
Beefing Up The Top BeemerWhen the K1200S made its debut in '04, it signaled the arrival of BMW to the serious sportbike category. There were no excuses made for this bike; with an all-new 1157cc liquid-cooled, inline four-cylinder engine cranking out a claimed 167 horsepower, the K1200S was no quirky engineering exercise like the company's past four-cylinders. It was aimed squarely at the leaders in the big-bore hypersports category: Suzuki's GSX1300R Hayabusa and Kawasaki's ZX-12R.
Unfortunately, the BMW came up a bit short of its goal. Some initial production problems caused a delay in its release, and then when it was introduced to the international press, there were numerous complaints regarding inconsistent throttle response, balky shifting, and driveline issues. Some post-release fixes helped solve most of those problems, but in the end it still wasn't enough. The BMW was less powerful, not quite as fast, and not as refined as its competition. Nonetheless, the K1200S was close enough for a first attempt that it served notice BMW was not in the class just to make up the numbers.Since that time, however, both the Suzuki and Kawasaki have undergone some major revisions. Actually, the Kawasaki ZX-12R was replaced with an all-new model: the ZX-14 (introduced in '05), powered by a huge 1352cc four-cylinder (the 12R engine was "only" 1198cc) cranking out a true 175 rear wheel horsepower housed in a new twin-spar chassis. Meanwhile, the Hayabusa underwent a thorough revamp last year, including an engine displacement boost from 1299cc to 1340cc, allowing it match the Kawasaki in peak power and retain its torque advantage.
With Kawasaki and Suzuki upping the ante in the big-bore hypersports class, it was left to BMW whether to match the competition's bets, or to fall back on its old ways of creating its own market niche. The management decided the latter wasn't acceptable, and tasked BMW engineers with boosting the K-bike's performance.The engine received a 136cc displacement increase (for a total displacement of 1293cc), care of 1mm larger bore (now 80mm) and a whopping 5.3mm-longer stroke (now measuring 64.3mm). Despite the larger bore, each piston is 12 grams lighter due to its slipper skirt design plus thinner compression and oil control rings. The cylinder head intake ports now feature internal edges to help promote swirl in the combustion chamber, and revised exhaust cam timing to work with the displacement increase. The airbox, filter, and intake ducts have been redesigned with the larger engine in mind as well, with revised engine mapping aimed at improving partial throttle performance. Dual throttle cables (one for open, one for close) and a new all-metal idle control valve complete the engine changes.The previous ballistic-missile-size exhaust muffler is gone, replaced with a shorter unit that features an integrated catalyzer to help meet the strict emissions standards of both Europe and the USA. Also new is an integral exhaust valve to control back pressure throughout the rpm range for better power and torque in the lower portion of the powerband. All told, the changes result in a claimed peak power figure of 175 horsepower at 9250 rpm, but the bigger news is a major increase in torque to 103 ft/lb, with a claimed seven-ft/lb increase from 2000 to 8000 rpm.
The hydraulically-actuated clutch now features a larger slave cylinder for easier lever effort, with new friction plates, springs, and stronger spring plate to handle the increased torque. Gearbox action was also attended to, with a revised pivot point for the shifter, shifter rod now running in ball bearings, and new 3-contact-point shift forks (versus the older two-point) for easier shifting, and undercut gear engagement dogs with greater engagement surface for more positive gearchanges. The driveshaft now features a two-stage damper system; the first stage handles small torque changes with a spring-loaded friction disc, while bigger load variations are handled by polyurethane bushings encased in the rubber damper portion of the driveshaft system.In an effort to improve front-end feedback from the Duolever front suspension, the geometry of the A-arms and "wheel carrier" (basically what comprises the fork in a conventional telescopic fork) has been changed. The lower control arm is now made of aluminum, saving 2.2 pounds of unsprung weight, and the spring/damping rates are now firmer overall. A second-generation version of BMW's Electronic Suspension Adjustment (ESA II) that now alters spring rate as well as preload and damping is available as a $900 option (more on that later).
The BMW ABS system is now standard with the K1300S, and it can be shut off if desired. It has also thankfully jettisoned the servo-assist system used with the K1200S that made modulation and feedback poor at slower speeds. A no-cost option is a 1.1-inch-lower seat that drops the seat height to 31.1 inches, allowing more riders to fit the K1300S (this is an option that will be available through much of the BMW range for '09).BMW has also debuted an ASC (Anti-Spin Control) traction control system on the K1300S as a $400 option. Because the BMW already has wheel speed sensors as part of the ABS, it was a relatively simple matter to fit up a traction control system. There are the usual host of other options available, from heated grips to a GSA (Gear Shift Assist) powershifter. BMW will also be offering two additional "special package" models with various options included. Besides the $15,250 base model, there is the "Standard Package" with heated grips that runs an additional $250, and the $17,500 "Premium Package" that includes the GSA, ESA II, heated grips, tire pressure monitoring system, and ASC.
One last change to the K1300S that will also soon be standard issue with all BMWs: after decades of saying "we'll do it our way," BMW will now be joining the rest of the world (other than the lone exception of Harley-Davidson) in adopting the single-button turn signal actuator. Hallelujah!Unleash The Hounds!BMW let the American moto-press sample the new K1300S in the mountains above Santa Barbara, California, an environment rich with twisty roads upon which to test out the upgrades instilled into the latest Beemer. The unit we rode was a Premium Package model, so we were able to test the complete BMW acronym soup of ESA II, ASC and GSA.Immediately noticeable is the increased grunt of the new engine. You can literally let the BMW chug down to 1500 rpm in top gear, twist the throttle to the stop, and get nothing but smooth acceleration (the twin counterbalancers quell vibes well) that rapidly builds in ferocity. There's excellent power on tap as low as 4000 rpm, enabling you to run a gear higher in many situations that would tax the previous powerplant. Highway overtaking is now accomplished with ease and quickness.However, it's the boost in midrange and top-end that will really get your attention. While the K1200S couldn't exactly be labeled a weakling, even when compared against the old Hayabusa or ZX-12R, it just didn't have the same hair-on-fire, peel-your-face-back acceleration at higher speeds (and when compared against the latest Hayabusa or ZX-14 it paled even more). Now when you grab a handful of throttle, the acceleration has that same unrelenting locomotive-on-nitrous feel that continues well into triple digit territory. And yet the powerband is much more linear as well; there's none of the power spikes at 6500 and 8000 rpm that the old engine had.
Throttle response—especially off trailing throttle entering a corner—is silky smooth, with none of the jerkiness that plagued its predecessor, allowing earlier and stronger drives off corners. There was one small hiccup, however: on trailing throttle between 5000-5500 rpm, there was a distinct flat-spot/hesitation when you got back on the gas. It was much worse in the higher gears, mostly because it was easier for the engine to pull out of it in the lower cogs. It definitely felt like a lean fueling issue, and while not alarming, it became bothersome when running through a series of medium speed corners where you often end up accelerating from that rpm.The traction control is non-adjustable, and as such, its interrupt strength and threshold are both fairly conservative. While not overly obtrusive (unless you try to pull a wheelie, which it swiftly kills off in midstride, resulting in the front end slamming back to earth), you can definitely feel its electronic hand slowing you down when you start trying to push the limits of the OE fitment ContiSport Attack rubber. Like the ABS, it can be turned off if so desired.
The second-generation ESA II differs from the previous version by its ability to not only adjust spring preload and damping on the fly, but also spring rate if required. By using a movable internal sleeve that adjusts how much support is given to an elastogran (a thermoplastic polyurethane elastomer) sleeve at the end of the spring, the system in a roundabout way adjusts the spring length, thereby changing spring rate. We actually grew to like the first ESA system on the K1200S, and the same is true of the ESA II on the K1300S; it's undeniably convenient to be able to switch the suspension from twisty road firm to highway plush at the push of a button. We ran the setting on standard with a single rider when corner carving, as the sport settings were too firm in our opinion.
A powershifter is a nice idea on a bike that requires a lot of shifting like a high-strung 600, but on a torquey, wide-powerband beast like the K1300S, the GSA is kind of overkill. We also found the unit's delay time to be too long, with the shifts often taking longer than a crisp non-clutch upshift would.
source:http://www.sportrider.com