Cycle News

2015 BMW S1000RR FIRST RIDE P82 settings are preserved, ready for the next time you fancy another session in pursuit of electronic perfection. The Pro package also includes DDC semi-active electronic sus- pension as featured on the HP4, as well as heated grips, launch control, a pit lane speed limiter program complete with the stac- cato soundtrack of World Super- bike or MotoGP, LED indicators, a wide-open powershifter and, for the first time ever on a customer street bike, an optional GP/WS- BK-style auto-blipper downshifter system. This means you need never use the clutch lever again after setting off from rest. And if that race-derived feature isn't suf- ficient, from the other end of the motorcycling spectrum there's an optional gizmo straight out of the touring segment—cruise control. Yes, folks, you can ride your Su- perbike-with-lights to your cho- sen track day at strictly street- legal speeds along boring dual freeways festooned with speed cameras, as well as making sure your fingers are kept nicely warm on a cool spring or autumn ses- sion via those heated grips. And to make sure you stay upright on track to be able to ride it home again there's another option in the form of switchable 15-stage DTC traction control, with seven settings either side of the de- >>TECHNICALLY SPEAKING In creating the heavily improved 2015 version of its class-leading S1000RR, the German manufacturer's engineers have built on the basis provided by the now-discontinued limited-edition HP4 high-performance spinoff version which debuted in 2012. Discontinued, because the new S1000RR now incorporates every- thing that made the HP4 stand out from the stock model—and then some. The S1000RR's very compact (just 463mm wide at the crank) water- cooled four-cylinder in-line motor, measuring 80 x 49.7mm for a capacity of 999cc, is still for the time being at least the shortest-stroke four in the one-liter marketplace. It's even more extreme than the 78 x 52.3mm reigning World Superbike Cham- pion Aprilia RSV4. Originally derived from BMW's Formula 1 engine, the RR motor's DOHC 16-valve cylinder head features small, light, finger-cam followers rather than more traditional bucket-and-shim tappets to operate the paired titanium valves. At 33.5mm intake and 27.2mm exhaust, these re- main the largest and deepest-breath- ing of any one-liter Superbike four (thanks to the S1000RR's wide bore diameter) and are set at a flat-included angle of 24.5°. This results in almost a 50% reduction in reciprocating mass, says BMW. Combined with the short stroke, it offers the potential for higher revs and aggressive cam profiles, as well as more precise valve timing. But with the aim of further improv- ing power and torque while combin- ing this with enhanced rideability, BMW has reworked the cylinder-head porting on the new bike, while fitting slightly lighter (two grams each) inlet valves, each carrying dual springs, while the exhaust valves have a single spring apiece. They're operated via camshafts driven up the right side of the engine by a chain, operated by an idler gear running directly off the conventional-throw 180-degree crankshaft; a modular camdrive format shared with the Aprilia RSV4 helps keep the engine compact. A new inlet camshaft is now fitted with a fuller contour for more dwell, but the forged one-piece steel crank is unchanged, while the Nikasil-bore cylinders remain inclined forward at 32° in the slant- block motor. This helps produce a compact package that's just 558mm high, delivering a low center of gravity. Compression ratio is now 13:1, and both the Eaton water pump and oil pump are chain-driven off the gearbox driveshaft. Further modifications to the new BMW's intake system include shorter length intake tracts aimed at enhancing midrange power, a 0.2-liter larger air- box, and a full RBW/ride-by-wire digital throttle working directly off the twistgrip. It no longer employs a cable to operate the remote RBW sender unit. The unchanged 48mm Dell'Orto throttle bodies breathe through the now 8.1-liter airbox ram-fed from the central intake duct running either side of the steering head at up to 30 bar pressure at 250kph—good for a more than 5bhp power boost at that speed, says BMW. They each retain twin injectors—one top-mounted, the other below the single butterfly, which is controlled by the rider via the RBW throttle. The S1000RR still features a variable-length intake system, comprising four plastic trumpets each divided into an upper and a lower section. These remain connected to optimize drive at lower revs, until BMW's own BMS-X engine manage- ment ECU—which monitors engine rpm and the degree of throttle open- ing via a potentiometer—sees engine revs hit the chosen 11,500 rpm mark (down from 12,000 rpm before). It then activates an electric servo motor to separate the two parts of each fun- nel, leaving the bottom halves in place to function by themselves as velocity

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