BMW HP2 Sport

ONCE A BASTION OF TWO-WHEEL CONSERVATISM KNOWN PRIMARILY for sensible, durable touring bikes with superior saddlebags and high technology, BMW has done something strange: It's added plastic sliders to the cylinder heads of its latest, most performance-oriented bike ever. Further, those plastic, replaceable inserts are mounted in carbon-fiber valve covers. Crazy times, yes. but, get this: those covers enclose dual overhead cams. And there wasn't a saddlebag to be found at the recent BMW HP2 Sport press launch.
Yes, in terms of the old BMW image, the Germans have taken a calculated step off the deep end and are learning to build bikes that shred. The low-volume High Performance line of machines is but a piece of a larger overall scheme to change the company's image to that of a modern, sporty, forward-thinking motorcycle producer.
The HP2 Sport is the latest in the line of HP bikes, and is by far the sportiest Boxer ever.
You have seen this very bike during development on the world endurance roadracing championship circuit, because that is where BMW chose to develop it. And the production bike we rode at Race Resort Ascari in southern Spain is hardly removed from the raccbikc that Associate Editor Conner rode at Magny Cours (sec sidebar). Aside from quick-change wheels and a fancy tailpipe, down to the cam grind these bikes are essentially the same.



In fact, BMW is so serious about the "Sport" part of this bike's name, we didn't ride Mile One on the street. It was all deep lean angles, hard braking and wringing out this surprisingly throaty 130-horsepower flat-Twin on a closed course.
Although the Sport is based on the previous BMW R1200S, it is quite a departure from that machine. Foremost, of course, is the addition of the four-valve, dohc heads. This all-new design has CNC-millcd intake ports (things of beauty...) and radially disposed valves for a very compact combustion chamber. It must be a good combustion chamber, because compression is a very high 12.5:1 and there is only one sparkplug per head-past R-model, single-in-head-cam-with-pushrod engines used two plugs per hole in the wide, 101mm bores, and lower compression. In the unabashed pursuit of big power, valve sizes were increased quite a lot, with the intakes up 3mm to 39, and exhaust sizes bumped 2mm to 33. The large sizes were made possible by the radial setup. I [cat management is critical in this air/oii-cooled engine, so the heads feature internal oil passages around the nitrided valves. (Surface hardening via nitriding is preferred on slim components such as valves and crankshafts because the heating and cooling processes are slow and controlled; there is no shock cooling as with "quenching" a part in other types of hardening.) Again for cooling, the exhaust valves are sodium-filled for better heat transfer up the valve stem and into the heads themselves, through the guides.



The valve-actuating finger followers (with shim adjustment clearance checks at 6000-mile intervals) are like those used on the K1200 engines. In terms of aftermarket "hard" tuning, the conically ground cams-to accommodate the radial valve stems-are a bit of a roadblock to changing profiles (who will grind them ?!) and timing, and because each cam controls an intake and an exhaust valve. Changing timing on one cam. as you can on a conventional one cam for intake and one for exhaust setup, may not have the desired results!
In the past, BMW has cited bulkiness as a reason for not employing overhead cams on its Boxers. But the engineers in this case managed to make the heads more compact to the tune of 10mm each.

Ghost bodywork reveals minimal steel-tube rear frame attached to the stressed-member engine. Tailsection is structural carbon-fiber that saves 4.5 pounds over conventional construction. Front Teielever A-arm is designed to break away in a serious crash to save the engine cases from damage. All-new dohc heads sit atop beefed-up cylinders. Compression is an ultra-high 12.5:1, all the more impressive in tight of the 101mm bore and single sparkplug per cylinder.
Said overall R-model chief Franz Bergman, 'i must admit we were surprised that it was possible to do that, but our engine designers were obsessive about their work."
Mahle forged pistons have a low-friction coating on their "miniskirts," while abbreviated wristpins ride in bores that are gusseted to those little skirts for strength. Con-rods are new, too. The cylinders and crankcase have also been modified. The four cylinder/head bolts arc spread out wider, which made it necessary to change the location of the oil galleries. But it also made it possible to increase cylinder wall thickness, up from 2.1 mm to 4.2. This all provides for less distortion in light of the increased revs and power output this new engine is capable of.

This is by far the quickest-revving, hardest-pulling Boxer engine I've ever tried. There is a lot of snap, and while bottom end torque is pretty good (claimed 85 ft.-lb. at 6000 rpm), dividends are paid by keeping the engine speed up closer to the 9500-rpm redline.
This is pretty easy with the close-ratio six-speed gearbox, equipped from the factory with a quick-shifter, no less. First- and second-gear ratios are taller to reduce the rpm drop between shifts and to make first more useful as a "real" gear, rather than the one you use to get started on a hill with fully loaded saddlebags. The quick-shifter cuts both fuel and retards ignition to allow fuli-throttlc clutchlcss upshifts, and an accessory sensor allows the pattern to be altered from the conventional one-down, five-up street norm to the one-up, five-down racer setup. In practice, the system worked well on high-rpm shifts. But short-shifting between corners caused rough gearchanges that, coupled with the torque effect of the longitudinal crank, upset the chassis a bit. Best to use the clutch in that case.

It's also good to use the clutch with some care on downshifts. There is considerable engine braking at work from this 1170cc air/oil-cooled Twin, and corner entrances could be made quite interesting with wheel hop if you are careless on downshifts; there is no slipper clutch.
This was about the only upset we found in the chassis after a day of railing around Ascari. The fully adjustable Ohlins shocks front and rear were set up nicely. In fact, it wasn't too long before those fancy carbon-fiber valve covers and their integrated sliders were kissing the pavement in a few corners. When lunch came, the request was put in to raise the front ride height to 12.5mm (of 23mm), with the rear set at its max height of 30mm, This both improved front-end feci and stopped the cylinder-head covers from touching down. Lean as far as you want! We also tightened up damping, which really planted the bike in fast sweepers.

Lap times and peak speed increased in the afternoon session, too. How do I know? The 2D electronic dash has lap and data functions including maximum and minimum speed, percentage the throttle is open per lap, percentage of the lap you spent braking, best lap, current lap, etc. In "race" mode, the speedometer is minimized and the gear-position indicator is enlarged. Shift-light intensity is adjustable and the green-yellow-red progression means shifts can be timed perfectly. There are a lot of ways to parse the data to your liking and it is highly motivating to try to beat your own best time.

In fact, there really isn't much going on here to stand in the way of charging really hard on the track. Turn-in response is pretty good, if not quite up to lOOOcc Japanese sportbike or Ducati 1098 levels. But the lightweight forged-aluminum wheels (with a wide 190/55ZR17 rear on a 6-inch rim) and a comparatively light claimed weight of 392 pounds help with agility, as do the 24-degree rake and short, 3.4-inch trail, even if the 58.4-inch wheclbase is on the long side.
After a succession of hard laps, the lever on the Magura radial brake master cylinder started to exhibit more travel, although the Brembo Monobloc calipers always did their duty. Compensation for the travel was made easy by the lever reach adjustment. Our testbike was fitted with non-ABS brakes, although ABS is available as an option. And, as it was on the so-equipped R1200S, the anti-lock can be switched off for track use.

I looked the bike over more and more and noticed the adjustable handlebars, machincd-from-billct top triple-clamp, adjustable billet footpegs and all the other fine, highly finished pieces on the bike. The fairing and tailseclion arc self-supporting carbon-fiber structures, made of pre-preg, autoclave-processed pieces. Even the stainless-steel exhaust system (with computer-controlled valve and catalysts) showed a level of design and finish that is a step well above average. I asked the HP2 Sport's powcrplant engineer, Rudi Schneider, about this. "This project was different for us," he said. "We worked together, but we also are friends, we ride together and it was special for us to work on this project. I think it shows in what we have produced."I also wondered how a project like this got started: "We just got some crazy engineers together to talk about what we could do and said to our managers, let's build a bike like what the HP2 Sport turned out to be." What it turned out to be is a Boxer that rocks. Keep those crazy engineers talking to each other!.