Then & Now: BMW HP2 Sport vs. R90S

Teutonic twins

By John L. Stein, Photography by Kevin Wing

Google up an early-'70s photo of Brigitte Bardot, and surely there was no more beautiful creature on earth. But fast forward a few decades and you've got a 76-year-old broad. Time isn't kind to anyone, and sometimes the pursuit of physical perfection is better left to youth. Unless we're talking motorcycles, of course: Because as the righteous know, few experiences compare with rushing a superbike of any age along a curvy road, banking through the corners and feeling your arm ligaments stretch taut as you turn on the gas.

But like today's homey fashions, some of the current über-rides aren't exactly easy on the eyes. Fouled with radiators, wiring and sensors, hoses, scoops and vents, they are technologically amazing but lack the mechanical purity of their forebears. An old engineering parable holds that what looks right is right. And since the original superbikes looked so absolutely and consummately right, we wanted to learn just how far the current species has really come since then.

To do so, we assembled one classic '70s superbikes from each of the five great motorcycle-producing nations-America, England, Germany, Italy and Japan-along with a sparkling new derivative of each. Our mission was to draw as straight a line as possible from old to new, because the original superbikes were actually today's naked bikes. Most lacked fairings and offered sit-up riding positions, and some worked better as tourers or commuters than hairpin straighteners. But still, they were the beginnings of superbikes as we know them today.

The 1976 BMW R90S Boxer's logicial descendent is the sporty HP2 Sport. For the '73 Ducati 750 GT, it's the versatile two-valve, air-cooled GT1000. In Harley-land, the iconic '77 XLCR Cafe Racer hands off to the XR1200. The Kawasaki choice was as easy as slam-dunking on the kids' court, with the original '73 Z1 greeting the all-new Z1000. And from Triumph comes the final '76 T160 Trident triple and the current Speed Triple hooligan bike.

Some readers may cry foul upon realizing there are no Hondas, Suzukis or Yamahas here, but this is no accident. Honda's game-changing 1969-'75 CB750 Four has no modern naked-bike equivalent on our shores. Suzuki's period liquid-cooled GT750 triple was more of a tourer, and a two-stroke at that. And Yamaha's RD400 and TX650 twins technically weren't even superbikes-although the two-stroke RD certainly beat its share of them.

The five modern bikes and their predecessors-kindly loaned by Motorcyclist readers-met at Willow Springs Raceway's Horse Thief Mile road course on a sunny April morning to go where no home-decorating magazine has gone before: Back to the Present. The five individual vignettes that follow give all the dirty secrets we discovered in our back-to-back rides on the racetrack and a two-lane desert loop. Without revealing too much detail in this introduction, we can unanimously tell you this: Buy an old bike to polish and a new one to ride. You'll be glad you did.

Teutonic Twins
In 1974, it would have been hard to find a more stoic motorcycle company than BMW, the builder of dependable but uninspiring Boxer twins. But when the R90S launched, it didn't just fight its way upstream; it jumped in at the top. Its bikini fairing with integrated instruments, sensational smoke-gray custom paint, huge pumper carbs and heightened state of tune served notice that this was not Uncle Wilhelm's old Bay Em Vay. West Coast distributor Butler & Smith backed it up by fielding race-prepped versions for Reg Pridmore, Gary Fisher and Steve McLaughlin at the inaugural Daytona Superbike race in '76, which McLaughlin won in a photo finish. The R90S also earned that year's first AMA Superbike Championship for Pridmore.

"The best part was, if you can imagine this, a twin-cylinder airplane motor beat the Japanese best," McLaughlin laughs 34 years later. "The R90S was lighter to throw around than a Z1, but overall there was nothing that great about it. It wandered on the straightaways, and the disc brakes used a cable-operated master cylinder and single-piston calipers. At Daytona, where you need brakes, we said, 'You have to fix these.' They said, 'No, this is the right way.' So rider talent is really what put those bikes on top."

Infrared systems engineer Eric Schulte has owned this '76 example for 15 years. Like BMWs then and now, the R90S is definitely a different cup of tea, and it probably took more than tea to inspire the Butler & Smith crew to forge it into a Superbike winner. Big cylinders sticking into the wind, copious suspension travel and BMW's characteristic torque pulsing and roll moment all reinforce the quirkiness of the brand.

Riding an old-school BMW Boxer requires fine throttle control due to the suspension jacking that punishes a ham-fisted technique, though BMW eventually addressed this with its Paralever rear suspension. The Germans also had yet to master gearbox civility, thus sometimes the R90S goes into gear silently while other times there's a bone-crunching crack!

With a modest upward lurch, the R90S is underway. As the speedometer needle climbs, the bike comes into its element as a high-speed autobahn burner. The faster it goes, the more comfortable it seems, and at cruising speed it's quietly whooshing along, glass-smooth, with all systems green. The tall 32.2-inch seat height, low footpegs and modest handlebar rise give the R90S the roomiest cockpit of this group, and while this doesn't necessarily make it a great sportbike, it sure adds comfort on long riding days.

Whereas the R90S was all about long-distance comfort, the current HP2 Sport is a hard-core sportbike. Easily the most expensive machine in our group, the HP2 is also the pinnacle of Boxer sportbike development to date. Glistening with carbon-fiber parts and featuring a versatile racing-style LCD dash, the HP2 can help you monitor lap times, while shift-warning diodes and a clutchless quick-shifter add to enjoyment on the track.

And that's just where the HP2 Sport belongs-on the track, or at least a fast, winding mountain road. Its low handlebars require a long reach and demand submission from the rider-exactly the opposite of the old R90S. The HP2 motor is revvy and makes good low-end and midrange torque together with a satisfying blast at the top end-similar to the Triumph Speed Triple but with a decidedly different exhaust note. It's deceptively quick as well, gunning down the quarter-mile in 10.5 seconds at nearly 133 mph-quicker than even the new Kawasaki Z1000.

Thanks to its modern Paralever rear suspension, the HP2 doesn't rise significantly when accelerating, though there still is some shaft-drive effect. Even better, its suspension doesn't let the machine drop down on its haunches when you back off the gas, meaning that you won't suddenly find a cylinder head grinding the pavement. Likewise, the front Telelever suspension limits dive even under extreme braking, making the BMW one of the most stable and predictable of this group dynamically. That's a monumental difference from the original.

The fuel-injection mapping is problematic at partial throttle, which is annoying when you're trying to delicately roll into the power while apexing a turn. Unfortunately, the critical control you need right off idle is simply not there, so instead you go from no power to a little burp of power too suddenly. Between this glitch and the hard-on-the-wrists riding position, the HP2 moves substantially away from being a satisfying daily rider or sport-tourer, as was the R90S's forte.

But oh, how it looks! What BMW has managed to design around the oddball Boxer engine is nothing short of miraculous. Well balanced, insightful and intelligently detailed, it's no wonder the HP2 Sport represents the promised land for Boxer performance devotees.

Call this pair the odd couple: The R90S loves the open road, the HP2 Sport lives for the track.

THEN & NOW 1976 BMW R90S 2010 BMW HP2 SPORT
Price new $3430 $26,500
Dry weight 474 lbs. 433 lbs.
Horsepower 67.0 bhp @ 7000 rpm 118.0 bhp @ 8750 rpm
1/4-mile 13.1 sec. @ 102.0 mph 10.50 sec. @ 132.5 mph
Tire size 3.25-19 front, 4.00-18 rear 120/70-17 front, 190/55-17 rear
Brakes Dual disc front, drum rear Triple discs
Wheelbase 57.7 in. 58.5 in.

Dyno
The HP2's 118 horsepower make it the second-strongest bike here, but you'd never guess that riding it. Most of that power is focused near the top end and it takes a lot of buzzy revs to access it. Excessive driveshaft jacking and the inertial force of the longitudinal crankshaft are distracting.

Ergos
As usual, BMW hits a home run in terms of ergonomics. Everything is adjustable, but there was no need to fiddle; the HP2 felt plenty comfortable as delivered. The only drawback is the rearview. Those mirrors shake and wiggle so badly that looking over your shoulder is the only viable option.

BMW HP2 Sport | Price $26,500
Tech Spec
Engine type: a/o-c opposed-twin Frame: Steel trellis with single-sidedaluminum swingarm Rake/trail: 24.0º/3.4 in
Valve train: DOHC, 8v Front suspension: Telelever featuring Öhlins shock with adjustable spring preload, high/low-speed compression and rebound damping Seat height: 32.7 in.
Displacement: 1170cc Rear suspension: Paralever featuring Öhlins shock with adjustable spring preload, high/low-speed compression and rebound damping Wheelbase: 58.5 in.
Bore x stroke: 101.0 x 73.0mm Front brake: Dual Brembo four-piston calipers, 320mm discs with ABS Fuel capacity: 4.2 gal.
Compression: 12.5:1 Rear brake: Brembo single-piston caliper, 245mm disc with ABS Weight (tank full/empty): 458/433 lbs.
Fuel system: EFI Front tire: 120/70ZR-17 Metzeler Sportec M3 Colors: Alpine White
Clutch: Dry, single plate Rear tire: 190/55ZR-17 Metzeler Sportec M3 Availability: Now
Transmission: 6-speed Warranty: 36 mo., 36,000 mi.
Measured horsepower:118.0 bhp @ 8750 rpm Contact:www.bmwmotorcycles.com
Measured torque: 77.9 lb.-ft. @ 7250 rpm
Corrected 1/4-mile: 10.50 sec. @ 132.5 mph
Top-gear roll-on:3.24 sec.
Fuel mileage (high/low/avg.): 51/33/42 mpg
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By John L. Stein
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