Buell 1125R: The no-excuses V-twin sportbike from the U.S. of A.

Photo by Kevin Wing

By Lance Oliver

In the sportbike world, a Buell has always been the quirky choice.

Over the years, Buell engineers have massaged the Harley-Davidson Sportster engine beyond recognition, refining it and extracting more power. They came up with innovative solutions to vibration and cooling issues. Then, with the XB line, they made their motorcycles even more unique by putting the fuel in the frame, the oil in the swingarm and making the wheelbase ultra-stubby.

And lots of people wondered, This is interesting stuff, but when is Buell going to build a sportbike with a more powerful liquid-cooled engine?

The answer is now, and the motorcycle is the Buell 1125R.

"It's been a long time coming," said Paul James, director of product communications for Buell and Harley-Davidson.

Development of the 1125R began four years ago. When Buell, now a wholly owned subsidiary of Harley, got the go-ahead to look outside the company for a new powerplant, several manufacturers were considered. But the choice quickly narrowed to BRP-Rotax. The Austrian company has built motorcycle engines for Aprilia and BMW, as well as engines for personal watercraft, snowmobiles, and other vehicles.

More importantly, said Erik Buell, the Austrian company was willing to work with Buell to develop a new engine from scratch for the 1125R. The fit felt right, he said. In fact, one of Rotax's lead engineers in Austria on the Buell project had worked at Buell as a college intern.

Buell set parameters for power output and weight (but not displacement) and Rotax designed an engine to meet the goals. The result is the Helicon engine, a 72-degree V-twin (unlike the 60-degree twin Rotax built for the Aprilia Mille or the 90-degree twins found in Ducatis). Buell engineers wanted the angle of the V to be as narrow as possible, to allow more flexibility for positioning in the frame, but wide enough to allow a straight shot from the throttle bodies into the combustion chamber, and 72 degrees turned out to be the magic number.

The fuel injection system uses two huge, 61mm throttle bodies. Buell made the four valves per cylinder as large as possible, even using the smallest available spark plug to take up less space. The engine is solidly mounted in the frame, so three balancers are used to control vibration.

Buell claims output of 146 horsepower at 10,500 rpm, measured at the crank, and 82 foot-pounds of torque.

The Helicon engine is a dry-sump unit, but Rotax grafted an oil tank onto the left side of the engine, so although the swingarm retains a family resemblance to the XB line, it does not do double duty as an oil tank.

Similarly, the 1125R's frame resembles the XBs', and still holds the fuel, but it's all new. Fuel capacity is increased to 5.6 gallons and ducts in the frame divert hot air that has passed through the side-mounted radiators into the engine area and away from the rider.

Also worth a mention on the Helicon engine is the clutch, which uses engine vacuum to reduce clutch pull effort and to provide some back-torque-limiting effect. You can feel the effect by pulling the clutch lever with the engine off, then pulling it again with the engine idling. Similarly, closed-throttle deceleration creates engine vacuum that reduces the clutch clamp load. It's an entirely different approach than your typical, mechanical slipper clutch, but Buell engineers say it has the advantage of using a free power source: the engine vacuum.

Buell gave us the chance to try the bike on a two-day ride, on the street and on the track at Mazda Raceway Laguna Seca. Unfortunately, due to a particularly poorly timed case of food poisoning, I missed virtually all of the street ride.

The first thing that's obvious when I sit on the Buell is that the ergonomics are more relaxed than most sportbikes today. Leg room is ample, and the handgrips are not punishingly low.

"This is first and foremost a streetbike," said James, and before anyone starts crafting crazy plans about a Buell team in AMA Superbike, consider that planning for the 1125R began two years before talk of allowing 1,200cc twins into that class. The 1125R was not designed to be a platform for a Superbike race effort.

Fire the engine, and the sensation is both welcome change and reassuring familiarity. Gone is the over-caffeinated vibration of the air-cooled, 45-degree V-twin at idle in the other Buells. But this still feels like a V-twin. Still feels like a Buell. It's a little more raucous in feel than the humming four-cylinders in the sporting class.

The motorcycles used for the press introduction were pre-production models, and some details were still being determined. For example, on the first day, several riders found the 1125R had an unsettling habit of taking a long time to return to idle rpm when the throttle was closed, leading to much less engine braking than expected entering a turn. Buell engineers recalibrated the fuel injection overnight and the problem was gone the second day.

Similarly, some of the motorcycles were running at high temperatures, and Buell said the cooling system settings were another detail still being fine-tuned.

Engine heat roasting the rider is a common complaint on today's high-powered streetbikes, but the Buell's side-mounted radiators and in-frame vents keep the heat away from the rider's legs and upper body. On the other hand, some riders' right feet were roasted during the street ride by the underslung muffler, which is right next to the footpeg. And while the gear shift and rear brake levers have a nice feature, in the form of adjustable toe pegs to fit your particular boot size, you might not want to touch them with your bare hand at the end of a long ride. They get hot.

Riding the motorcycle at Laguna Seca, such minor issues disappeared. What appeared in their place was a broad plateau of a torque curve. Holders of AMA professional roadracing licenses will probably get around a roadrace course faster on a Suzuki GSX-R1000, but I predict most riders would be able to ride the Buell more quickly and more confidently on the track, and will find the power more accessible on the street. Miss a gear shift? No problem. The Buell just powers out of the corner, even if you're a gear off, and pulls all the way to the 10,500 rpm redline.

If you are in the wrong gear, you won't be able to blame the bike. The 1125R's six-speed transmission shifts as slickly and predictably as any I've sampled.

At the top of the rpm range, the rider feels plenty of tingles coming through the footpegs, but other than that, the three balancers keep the engine smooth while still letting it feel like a twin. A few times, I glanced at the tachometer and was surprised to see the engine was revving nearly 2,000 rpm faster than I thought.

Brakes? Got 'em in quantity. The 1125R uses the single rim-mounted rotor you've seen before. This one is clamped by the eight-piston caliper made by Nissin that's found on the XBRR race bike. The front brake lever is adjustable, like the clutch lever. The rear brake caliper is mounted directly on the swingarm for simplicity and weight savings.

And, unlike some earlier Buells, the 1125R does not stand up under braking. Go ahead. Trail brake all you like.

If you do, not only will the brakes not get in your way, but the sturdy chassis, the 47mm inverted fork and the Showa rear shock will handle whatever comes along. The 1125R is stable under braking and predictable in the corners.

Entering a corner, the effect of Buell's version of a back-torque-limiting clutch is not as pronounced as the other mechanical versions I've ridden. You can get clumsy with the downshifts and throttle and cause rear wheel hop, but the margin is wider than with a regular clutch.

And in case you're wondering how those side-mounted radiators hold up in a crash, two of the Buells went down in the two lowest-speed curves at Laguna Seca. The plastic pieces covering the radiators, hoses, coolant overflow bottle and electronics were scratched and broken, but no other parts were damaged. Both bikes were ridden back to the pits. An aluminum bracket behind the plastic pods acts like a leaf spring, absorbing some of the impact and limiting damage in a tip-over.

While it's still a long way from Japanese four-cylinder or Italian V-twin orthodoxy in the sportbike world, the 1125R provides the stiffest competition yet in a U.S.-built, mass-production sportbike.

"We believe this motorcycle will bring people across the threshold of a Harley-Davidson/Buell dealer who have never been in the dealership before," said James.

Erik Buell (see related interview) describes the target customer as an experienced rider who wants a sportbike capable not only of short bursts in the canyons and the occasional track day, but also all-day rides, a sophisticated buyer who appreciates a broad spread of power more than a high-rpm hit that's hard to use on the street.

"He's not looking for the girly giggle of the guy who's buying his first high-performance bike," said Erik Buell of the 1125R buyer he has in mind. "He's not looking to scare himself."

For its first model year, the Buell comes only in Midnight black with Diamond blue frame, swingarm and wheels. The dark blue, with a metallic sparkle in the sunlight, contrasts attractively with the gloss black.

Production has not yet begun, but Buell dealers should get at least one 1125R each by the end of the year, the company says.

In today's sportbike market, where 1,000cc fours, 1,200cc twins and 600cc fours are all platforms for Superbike and Supersport racing efforts, the Buell 1125R is still a distinctive choice. It's just no longer a quirky choice.