Buell 1125R: The no-excuses V-twin sportbike from the U.S. of A.
By Lance Oliver
n 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.
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.
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.
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.
Engine Liquid-cooled V-twin, four valves/cylinder
Bore x stroke 103mm x 67.5mm
Carburetion Electronic fuel injection, dual 61mm throttle bodies.
Compression ratio 12.3:1
Final drive Goodyear aramid-reinforced belt
Tires 120/70-ZR17 front; 180/55-ZR17 rear
Front brake Single 375mm floating rotor, 8-piston caliper
Rear brake Single 240mm fixed rotor, two-piston caliper
Front suspension 47mm Showa inverted fork, adjustable compression and rebound damping and preload; 4.72 inches of travel
Rear suspension Showa monoshock with external reservoir, adjustable compression and rebound damping and preload; 5 inches of travel
Seat height 30.5 inches
Lean angle 48 degrees, soft contact; 50 degrees, hard contact
Rake /Trail 21 degrees/3.3 inches
Wheelbase 54.6 inches
Fuel capacity 5.6 gallons
Dry weight 421 pounds with fluids minus fuel