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2008 Buell 1125R

2008 Buell 1125R

Liquid-cooled Buell 1125R Redefines The Sportbike Riding Experience

The Buell Motorcycle Company is set to break the conventions of the sportbike category with the Buell® 1125R, an all-new, large capacity sport motorcycle that delivers a sublime balance of street and track performance. Rooted in the core design principles and character that have defined Buell motorcycles for 25 years, the 1125R offers power, torque, handling and agility that will take its owner to a new level of riding experience.

The Buell 1125R boasts a carefully balanced combination of engine performance, precise and agile handling, advanced aerodynamics, and superior rider environment and control, all packaged with distinctive styling leaving many of the motorcycle’s mechanical components exposed.

A brand new liquid cooled V-Twin 1125cc engine is responsible for the muscle behind the bike. The engine was produced in partnership with the Austrian-based BRP-Rotax engine manufacturer and will be the first liquid cooled engine to power a road-legal Buell bike.

“We designed the 1125R from the rider down,” said Erik Buell, chairman and chief technical officer at Buell Motorcycle Company. “The 1125R takes Buell to a new level of performance, while continuing to embrace the fundamental Buell principles of performance motorcycle design and offering a great sport motorcycle riding experience.”

The aggressive look of the bike is enhanced by an athletic riding position. Riders will benefit from Quiet Zone™ aerodynamics as air flows around the rider, allowing for unparalleled comfort and ultimately superior performance. Additionally, an interactive digital instrument panel will guarantee owners ease of use with everything at the touch of a button.  

The Buell 1125R joins the XB family as a distinct new Buell motorcycle platform.

Trilogy of Technology: The Gospel According to Erik
The three pillars of the Trilogy of Technology underpin every aspect of design at Buell Motorcycle Company: Mass Centralisation, Low Unsprung Weight, and Chassis Rigidity. The goal is always to create a motorcycle that handles intuitively, and predictably and accurately responds to input so that the bike behaves as an extension of the rider. Here are some examples of the Trilogy of Tech as applied to the new Buell® 1125R:

Mass Centralisation and achieving the optimal centre of gravity makes quick direction changes seem effortless.

  1. Compact 72 degree V-Twin engine places more engine mass along the centreline of the motorcycle than an across-the-frame engine, and allows the engine to be located further forward in the frame.
  2. Massive aluminium frame spars double as the fuel reservoir, to carry fuel lower on the chassis.
  3. Radiators are side-mounted in aerodynamic cowlings.This radiator location also allows the engine to be positioned further forward in the frame.
  4. The muffler is located below the engine, rather than high and behind the rider.

Chassis Rigidity allows the motorcycle to hold a precise line in spite of side-loads in corners.

  1. A new-generation Intuitive Response Chassis™ (IRC) is optimised for torsional stiffness.
  2. The engine is solid-mounted to the frame and acts as a structural member.
  3. The swingarm pivot point is located in the engine case structure, creating a more-rigid connection to the chassis.
  4. First OEM spec 47mm upside-down front forks are secured in rigid triple clamps.

Low Unsprung Weight enhances traction, manoeuverability and stability.

  1. New Buell ZTL2™ front brake system utilises a single disc and new 8 piston caliper assembly that is lighter than twin disc brakes.
  2. The New Buell ZTL2 front brake transmits forces from the rotor to the rim, so torsional load acting on the rest of the wheel is virtually eliminated. This permits the use of a very lightweight front wheel that also helps reduce steering inertia.
  3. The rear brake caliper is mounted directly to the swing arm.
  4. A Goodyear Hibrex® final drive belt with Flexten® Plus technology weighs just 480g, compared to drive chains that can typically weigh around 2Kg.

The Helicon Engine
The Buell 1125R Helicon™ powertrain is a high-performance, 72 degree liquid cooled V-Twin specified and designed in partnership with BRP-Rotax, one of the premier recreational engine manufacturers in the world. Buell provided a detailed specifications list to BRP-Rotax, outlining powertrain requirements to meet the

performance goals of the Buell 1125R. As well as providing the detailed design specification, the Buell engineering team also directly contributed technology and engineering in a number of key areas, including the compensating front sprocket, transmission layout, the shift mechanism, engine cases, pistons, intake, exhaust, and EFI system. All major components of the Helicon engine are unique to Buell and have been developed specifically for the new Buell® liquid cooled platform. A few components, such as the stator and various fasteners, are used in other BRP-Rotax products. The new engine will remain exclusive to Buell and will be assembled by BRP-Rotax in Austria. The Buell 1125R motorcycle will be assembled by Buell in East Troy, Wisconsin USA. Its V-Twin design perpetuates the look, sound and character that have always helped to define the Buell sport riding experience.

Rather than design the Helicon to fit a specific displacement category or racing classification, Buell and BRP-Rotax developed this powertrain to meet a customer experience specification, both in terms of its power output and delivery, and its contribution to the overall performance of the Buell 1125R. The engine’s generous 1125cc displacement allows it to make abundant peak power with a broad powerband free of dips and flat spots. The engine has been designed to make broad useable power that will enhance any riding experience.

Helicon features:

  1. 72-degree cylinder angle and a very compact crank case and cylinder head design allow the engine to be located far forward in the chassis, distributing 54 percent of the vehicle weight to the front tire.
  2. The 72-degree V-angle provides a straight path for the down-draft intake system.
  3. A cylinder angle of 72 degrees was chosen because it provides the right balance between compactness and reducing vibration. The engine is also fitted with three balance shafts: two balancers for canceling primary rotating imbalance and a third balancer for canceling the rocking couple.
  4. The displacement of 1125cc was chosen to create an optimal 103.0mm bore x 67.5mm stroke configuration – generous bore for more valve area and better breathing and short stroke for reduced friction, increased rpm range and instant throttle response.
  5. The engine has a low-inertia flywheel for a quick-revving performance and smooth shifting.
  6. The engine is a stressed member of the frame and contributes to overall chassis rigidity. The swingarm pivot is located in the engine cases.
  7. Each cylinder features twin overhead cams with a self-adjusting chain drive to the intake cam and gear drive from the intake to the exhaust cam. This design requires less space over the cylinder head than a two-sprocket design, allows the engine to be located further forward, and reduces engine weight.
  8. Valves are actuated with light weight finger followers and adjusted with shims, a design derived from Formula 1 engine technology.
  9. Finger follower valve actuation reduces friction, permits a quicker valve opening, and eliminates valve float. This design also allows a steep valve angle of 18 degrees which aids the downdraft fuel injection system. The design of the follower retention system makes shim replacement quick and easy, reducing maintenance costs. Valve covers are magnesium to reduce weight.
  10. Primary balancing with three internal shafts reduces chassis weight by minimising vibration isolation requirements.
  11. Dry sump oiling reduces internal windage losses. An integrated oil reservoir is located in the lower left side of the crankcase casting to lower the centre of gravity and help keep the engine compact.
  12. Buell® DDFI3 Electronic Fuel Injection is a closed-loop system for precise mixture control, resulting in smoother throttle operation and better fuel economy. Dual downdraft 61mm throttle bodies provide superior intake air flow.
  13. Ram-air system pressurises the air box for a peak performance gain of up to 5 percent. The air intake is located between the front fork legs and below the fairing. Air flow to this area and the size and shape of the intake were optimised using computational fluid dynamics (CFD) models. The 12-litre airbox is designed to accommodate a large air filter and to be easy to service.
  14. Twin side mounted free flowing radiators are mounted longitudinally within aerodynamic cowlings. The position of the radiator system lowers the centre of gravity and centralises mass, and allows the cowlings to direct free-flowing air to each radiator. The cowlings have an internal vane (splitter) to split airflow efficiently and were designed with computational fluid dynamics (CFD) models to optimise air flow at all speeds and to create a pressure differential around the radiator to pull air through the core. Hot air is also exhausted away from the rider for enhanced comfort.
  15. The exhaust system features a large-volume muffler mounted below the engine to optimise cg location and mass centralisation. The muffler is tuned to produce a linear horsepower and torque curve without the added cost, weight and complexity of an active exhaust system. A Helmholtz chamber within the muffler further reduces noise output. Twin brushed stainless exhaust outlets produce less exhaust noise than a single side mounted outlet.

Chassis and Suspension Features

  1. An all-new Buell IRC (Intuitive Response Chassis™) is made in the USA and is the stiffest chassis ever offered by Buell. Its rigidity is aided by the engine, which is a rigid stressed member of the chassis. The inner frame incorporates air-flow channels that create a low-pressure area behind the engine to draw hot air out of the rear of the motorcycle. Utilising patented Buell Fuel in the Frame technology, the aluminium frame spars double as the fuel reservoir.
  2. The stiffness of a new cast-aluminium swing arm has been highly-tuned for optimum performance in the 1125R. The pivot point of the cast-aluminium swing arm is located in the engine cases to create a more direct connection between the rear wheel, the frame, and the front wheel. By placing the swing arm pivot point forward in the engine cases, the anti-squat properties and suspension control of the 1125R were optimised. The rigid connection to the engine was used to optimise the stiffness of the swingarm in relation to the overall chassis.
  3. A fully-adjustable Showa® rear shock/spring unit features an external piggyback reservoir for good heat dissipation. To reduce weight, the shock is mounted directly between the frame and the swingarm without linkage, and its off-centre placement optimises airflow through the motorcycle.
  4. Fully-adjustable Showa 47mm upside-down front forks and new triple clamps stiffen the torsional response of the front end and improve steering response. A new fixed bushing slides against the hard-chrome surface of the fork tube, reducing friction. Titanium fork caps reduce weight. Compression adjustment can be made with a simple hex-key tool.
  5. Wheelbase is 1384mm. Rake is 21 degrees. Trail is 83.8mm.

Brake System Features

  1. New Buell ZTL2 ™ (Zero Torsional Load) front brake utilises an eight-piston caliper based on a design developed in-house for the Buell® XBRR production racing motorcycle. The eight-piston design offers a larger pad surface, optimises heat-dissipation capability and allows even pressure distribution over each of the four pads in the caliper.
  2. The caliper casting was optimised for clamping stiffness, yielding a more progressive and connected braking feel to the rider. A single 375mm stainless steel rotor is mounted directly to the wheel rim. This design produces outstanding stopping power and weighs less than a dual-disc system. And because braking forces are transmitted directly from the rotor to the rim, torsional load acting on the rest of the wheel is virtually eliminated. This permits the use of a very lightweight front wheel that also helps reduce steering inertia.


  1. The rear brake utilises a 240mm stainless steel rotor gripped by a two-piston caliper. The caliper is mounted directly to the inner surface of the swing arm, so it is hidden from view and also weighs 680g less than a typical rear-brake design.
  2. Front and rear brakes are fitted with braided steel brake lines for optimal feel and braking performance.
  3. The front brake hand control is adjustable for reach. Foot controls (brake and shifter) feature toe pegs that adjust to rider foot size.

Clutch and Transmission Features

  1. HVA™ (Hydraulic Vacuum Assist) Slipper-Action clutch features hydraulic actuation from the hand control with assistance from engine vacuum for lighter clutch effort. The vacuum assist also produces the same effect as a “slipper” clutch for more controlled engine braking during high-speed down shifts.
  2. A six-speed, close-ratio transmission is an oblique stacked configuration that is tilted to minimise overall powertrain length and allows the engine to be optimally placed within the chassis. Gear ratios were selected to allow the engine to remain within its optimal power band at typical operating speeds.
  3. A Goodyear Hibrex® final drive belt with Flexten® Plus technology weighs just 480g, compared to drive chains that typically weigh around 2Kg. The belt system is clean, quiet, light and extremely strong.


  1. Quiet Zone™ cockpit aerodynamics were developed using computational fluid dynamics (CFD) models and experience gained in development of the Buell XBRR production racing motorcycle. The shape of the fairing and windshield optimise air flow over and around the rider for reduced drag and enhanced rider comfort.
  2. Computational fluid dynamics (CFD) models were also used to design the efficient, aerodynamic shapes of the radiator cowlings, which direct radiator heat away from the rider.
  3. The fairing incorporates a six-bulb headlight system for brilliant road illumination at night. Two bulbs are illuminated in daylight running mode for enhanced visibility in traffic.
  4. LED turn signals are incorporated in the aerodynamic mirror housings where their placement and brilliance are more visible to other drivers.

Rider Interface

  1. The Buell® 1125R offers an athletic yet comfortable riding position with a repositioned foot peg location that provides 50 degree lean angle.
  2. Quiet Zone™ cockpit aerodynamics optimises air flow around the rider.
  3. Brake and clutch hand controls are adjustable for reach.
  4. Foot controls (brake and shifter) feature toe pegs that adjust to rider foot size.
  5. Switch gear is pre-wired for accessory heated hand grips.
  6. Instrument cluster features:
  • Large analog tachometer
  • Digital speedometer on an LED screen visible within a 50-degree angle of view
  • ODIS (Onboard Diagnostic Information System) displays service codes
  • Four-digit security code system immobilises the ignition
  • Lap timer and splits
  • Ambient air temperature
  • Coolant temperature
  • Two trip odometers
  • Instantaneous miles per gallon
  • Average miles per gallon
  • Low fuel indication with trip count

Buell 1125R Colours

Bodywork: Midnight Black
Wheels: Diamond Blue
Frame and Swingarm: Diamond Blue
Engine Trim: Fusion Bronze

* All specifications are US approved and are subject to change after European Homologation

Buell® 1125R Technical Specification:

All specifications are US approved and are subject to change after European

Type Liquid cooled, 72° V-Twin
Displacement 1125 cc
Bore and Stroke 103 mm x 67.5 mm
Compression ratio 12.3:1
Fuel system 61 mm down draft DDFI III fuel injection
Exhaust Tuned, tri-pass resonance chamber with integral
helmholtz tuning and mass centralised mounting
Intake Zero resistance air box
Power* 146 hp @ 9800rpm (EU Standard EC 95/1)
Torque* 82 ft. lb / 111 Nm @ 8000 rpm (EU Standard EC 95/1)
Lubrication Dry sump

Frame Aluminum frame, fuel in frame
Wheelbase 1384 mm
Rake 21°
Trail 83.8 mm
Front fork 47 mm Showa® inverted fork with adjustable compression
damping, rebound damping and spring preload
Rear shock Showa® coil over monoshock with adjustable compression
damping, rebound damping and spring preload
Suspension Travel
Front wheel 120 mm
Rear wheel 127 mm
Front brake ZTL2-type brake, 8-piston, fixed caliper, 375 mm single
sided, inside out, stainless steel, floating rotor
Rear brake 240 mm stainless steel, dual piston, direct mount caliper,
fixed rotor
Front wheel 6-spoke ZTL™ cast aluminium, 3.5 in x 17 in
Rear wheel 6-spoke ZTL™ cast aluminium, 5.5 in x 17 in
Front tyre Pirelli® Corsa III 120/70 ZR-17
Rear tyre Pirelli® Corsa III 180/55 ZR-17

Lean Angle
Soft Contact: Right 48°
Soft Contact: Left 48°
Hard Contact: Right 50°
Hard Contact: Left 50°
Fuel capacity 21.2 litres
Dry weight 170 kg
Seat height 775 mm
Overall length 1996 mm
Overall width 716 mm

Type Six speed straight cut gears
Ratio (1) 2.46, (2) 1.75, (3) 1.38, (4) 1.17, (5) 1.04 (6) 1.00
Primary drive Helical Gear, 0.544:1 ratio
Final drive Reinforced Goodyear® Hibrex® belt with Flexten® Plus
technology*, 2.593:1 ratio
Warranty 24 months (unlimited mileage)

*Hibrex and Flexten are registered trademarks of the Goodyear Tire & Rubber