- 2 Cylinder, Supercharged, Liquid Cooled, DOHC, Counterbalanced, 60deg, V-twin
- 5 speed
- Horsepower @ RPM:
- 180hp @ 9100 RPM
- Torque @ RPM:
- 115 lb/ft torque @ 7600 RPM
- 1250 L
- Top Speed:
- 190 mph
Ever since Erik Buell started getting his hands dirty and borrowing Harley-Davidson engines to power his sports and later on superbike two-wheeled creations, we’ve been eagerly expecting the next big clue that there’s some competition around. The answer came with the 2010 Roehr 1250sc, an American-built superbike powered by a Harley-Davidson V-Rod engine and we really must say that the bike is no disappointment whatsoever. We support this affirmation with statements made by top motorcycle journalists writing for Motorcycle-USA and Motorcycle. These guys got the chance to ride the only prototype available and we tend to believe that what they’re saying about the bike is true.
Walter Roehrich is an innovative American engineer and the mastermind behind the 2010 Roehr 1125sc. His goal was to imagine, design and build an entirely American motorcycle and sell it to riders who prefer exclusivity and aren’t afraid to pay the price.
As mentioned above, the Roehr 1125sc is powered by a V-Rod engine and while that might not sound like a superbike revolution going on, the fact that the liquid-cooled, big-bore powerplant is being supercharged does ring a bell. This 100 percent American motorcycle benefits of an engine that was initially developed by Harley in collaboration with Porsche AG. This sounds worthy of a superbike, but wait to hear the rest: the 1,130cc liquid cooled, DOHC, eight-valve, 60-degree V-Twin engine that resulted was named the "Revolution" by H-D. The cylinder capacity of the V-Rod engine was later on increased to 1,250cc and the thing turned out being characterized by a 105mm x 72mm bore and stroke and 11.3:1 compression ratio once on the Roehr motorcycle. It was also coupled to a five-speed transmission, but it wasn’t enough, it was still naturally aspirated. This is how our innovative engineer ended up creating the RSS (Roehr Supercharger System).
The RSS was designed to develop maximum power when needed and for that purpose it has a special bypass valve which ensures that unneeded air is brought back into the compressor when the engine is idling, decelerating or is simply not highly demanded. Operating as a normally aspirated self, the engine disconnects and unloads the supercharger, thus reducing parasitic drag and increasing efficiency.
The only goal justifying this kind of effort is performance and having a 1,250cc liquid-cooled V-Twin, with a Rotrex C15-60 supercharger, producing 180 horsepower at 9,100rpm and 155Nm of torque at 7,600rpm is satisfaction guaranteed. The engine and five-speed transmission package is housed by a composite beam frame, which is made both of a mix of chrome-molybdenum steel and aluminum. Completing the high-spec chassis are the fully-adjustable Ohlins suspension, 17-inch Marchesini wheels and Brembo brakes. Overall, the bike weighs 432 lbs (196kg). If you believe that isn’t impressive, note that the engine only weighs 100 pounds.
Designing the Roehr 1125sc seems to have been a bit of a challenge because there really isn’t anything to call the “original superbike motorcycle look” around these parts of the worlds, so our friend Walter had to improvise, borrow and get his hands dirty...again.
“And while some of the components are sourced out, the design of the bodywork and its composite construction are done by Mr. Roehr himself.” - Motorcycle-USA.
“Roehrich spent many hours crafting the shape of the 1250sc, then used some off-the-shelf pieces to finish it off.” - Motorcycle
Riding the 2010 Roehr 1125sc wasn’t our pleasure, so we’ll simply give credit to the motorcycle writers that got the chance to swing a leg over the prototype. So, we’ve come to find that this motorcycle wasn’t built specifically for the track (although it will most likely never disappoint you) and it feels much better on the road.
“We were able to sample the machine both on the track briefly and more extensively on the roads. And first things first, this is a machine designed for the street…on the track, not everything is quite as glowing though.” – Motorcycle-USA.
Also, in order to keep the engine “in the zone” we hear that you’re better off changing 500 revs early that you’d normally do because this engine hits redline before 10,000rpm.
“The small V-Rod tachometer could be a bit more conspicuous, but shifting, say, 500 revs early hinders acceleration only as much as an extra carry-on bag does on a Boeing 737.” - Motorcycle
Most likely the Roehr’s biggest disadvantage is the $42,500 price tag, but if we take in consideration the fact that this is a bike addressed to riders who will rather stay exclusive than simply go ahead to buy a Gixxer and join the club, we’re suddenly starting to look with different eyes at that sum. You also get a custom-painted Arai helmet for the money.
Without the intention of comparing this engineer’s enormous effort and dedicated work with any of the Japanese or Italian factory motorcycles, we’ll just go ahead and say that this is yet another big step in putting America on the superbike motorcycle map. Congratulations!
Engine and Transmission
Engine Type: 2 Cylinder, Supercharged, Liquid Cooled, DOHC, Counterbalanced, 60deg, V-twin
Bore x Stoke: 105mm x 72mm
Compression ratio: 11.3 / 1
Power: 180hp @ 9100 RPM
Torque: 115 lb/ft torque @ 7600 RPM
Clutch: Wet, multi-plate, hydraulic actuation, slipper type
Transmission: 5 speed
Final drive: 520 O-ring chain
Chassis and Dimensions
Chassis Type: Steel/aluminum composite beam frame, 4130 steel/ 6061 aluminum
Front suspension: Ohlins 43mm fully adjustable upside-down fork with TiN
Rear suspension: Ohlins fully adjustable linkless monoshock
Front Brakes: 2 x 330mm semi-floating discs, radially mounted Brembo 4 piston calipers.
Rear brake: 245mm single disc, with 2 piston Brembo caliper
Front Wheel/tire: 3.5 x 17 forged aluminum 10 spoke Marchesini, 120/70 ZR17
Rear wheel/tire: 6.0 x 17 forged aluminum 10 spoke Marchesini, 190/55 ZR17
Wheelbase: 56 inches (1422mm)
Rake/trail: 23.5deg. / 89mm
Seat height: 31.5 inches
Dry weight: 432 lbs. (196kg)
Fuel tank capacity: 3.2 US gallons
Reserve fuel: .5 US gallons
Ergonomic design combined with traditional placement of the controls helps the rider become one with the machine.
The power to stop:
Superb braking is achieved from the two semi-floating discs and radially mounted Brembo 4-piston calipers.
BiMetal composite frame:
Computer aided design, engineered for maximum rigidity and light weight, providing ultimate control and stability.
Wheels and tires:
Forged aluminum wheels and Pirelli high performance tires provide low unsprung weight and the ultimate in street tire performance.
A symphany of tuned power:
The custom muffler and exhaust system is tuned to match the power of the supercharged engine.
The final drive:
Chain driven for strength and reliability with a race proven quick change rear sprocket carrier.