Powered by a supercharged
version of Harley-Davidson’s 1250cc, liquid-cooled, 8-valve, DOHC, 60-degree
v-twin, the Roehr 1250sc packs all of 180 horsepower, making it the fastest,
most powerful sportsbike built in America.
The bike is fitted with quality components like Öhlins suspension, 17-inch,
10-spoke Marchesini wheels, Brembo brakes, an Akropovic exhaust system and
120/70 (front) and 190/50 (rear) Pirelli tyres. The chassis is Roehr’s
chrome-molybdenum composite beam frame, which is said to be stiff and light,
and provides an excellent mix of quick steering and high-speed stability.
The bike weighs 192 kilos dry.
After apexing the final corner at
Blackhawk Farms Raceway and getting on the fat part of the rear tire, I dial up
the throttle of the Harley-sourced high-performance V-Twin to rocket me up the
front straight on this radical new American-made sportbike.
At this point you might assume I’m behind the bars of one of Erik Buell’s latest
sporting machines, but the fertile mind of Buell had nothing to do with the
innovative steed that is hurling me through the Wisconsin forest. And Buell
surely must be envious that the most powerful of his American bikes are down
almost 50 horsepower from the exclusive new Roehr 1250sc.
Roehr 1250sc: America’s newest sportbike.
Roehr (pronounced “roar”) Motorcycles is the brainchild of Walter Roehrich, an
Illinois-based engineer who has been designing and building his own sportbikes
for more than a decade. He began in the late-’90s with the Rv500, an
ultra-clever 500cc two-stroke V-Twin made by joining two Yamaha YZ250 cylinders
on a crankcase of his own design. Weighing just 315 pounds and producing 115
horsepower, it was a thrilling ride that ultimately was killed off due to
emissions hurdles for the two-smoker.
Roehrich next turned to producing a liter-sized four-stroke sportbike. The
Rv1000 was powered by a 120-hp 936cc V-Twin sourced from Sweden’s Highland. The
engine’s enduro roots made it super-light (under 100 lbs), contributing to the
bike’s feathery 335-lb claimed dry weight. But in an age of literbikes with
150-plus rear-wheel horsepower, Roehrich believed the Highland motor didn’t have
enough steam to be competitive. His next bike would have no such power concerns.
Enter the 1250sc, Roehrich’s latest creation that is scheduled to go into
production late this year. Like the aforementioned Erik Buell, Roehrich has
selected a powerplant from the Harley-Davidson catalog. But unlike any Buell,
the Roehr is powered by the Revolution V-Twin from Harley’s V-Rod lineup. Buell
himself apparently considered using the liquid-cooled 1130cc V-Twin but declined
because of the engine’s considerable weight of 197 lbs and its large size. Also,
its 110-rwhp wasn’t particularly stellar.
But Roehrich has found a smart and relatively simple solution to the
Revolution’s power deficit: supercharging. Rather than using a
positive-displacement supercharger, Roehrich has fitted a new centrifugal type
from Rotrex in Denmark. Mounted under the faux fuel tank and driven by a toothed
belt, the Rotrex unit weighs just 6.4 lbs. It basically operates like a
belt-driven turbocharger but pumps the intake system with pressurized air that
rises proportionally to engine speed. During idle, cruise and deceleration, a
bypass valve recirculates unneeded air into the compressor, reducing parasitic
drag and allowing the engine to function in its normally aspirated form.
It’s a brilliant system and operates as advertised. Power from a
positive-displacement blower comes on early and then tapers off, while a
turbocharger has a lag before coming on like gangbusters. In contrast, the
Rotrex supercharger supplies a very linear surge of power throughout its
powerband before running into a 9100-rpm rev limit. With a modest 8 lbs of max
boost, no intercooler is required.
As its name implies, the 1250sc is powered by the larger, 1250cc V-Rod engine
that debuted in 2008 with a slipper/gripper clutch system. Together with the
supercharger, it’s a monster. At just 4000 rpm, it’s already producing more than
70 ft-lbs of torque at the back wheel, rising in a gradual fashion to its burly
100 ft-lb peak around 8000 rpm. According to the Roehr-provided dyno chart,
horsepower builds in an uncannily linear trace that reaches to a 168-hp peak
shortly after 9000 revs.
Oddly for a bike with this much power, there are no steps in the powerband that
create the palpable surge of output like a normally aspirated engine. As such,
winding out the 1250sc through the gears at Blackhawk wasn’t as viscerally
exciting as expected. However, watching the V-Rod-sourced speedometer speedily
ratchet upward on Blackhawk’s two straightaways left little doubt about this
engine’s efficacy. Dual underseat Akrapovic mufflers (made for an R1) have
quieting inserts to keep the big Twin’s bellow relatively modest. The
supercharger whistles almost imperceptibly under a rider’s helmet.
When we arrived at Blackhawk, we were greeted by a tense but smiling Roehrich,
46, who was obviously nervous and relieved to come to this point of his project.
It was finally time to turn his baby loose on a quartet of motojournalists.
The 1250sc offers plenty to be proud of as it sits under cloudy skies while ace
lensman Tom Riles captures beauty shots. Its swoopy but clean bodywork reminds
of the lovely MV Agustas, as does the single-sided swingarm showing off a sweet
Marchesini forged aluminum wheel. Swanky Öhlins bits hold up both ends of the
bike, while Brembo supplies stopping power.
Roehrich spent many hours crafting the shape of the 1250sc, then used some
off-the-shelf pieces to finish it off. Those stacked headlamps came off a Buell
Firebolt, and the instrumentation is pure V-Rod. Stylish Barrac (not Obama)
mirrors offset the bike’s humble Ducati-sourced switchgear (which might be
replaced on production bikes).
The frame borrows ideas from Aprilia and Bimota in that a chromoly-steel main
frame is bolted and bonded to billet-aluminum sideplates. Thin-wall 4130 steel
is used for the perimeter-style frame spars and steering head section. The
swingarm is constructed from laser-cut chromoly sheet steel with inner
reinforcing ribs and pivots inside the machined billet-aluminum frame pieces
above the footpegs. Side-mount radiators from a Honda RC51 keep the wheelbase
acceptably tidy at 56.0 inches.
Using the large 60-degreee Revolution motor proved to be less challenging than
Roehrich expected. He says his engine is actually a bit shorter than a Ducati
90-degree V-Twin. However, the Harley motor’s cylinders are quite tall, forcing
Roehrich to cram in the supercharger and its oil tank and the battery in the
space normally reserved for a fuel tank. This forced a modestly sized 3.2-gallon
fuel tank to be squeezed in under the seat; it’s filled by an inlet placed into
the top of the tailsection.
Throwing a leg over the Roehr 1250sc is a bit daunting. Not only does it have
168 wheel ponies, it’s a priceless one-off prototype that, if crashed, would
probably cause its father to kneel down and cry. My first lap was purely
exploratory. Handlebars are placed similarly to a contemporary sportbike, but
there is a long gap from the rear of the dummy fuel tank to reach them. A wide
seat gives legs a stretch to reach the ground.
The Roehr steers into corners with a firm shove on the bars, not quite living up
to the sporty 23.5-degree rake and 97mm of trail listed in the spec chart.
Motorcyclist‘s Aaron Frank was the first rider out on the bike, and he noticed a
very soft rear suspension. Roehrich gave the handy hydraulic preload adjuster
several spins before sending me on my way. The back half now worked fine for me,
but the front end felt indefinite and the turn-in response was uneven.
The 43mm Öhlins fork fitted to the Roehr was originally intended for a Ducati
998, and its springs were having trouble coping with the added chassis pitching
caused by the tall engine and the bike’s 55% front weight distribution. A
quarter-turn extra preload was all that was left of the range, so we bumped up
the front compression damping in an attempt to compensate. The bike worked
better but still turned in imprecisely.
When we decided to break for lunch, Cycle World’s Don Canet came up with a
theory of what might be causing the Roehr’s odd steering response. His decades
of riding and testing bikes pointed us toward the steering-head bearings where
we found they were over-tightened.
I knew from the first corner I owed Canet a debt of gratitude, as the 1250sc now
steered with far greater precision. This, plus a track now heated by sunshine,
enabled the knee-dragging antics we all were hoping for. Now freed to
concentrate on other aspects of the bike’s performance, we were mostly pleased
by what Roehrich had wrought.
Response from the stock V-Rod fuel injectors was glitch-free everywhere except
for a slight kink when dialing on throttle from a closed position. A stiffly
sprung throttle is mostly to blame, but the linkage itself seemed to provide
excessive drag. Once the right grip is twisted open, you’d best be prepared for
a never-ending blast of grunt that sweeps through its five-speed gearbox like
nothing else on wheels. 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.
Getting the Roehr stopped in time for Turn 1 was accomplished with good feel
from the two-piece, four-pad front Brembos, looking similar to a Ducati 848’s
setup. Their bite is powerful yet not overly aggressive. Although the V-Rod’s
clutch has a slipper aspect to its design, it wasn’t slippy enough to prevent
the rear tire from locking during high-rpm downshifts. The 1250sc, at 432 lbs
free of all fluids, is nearly 200 lbs lighter and with a more forward weight
bias than the V-Rod.
The Roehr proved to be a bit more cumbersome than a Duc 1098 around Blackhawk’s
1.95-mile circuit and its many corners, but it could still be hustled around
quite smartly. A larger track might’ve allowed the Roehr to stretch its legs and
impress us greater. There wasn’t much use for the V-Rod tranny’s
cruiser-appropriate short low gear around Blackhawk, and a considerable gap in
ratios to second gear was a bit awkWard at the track. But the 1250sc, more than
any other bike I’ve ridden around a track, could easily carry a gear higher than
what would seem optimum.
Once the Roehr had its settings optimized, we were pleased with its overall
performance, and especially with its mountainous reserves of power. Yet there
were a few wrinkles yet to be ironed out. A rudimentary shift linkage had some
slop in it which may have contributed to a missed upshift, but Roehrich is
already working on a fix. Same for the fork springs, which are being replaced
with stiffer ones.
In the not-soon-to-be-addressed category is the small fuel tank that will limit
street sorties to under 100 miles before refueling. And, for my vertically
challenged body, the long faux fuel tank made it difficult to comfortably reach
the outside handlebar when hanging off and leaned over.
But otherwise, there is plenty to like here. First off, it’s simply gorgeous,
and I think it should assume the title of most dazzling American motorcycle ever
to wear a fairing. Second, it’s exotic in a way few others are – there are 50
units planned for production, making a Desmosedici seem like a CBR. Third, it is
built from top-shelf components that inspire pride.
It’s all enough to almost make you forget it costs $49,999. While that’s a big
stack of Benjamins, I’ve seen plenty worse ways to spend that amount on a
motorcycle. And most of them don’t come with a custom-painted Arai helmet like
The 1250sc certainly lives up to its billing as the fastest and most powerful
American production sportbike. How much is that worth to you?
Source Motorcycle.com 2008
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