The Buell 1,125R has a new heart

The latest offering from Harley's sports-bike division is a step in the right direction, says Kevin Ash

Less than two months ago, Erik Buell told the Telegraph that Buell, Harley-Davidson's sports-bike division, needed to understand sports-bike riders as well as Harley knows the cruiser market. He'd been on a mission to persuade them that they didn't need lots of horsepower while Buell's low-revving, tuned Harley engines offered riding satisfaction with only 100bhp.

Erik was holding something back: just two weeks later his company announced the 1,125R, powered by the Wisconsin factory's first liquid-cooled engine, indeed its first ever bespoke motor, designed and built to Buell's spec by Rotax of Austria, which also makes the Aprilia RSV's V-twin. At 146bhp, power is up almost 50 per cent on the air-cooled Firebolt, Buell's current sports machine, and compares with twin-cylinder superbikes from Ducati and Aprilia. That's what sports-bike riders really want.

If this is new ground for the Americans, the chassis at least is unmistakably Buell, with an obsessive concentration of the major masses around the centre of the bike to minimise the inertial moment and quicken steering response. Fuel is stored within the frame's main spars, the silencer hangs beneath the motor and most of the heaviest components are huddled together in the middle.

The distinctive rim-mounted front brake remains unique to Buell. This shortens the braking forces' load path and bypasses the wheel spokes, which as a consequence need to be less robust, reducing unsprung weight and enhancing suspension performance.

To improve stability at higher speeds, the wheelbase is 2.36in longer than a Firebolt's but, crucially, the engine is also more compact, so the swingarm is 3.34in longer. It sounds esoteric, but it matters: sports-bike designers strive to achieve the longest possible swingarm to maximise stability out of corners. They also aim for sharp steering geometry and light weight. The 1,125R has a very steep steering angle of 21 degrees, just 3.3in of trail and a dry weight of 375lb.

The engine's torque graph is so flat, the word "curve" is inappropriate. It's very forgiving of being in the wrong gear, driving you out of turns or trouble with willingness and speed. Get the light and dependable gearchange right and the bike charges out of turns, revving past its 10,000rpm power peak with a genuine twin-cylinder sports-bike bellow. It's deceptively quick, and would put up a convincing fight against the Italian opposition on the track if it had firmer suspension. On the launch, every journalist wanted to ride the bikes set up for the heaviest riders, as otherwise the forks were too soft. Hard braking resulted in a lot of dive, too, so it's worrying that Buell is planning to fit softer fork springs. Even on the road the suspension could do with more resistance, as the weight transfer when slowing hard upsets the chassis. The bike is agile and that long swingarm keeps it stable, but it does turn in slightly in lower-speed corners when more neutrality would be preferable.

The suspension is not helped by heat from the engine; this is directed away from the rider through the centre of the bike but then passes over the rear damper, which shows signs of fade at medium speeds in hot weather. Short riders still suffer as their legs rest against the metal frame rather than the plastic dummy fuel tank. Heat affects the braking, too; on the track several bikes suffered warped front discs and on the road my bike developed a harsh vibration. The rim mounting partially shields the disc from the airflow, which could be significant.

Over longer distances, engine vibration becomes a nuisance, numbing fingers at motorway speeds. Otherwise, comfort is good, with a more upright riding position than typical sports bikes, wide-set bars and a smooth airflow from the fairing. The seat is high for shorter riders, however.

More work is needed on the fuelling, as there's some roughness between 3,000 and 4,000rpm, but I've ridden worse and the bike isn't out until November so there's time to address it. The 4.7-gallon tank and reasonable fuel consumption (45mpg at slowish road speeds, according to the onboard computer, which irritatingly needs to be reset each time you turn on the ignition) are impressive. A breath of fresh air is Buell's attention to "damageability"; care has been taken to minimise the expense of dropping a bike, with plastic panels taking the brunt rather than frame or exhaust.

Looks matter to sports-bike riders but the 1,125R appears awkward; the fairing is too high and far forward and the other lines are confused. It's only available in black, but needs colour to add visual interest.

Several bikes at the launch were stopped by faults, including teeth shearing off a drive belt and electrical problems. These were pre-production machines, but previous showroom Buells have hardly impressed in this respect. The company understands better what sports-bike riders want, but some issues remain in delivering it.

It's not clear where the 1,125R fits in: it's not a full-on sports machine like a Ducati 1,098 or Aprilia RSV, or a streetfighter in the Aprilia Tuono/Ducati Monster mould, but something in between. Even so, the 1,125R is closer to the mainstream than the Firebolt and should win over more riders. But best allow Buell a year to hone it first.