Frustrated racer Erik Buell started designing street bikes in 1985 with the avowed intention of building America's first world-class sport bike. Considering that the best US-built motor he could get was from the outdated, overweight and inefficient 1203cc Harley-Davidson Sportster, what he has done with it is astonishing.
By thinking outside the box he has built a bike no bigger than a 250cc GP machine around Milwaukee's cruiser lump, a litre-class V-twin both lighter and shorter than the new Ducati 999 that has a number of features never before incorporated into a production street machine.
If, in the final analysis, it's let down by the limitations of the motor, it's still a superb effort, a magnificently rideable street bike with phenomenal handling and Buell's best build quality yet.
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Motor and transmission
The torque curve is almost flat and the Buell pulls strongly from 2000 to 6000rpm. Buell American Motorcycles is now a subsidiary of Harley-Davidson and the power for the Firebolt comes from a juiced-up Sportster engine. Buell started with 88.9mm Sportster 1200 pistons on a specially lightened short-stroke (79.8mm) crankshaft for a 984cc motor that revs safely to 7500rpm - about as far as you can push the XL motor - that was developed in the middle 1950s - without reliability problems.
The restrictive T-shaped Harley intake manifold is gone (that’s a prerequisite for getting any real muscle out of a Milwaukee lump) in favour of twin digital fuel injectors squirting into 45mm vertical throttle bodies. The result is 68kW at 7200rpm and a muscular 92Nm delivered at 5.5.
The revs rise and fall very quickly with less flywheel effect from the lightened crank and precise response from the fuel injection and the motor vibrates a lot less than previous efforts from Buell.
The torque curve is almost flat and the Buell pulls strongly from 2000 to 6000rpm; then, when European V-twins are just getting into their stride, the Firebolt signs off.
The Firebolt thunders up to 200km/h at which point the rev counter reads 6000.
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