Issue 131 : October - November 2003
The ACE
Take a Breva
Roland Brown
Bristol Show
Gremlins
Buell's on Test
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The ACE
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Buell's on test
Some racetrack turns are faster and some go on for even longer than the Carousel curve at the Road America circuit in Wisconsin. But I've never been cranked over so far, so fast, for so long as I was through the Carousel, where Buell's new Firebolt XB12R was held at 100mph and a dizzy angle for what seemed like an age. The Carousel would be fun on most bikes and it was a brilliant laugh on the XB12R. The smooth tarmac seemed to unwind up ahead at amazing speed, as I looked as far as possible round the seemingly never-ending curve, let the bike drift out towards the centre of the track, then gently pulled it back towards the brightly painted inside kerb that suddenly came into view. The original Firebolt XB9R would have been just as quick as the new model though most of the Carousel, because it has a near-identical chassis. But when I hit the apex and wound the throttle open to send the XB12R towards the following chicane, its new 1203cc aircooled engine hurled the bike forward with a strong, smooth surge of big-bore V-twin torque that the smaller-engined model could not have matched. It's logical that Buell, in expanding its range roughly a year after the launch of the new-generation Firebolt and Lightning models, should concentrate on the engines. Both of the American marque's XB9 models received rave reviews for their raw, aggressive styling plus their shared and innovative chassis, which featured a big twin-spar aluminium beam frame holding the fuel, and a swing-arm, also in aluminium, that doubled as the oil tank. Although most people who rode those XB9s had fun on the straights as well as in the turns, the engine's performance did not match that of the chassis. Despite the Buell development team's ability to extract an improbable amount of power from an aircooled, pushrod-operated V-twin based on Harley's ancient Sportster lump, the 984cc unit not only produced less peak power than many 600cc fours, but also lacked the low-rev punch you might expect from a big V-twin. The Yanks traditionally have an answer to problems like that: more cubes. Hence the arrival of the Firebolt XB12R and Lightning XB12S. The new bikes are visually and technically similar to their smaller engined siblings, but share a freshly developed aircooled motor whose extra 17mm of stroke increases capacity to 1203cc. Bore size is unchanged, so the cylinder dimension goes from an oversquare 88.9 x 79.8mm to a relatively long-stroke 88.9 x 96.82mm. Other mods include redesigned conrods and lighter valves with slimmer stems. The fuel-injection system gets wider throttle bodies (49mm from 45mm), and the exhaust header pipes have larger diameter for extra flow. The silencer remains in its traditional Buell position below the engine, and gains a so-called InterActive Exhaust valve, which uses an electronically controlled butterfly valve to adjust back-pressure by alternating between two gas flow paths. Similar in its effect to the familiar Yamaha EXUP and others, the Buell valve opens at low revs when the throttle is open, reducing back-pressure and allowing rapid rev gain. The valve closes through the midrange to increase torque, then opens again at high revs, boosting power. The result is a peak output of 100bhp at 6600rpm, compared to the XB9's 84.2bhp at 7200rpm; and a max torque figure of 109.7N.m at 6000rpm, an increase of more than 25 per cent. Other changes include a stiffer clutch spring and thicker final drive belt, to cope with the extra output. Elsewhere both XB12 models are unchanged from their smaller-engined siblings, apart from a new finish: red or black single-colour paintwork for each model, black-finished aluminium frames and swing-arms, and 17-inch wheels in a striking translucent amber. Because fuel lives in the frame, as before, the area below the dummy fuel tank can be used for the necessary power-boosting big airbox, rather than having that stuck out on the right as with earlier Buells.  The aggressive and eye-catching styling of both models is retained, along with the super-steep 21-degree angle of the upside-down forks, and the enormous 375mm-diameter single perimeter front brake disc with its six-piston caliper. That brake design allows a very light front wheel assembly (over 2kg lighter than a typical twin-disc set-up) and contributes to the Firebolt's dry weight figure of 179kg, very light for a big-bore twin. This and the ultra-short 1320mm wheelbase helped make the Firebolt nicely manoeuvrable at Road America. Although some bends of the picturesque circuit were streaked with hideous looking black overbanding reminiscent of a local council Friday afternoon road repair, this turned out to be less slippery than I'd feared, at least in the dry. We were using only half of the long circuit but there was still plenty to learn, and it was a credit to the Buell that it immediately seemed so light and responsive that I felt at home right away. Buell's short and rigid chassis really does make this one of the best-handling large capacity machines around, with a degree of flickability that allows quick and effortless direction changes, plus a stability that means you can throw the bike around with real confidence. Combine that with Dunlop D207 tyres that are not the world's stickiest, but have a very progressive feel when they start to slide (better than having more but less predictable grip), and the result was a very confidence inspiring bike. Never mind the chassis, though, because it's the new engine that differentiates this bike from the original Firebolt - and very welcome that difference was, too. Winding back the throttle out of every bend, normally with about 5000rpm on the redesigned tacho, resulted in a distinctly stronger kick than before, as the larger motor's extra grunt came flooding in. This would be a big asset on the road, and made the bike not only faster but also very easy to ride on the track. The only place where the XB12R struggled slightly was in the last turn, which had been added to cut the long main circuit into two. This blind right-hander was too fast for first gear but left the Buell pulling less urgently than normal from very low revs in second, losing time in the process. Everywhere else, the big V-twin grunted the bike forward with impressive strength and smoothness thanks to Buell's unique Uniplanar system, which partially rubber-mounts the engine while allowing it to contribute to chassis rigidity. Some riders complained about a stiff feel to the five-speed gearbox, which I found fine with the exception of one bike, whose lever was set too low. The reversed lever pivots in the opposite direction to the rider's foot, so precise adjustment is vital. Buell has lengthened the lever's toe shaft on all XB models, after complaints last year, but it obviously ain't perfect yet. At least the engine's flexibility and fact that there are only five ratios means you don't need to change gear as often as on most bikes. It's just as well the new motor has lots of midrange, because top-end power is a different story. With a redline at 7000rpm this Firebolt is even less rev-happy than the smaller model (whose limit is 500rpm higher), and its peak output of 100bhp is mediocre even by middleweight standards. That Road America chicane is followed by a straight and then a left kink, which is apparently truly scary on a fast bike. On the Firebolt, the kink was flat-out and barely noticeable, as the bike rumbled up to barely more than an indicated 130mph, with perhaps 10mph to come. At least it might give your driving licence more chance of survival. The Buell didn't lose any time under braking, where its big single disc shed speed very fast, and required less lever pressure than I recall the XB9R's apparently identical stopper needing on its launch last year. My only braking-related complaint came towards the end of several track sessions, when the bike lost power momentarily while accelerating out of a turn. Seems that fuel surge under hard racetrack braking can sometimes starve the pump, which is located low inside the frame. Erik Buell hadn't come across the problem before but thought it would be easy to cure. I've few doubts that this will be done, too, because one thing that the small Buell firm has shown in recent years is an ability to move fast to improve their bikes where necessary. That shows in small details, such as the Firebolt's wider and more useful mirrors, and the lower pillion footrests. And it should also be reflected in increased reliability of parts including the drive belt which, as well as being wider and stronger, has a longer, 25,000-mile service life. Warranty on the whole bike has been increased to two years, an encouraging and much needed sign. Most rival sports bikes would outrun even this more powerful Buell in a straight line, but it is a significantly quicker, more satisfying machine than the first Firebolt. And both the new Firebolt and Lightning are reasonably well priced at £7645 on the road, £650 more than the two XB9 models, which now cost £6995. Presumably one day Buell will use a more modern, liquid-cooled V-twin. But when you ride the bigger-engined Firebolt, it's easy to see why Erik Buell defends the simplicity and character of the aircooled V-twin.
The bigger engine's extra grunt was less obvious in the lower ratios, but on the twisty kart-track the big motor's crisp throttle response and ultra-torquey feel were very welcome. And when the time came for cutting fast laps, the minimal amount of gear-changing required, due to the engine's broad spread of power, was as big an asset as the high-barred Lightning's short, light and ultra-flickable chassis. (The XB12S also proved amazingly well suited to Buell's speciality, Battletrax: a fiendish timed contest, held on an almost exclusively first-gear circuit mapped out with cones in a large car-park.) Inevitably the Lightning's extra low-rev response made this bike even more temptingly wheelie-happy than the original XB9S, itself a true hooligan bike. And while the lack of competitive top-end horsepower might sometimes be annoying on the sporty Firebolt, the Lightning's upright and windblown riding position meant it felt quite fast enough on the long and open Road America track, as it headed towards an indicated 130mph maximum speed. Sharing the Firebolt's classy chassis meant that the Lightning also went round the circuit's faster turns very well, with no wobbles despite its poor aerodynamics and racy geometry. Low-rev grunt is such a vital asset for a naked bike that for most riders this XB12S would be a better bet than the smaller-engined XB9S, even though the £650 price difference would buy a decent lid and a set of leathers. No doubt about it, the Buell Lightning just got a whole lot better. Roland Brown  |
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Top gun road tester and MAG member Roland Brown cracks the throttles on a brace of Buells and finds they produce a smile...
Lightning XB12S