The Buell XB12 was the bigger-engined branch of Buell’s XB platform, made from 2003 until production stopped in October 2009. Its 1,203 cc V-twin used the same 88.9 mm bore as the XB9 but a much longer 96.8 mm stroke, trading revs for torque further down the range.
Buell XB12 at a glance
| Maker | Buell Motorcycle Company, United States |
|---|---|
| Production | 2003–October 2009 |
| Engine | 1,203 cc 45° V-twin of Harley-Davidson origin, air and oil cooled, 10:1 |
| Bore × stroke | 88.9 mm × 96.8 mm |
| Fuel system | electronic fuel injection, 49 mm throttle body |
| Gearbox | five-speed |
| Final drive | 14 mm toothed belt |
| Primary ratio | 1.50:1 (1.68:1 on the XB9) |
| Front brake | ZTL perimeter disc, 375 mm, six-piston caliper |
| Exhaust | 2-into-1 under the engine, with the Buell InterActive Exhaust valve |
| Front fork | inverted, 41 mm then 43 mm from 2005 |
Based on one source: there is no English article on the XB12, and this page is written from the Italian one.
History of the Buell XB12
The XB12 arrived in 2003 and lasted until October 2009. Its engine came from Harley-Davidson: a 45° air-and-oil-cooled V-twin of 1,203 cc with a 10:1 compression ratio, dry-sump lubrication, an under-engine 2-into-1 exhaust and two pushrod-operated valves per cylinder with hydraulic lifters and hydraulic clearance compensation. Compared with the Harley original and with the XB9, the bore stayed at 88.9 mm but the stroke grew from 79.4 to 96.8 mm, which gave more torque at lower engine speeds.
The rest of the package was tuned to match. The primary ratio was lowered from 1.68:1 to 1.50:1, the drive belt was made stronger and wider at 14 mm instead of 11 mm, and Gates belts gave way to longer-lived Goodyear items. A Buell InterActive Exhaust put a valve in the rear silencer, moved by a servo on the engine management according to engine speed and throttle position, to balance noise, torque and power; the header diameter also rose from 38.1 to 44.5 mm. At the front, a single 375 mm ZTL perimeter disc with a six-piston caliper is bolted directly to the rim.
The family expanded quickly. In 2004 came the Firebolt XB12R with a half fairing and the Lightning XB12S, a naked bike with a smaller screen. The XB12X Ulysses followed in 2005 with enduro-style handlebars, handguards, a grille over the headlight and knobbly tyres, and in the same year the inverted fork grew from 41 mm to 43 mm. For 2006 the swingarm was redesigned and made stiffer, and the XB12XT Ulysses appeared with side panniers and road tyres. In 2007 the airbox was optimised, the Dunlop D208 tyres were replaced by Pirelli Diablo, and in June the Lightning Scg arrived with a lower seat. The Ulysses versions received cooling, noise and reliability updates for 2009.
Design and features
- Long-stroke 1,203 cc twin: the same bore as the XB9 with a 96.8 mm stroke for stronger low-end torque.
- Buell InterActive Exhaust: a servo-controlled valve in the silencer balancing sound, torque and power.
- ZTL perimeter front brake: a single 375 mm rim-mounted disc with a six-piston caliper.
- One platform, many bikes: from the faired Firebolt to the enduro-styled Ulysses and the low-seat Scg.
Buell XB12 versions
- Firebolt XB12R (2004): the half-faired sport version.
- Lightning XB12S (2004): the naked bike with a small screen.
- Ulysses XB12X (2005): enduro-styled with tall bars, handguards and off-road tyres.
- Ulysses XB12XT (2006): touring version with side panniers and road tyres.
- Lightning Scg (June 2007): lowered seat and revised set-up.
The XB12 is the bigger brother of the XB9 and was eventually superseded by the water-cooled 1125R. More Buells are in the Buell collection.
Sources
- Buell XB12, Italian Wikipedia: engine, chassis, model history, variants
