Buell XB12S Lightning - something completely different
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Image Gallery ( 12 images )Now the XB12S motor arguably has its roots a half century in the prehistoric past given the rate of engine evolution going on around it. The Harley motor is not remotely near the forefront of engine design though it does a remarkably good job thanks to the addition of a range of innovative solutions and modern technology grafts which have taken well.
It looks and sounds like a two-wheeled, big bore hotrod motor and its specs share more in common with a fuel-injected V8 hotrod than they do with the overhead camshaft and sophisticated valve actuation of its much higher revving competitors.
The air-cooled, 45-degree pushrod twin is now fuel-injected but it snarls and spits just like the hot rods it emulates. That’s not to say there isn’t some very clever stuff happening. To keep the torque band fat, the new XB1200 engine is equipped with Buell InterActive Exhaust. An electronic actuator activates a butterfly valve housed in the muffler to adjust back-pressure by alternating between two gas flow paths. The engine ECM monitors engine speed and throttle position while activating the valve to optimise torque and horsepower for the riding condition. At wide-open throttle, for example, the valve is opened at low rpm to reduce back-pressure so the engine can gain rpm quickly. The valve closes in the mid-range to increase torque during acceleration, and then opens again at high rpm to deliver the most horsepower.
The Buell InterActive Exhaust has a rich, throaty exhaust note – open the throttle and the rumble of idle becomes a flat blat which takes on a rich tonal quality in the mid range. The motor is at its finest with an open throttle and between 3000 and 4000 rpm on the dial – it’s not your standard Harley drag-pipe music but it fits nicely with the feeling of the bike and with a 1200cc motor in the midst of its torque curve, the XB1200S simply beams you to a different speed.
That’s why the Buell is so rewarding. It can be ridden around town in a completely legal manner whilst having more fun than you can imagine – this is not possible on a 1000cc supersport. On the Buell, it’s just big grin territory.
If it were our choice, we’d get a set of cams to take 25% off the 100 horsepower top end, fattening up the low and mid-range torque curves in the bargain. And we’d fit heavier cranks so it is smoother at low speed, where it’s willingness to cough and spit necessitates one watchful hand over the clutch at all times. It’s current state-of-tune detracts from its low speed engine performance just a little too much.
Outside city limits, the XB12S is a happy participant, though it’s more a backroad motorcycle than a freeway machine. There’s no fairing and like all naked bikes, it gives you a full frontal to the elements. If your Buell is going to see a lot of country roads, and wind roar and buffeting aren’t your go, then choose the XB12S’ similar but faired variant, XB12R.
On a windy road the frame and suspension make light of every corner, setting you up for the surge of torque and glorious ripping exhaust as you slingshot from the exit of every turn. It’s fantastic fun in these environments, and more than makes up for the discomfort of riding it into the country on a freeway.
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