Motorcycle specifications LeonhardtGunbus 410 2009 Sublime monster

a strong displacement is always attractive. Its depth, its strength, its sensations... Sometimes, it goes very far. On rare occasions, too far. But this is beyond. How to illustrate the immoderation of this machine? Figures? Yes, but it needs a more striking image. Something as enormous as its V-twin engine. Leonhardt has found the perfect way to illustrate its excess. A shot of the Gunbus 410 alongside a Harley Fat Boy. The Milwaukee custom is already a beautiful baby, long and heavy, but next to the Gunbus, it looks half the size!

voila , it's done, and we start to wonder and hallucinate about such a machine. In fact, Leonhardt describes it as "the biggest production motorcycle in the world" - a modesty that's not entirely exaggerated.

the Gunbus is huge. Almost 3.50 m long, 1 m longer than a Goldwing. Standing next to it, you could almost rest your chin on the tank. The tires are instantly reminiscent of monster-trucks: 38 inches at the front and 42 at the rear. The gumshoe that collects the power is 380 wide. Even the weight is off the scale. Its 650 kilos augur a machine capable of crushing anything in front of it.

but how do you fit a powertrain worthy of its size? A big 2-liter S&S or a V8 mill? Leonhardt preferred an uncommon, yet spectacular solution. First, he took a star-shaped aircraft engine (apparently a Wright R-1820 9-cylinder), cut it up and salvaged enough to make a V-twin. And then it hits. Its total cubic capacity of 6728 cm3 is mind-boggling. To put it on a scale, imagine fitting a can of Coke into the cylinder of a Suzuki SV 650; in each combustion chamber of the Gunbus, that's two magnums of champagne. With a bore of 156 mm and a stroke of 176 mm, the pistons pack a punch.

with 350 horsepower on tap, it's got a lot going for it - even if output is rather mediocre compared to a modern, technical motorcycle engine. Torque sets the record straight. Over 72 mkg of torque, it'll take two double-axle caravans off your hands. But what's even better is the availability of this torque: at just 1,900 rpm. Or perhaps it's the palpitations and noise of this engine... With moving parts like these, the block must give off big vibrations akin to a buffalo's heartbeat on cocaine.

p erhapsthe craziest thing about this machine is the seat. The seat is only 800 mm off the ground, the standard height for a roadster. So you can sit on it, and ride it. All you have to do is grab the huge handlebars connected to a parallelogram fork. But once you've settled in, you're not sure you'll feel very reassured... at the controls of a machine the weight of a cow, powered by the might of a Porsche.
The left foot must be terrified. Just a few centimetres away, a double drive chain connects the engine to the 3-speed gearbox. Fortunately, an openwork housing protects it. A reverse gear has been installed, indispensable for maneuvering such a massive machine.

although the Gunbus is equipped with huge calipers and 310 mm tracks, we can't help thinking that braking will be systematically agonizing. Yet who'd be tempted to go fast with such a monster? Or to test the limits of the chassis. The frame is homemade. A tubular structure in 25CrMo4 steel, designed in-house and featuring a simple, classic layout: an upper central beam connected to a double steel cradle.

the Gunbus 410 is not destined to be a museum piece or an exercise in dementia. It is produced in small series, just a few units a year. Hence the obvious care taken in its production. What does the number 410 stand for? No, its cubic capacity in American units: 410 cubic inches. For the record, a Triumph Rocket III is 140 ci...