Husqvarna Nuda 900 and Nuda 900R get faux V-twin engines
By Mike Hanlon
September 6, 2011
We've already written quite a bit about the development of Husqvarna's new Nuda 900 and 900R and the promise of the Italian (formerly Swedish) brand under Teutonic (BMW) ownership to execute new thought, but we felt that the latest release of new info on the supermoto/naked-bike crossover to debut at Frankfurt warranted an update. We already knew the engine was derived from the BMW F 800 R motor with an increase in bore and stroke giving it 898cc, but what we didn't know previously is that the crankshaft has been altered from the F 800 R's 0-degree crank offset angle to 315-degrees, creating an engine with the feel and sound of a V-twin, but with the same excellent power delivery of the parallel-twin at small throttle openings, a characteristic not normally associated with v-twins. Details have also been released on the suspension and running gear packages of both models.
Husqvarna has added an extra 100cc to the liquid-cooled parallel twin BMW F 800 R motor by increasing the bore from 82mm to 84mm and increased the stroke from 75.6mm to 81mm. The compression ratio is now at a whopping 13.2:1, both inlet and exhaust vales have 1mm larger valves and almost everything else in the new motor is different to the original F 800 R thanks to the decision to run a 315-degree offset crankshaft. One of the reasons parallel twins fell from favor after their heyday in the fifties and sixties was their poor natural balance which caused harsh vibration. BMW's answer to this problem was to run a balance rod mechanism to cancel the engine's vibrations, so the Husqvarna's balance rod has also changed to account for the different harmonics caused by the eccentric crank throws.
This new configuration not only delivers a more aggressive v-twin racing feel and sound at maximum performance (just as Yamaha has done with its TRX850, TDM850/900 and 1200 Super Tenere engines), but Husqvarna claims it also vastly improves the power and torque characteristics of the engine which now boasts a maximum power of 105 bhp and torque of 100Nm. Despite all the increases in power and torque, the Nuda still delivers excellent fuel economy of 5 liters per 100 km, giving the Nuda approximately 260 kilometers between pit stops from its miniscule tank. For a back road bruiser, a range of 260 km will almost certainly compromise the best riding routes, but it's better than we expected and when you realize that the lump of metal that looks like a fuel tank is indeed a cowl, and the real fuel tank is under the seat, you forgive the designers for the small fuel capacity because they have gone to such extraordinary lengths to centralize mass near the center of gravity in order to provide a sweeter-handling machine.
The range-topping Nuda 900R wears suitably upmarket componentry with fully-adjustable 48mm Sachs forks and an Öhlins rear shock that offers compression and rebound damping adjustments plus ride height adjustment in addition to the normal spring preload adjustment. The Nuda 900R's sporting suspension gives it an 875mm seat height and a higher center of gravity as well as increased ground clearance and the ability to fine tune the ride on all levels.
The Nuda 900 comes gets lesser-spec 48mm Sachs forks (preload adjustable only) plus ditto on the rear Sachs mono-shock and a lower seat height of 860mm.
Husqvarna has given models radial brake calipers, though the 900R comes with higher-spec Brembo monobloc four-piston radial calipers racing brakes and 320mm discs up front. Both bikes use the same 240mm disc and twin piston caliper rear brake.
Beginning with the BMW F 800 R's trellis frame, length has been reduced by 50mm then the steering head was stiffened with 80mm tubing and the rake was tightened for more precise steering, enhancing the Nuda's suitability for urban environments. In many ways, Husqvarna's dirt bike design prowess will create a dirt bike for the road with sharp steering at low speeds and the accurate throttle response and grunt of a dirt bike for getting out of turns in confined spaces rapidly.
This could indeed yield a genuine urban weapon!