Benda bends conventions with new design
By Ben Purvis
China's Benda - a brand that's rapidly spreading across Europe and entering the USA soon - is not one to follow trends. It sprung into international attention a few years ago with the launch of the mad-looking LFC700 - the first Chinese-made four-cylinder motorcycle and one that wears a wider rear tyre than any other production bike at a whopping 310 mm width - and followed that up with an array of cruisers including 250 cc and 500 cc V-twins and China's first V4 in the 500 cc Dark Flag model.
Now it's planning even more unconventional bikes, including a 250 cc roadster with a BMW-style boxer twin engine.
Design patents for the bike, codenamed BD250-3B, show that it uses a water-cooled boxer twin with cylinders prominently emerging from each side, paired to a tube-style chassis and upside-down forks hiding behind cowlings that give the look of a girder front end. Following the same thinking that's already employed on the LFC700, the headlight incorporates an air intake for the engine, feeding an airbox under the tank that's connected to the two cylinders via oversized pipes on each side.
Unusually, given that the engine's crankshaft runs longitudinally in the chassis, the bike uses a chain final drive rather than a shaft, indicating that the drive is turned 90-degrees inside the transmission.
There's also a mystery surrounding that transmission, as the front sprocket appears to be mounted unusually high, with what appears to be a secondary chain or belt connecting it, behind a cover, to a more conventionally-mounted output lower down on the left-hand side. Opposite the front sprocket, on the right-hand side of the bike, there's another cover with three fat pipes or cables attached underneath it.
It's possible that this cover hides a hybrid drive system, and those are the high-voltage cables leading to a three-phase electric motor, which could also explain why the sprocket sits so high: the conventional gearbox output would be connected, but a chain or belt, to the electric motor, which in turn drives the rear wheel.
That would allow the motor to drive the bike on its own, with the clutch disengaged and the engine turned off, or it could work alongside the conventional engine to give an extra performance boost. In either case, it could also operate as a generator to recharge the bike's drive battery, if it is indeed a hybrid.
In an unrelated development, Benda has filed patents for a new four-cylinder, across-the-frame engine attached to an unusual dual-clutch semi-automatic transmission. Unlike the DCT boxes used by Honda, which take their drive from one end of the engine's crankshaft and have two clutches mounted side-by-side, the Benda design takes drive from both ends of the crankshaft, with a clutch on each side of the transmission.
Essentially, it works like two, separate, four-speed transmissions to create an eight-speed dual-clutch semi-auto. That means the transmission on one side would deal with the odd-numbered gears - 1st, 3rd, 5th and 7th - while the other side is used for 2nd, 4th, 6th and 8th gears. At any one time, two gears would be engaged - 1st and 2nd, for example - and by disengaging one clutch and engaging the other (both would be computer-controlled), you achieve a seamless gear shift with no let-up in drive.
While Benda hasn't shown a bike using that transmission yet, the company has visited the semi-automatic market by launching the new Rock 707 cruiser, featuring a 692 cc V-twin paired to a transmission that's nearly identical to Honda's E-Clutch system, as offered on the CB650R and CBR650R.
Like the Honda design, it combines a conventional, manual foot-shifter with an automated clutch - nudging the shift pedal tells the computer, via a load sensor, whether you're shifting up or down, and the clutch and ride-by-wire throttle automatically coordinate their actions to give a smooth shift, blipping the revs on down-changes if required.
Also like the Honda E-Clutch design, Benda has retained a manual clutch lever as well, allowing the rider to override the automated clutch at any time, or to switch over to a fully-manual mode that makes it the same as any other bike to ride. However, the Benda system differs from the Honda version by using a hydraulic clutch instead of a cable-operated one.
Other notable features on the Rock 707 include air suspension at the back which automatically adjusts as you ride.
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