Honda's new VFR1200 uses concentric...
Honda's new VFR1200 uses concentric transmission shafts and two clutches (shown in red and blue) to expedite gear changes.
Honda has just released the 2010 VFR1200F, a motorcycle with a split personality. While the standard VFR has some interesting innovations, the automatic version breaks completely new ground. Both versions use Honda's Unicam cylinder-head design from the four-stroke dirtbikes. The heads are smaller and lighter than twin-cam designs. The V4 layout is unique in that the rear two cylinders are spaced closer together than the front two, making the engine narrower at the rear to help ergonomics and packaging. There's a new shaft-drive setup that uses a shaft located below the swingarm's axis, resulting in less torque reaction than a conventional shaft drive but perhaps more than BMW's Paralever or Kawasaki's and Moto Guzzi's similar setups. Throttle-by-wire, ABS and linked brakes add to an impressive résumé.
But the real technological fireworks come on the automatic version. Double-clutch manual-automatic gearboxes first appeared on automobiles to speed gear-change times. They basically allow the next gear to be engaged while the gearbox is still in the previous gear. How? On the VFR, there are two transmission mainshafts and two clutches. One shaft provides engine power to first, third and fifth gears. The second powers second, fourth and sixth. The two shafts are concentric, one more or less conventional-looking and the other larger in diameter and hollow, one fitting over the other. One clutch attaches to each shaft.
Harder to quantify are the benefits. An automobile's manual gearbox is a slow-shifting beast, and the dual-clutch box offers a big benefit in speed. Conventional motorcycle gearboxes are pretty quick already, and most can be upshifted without the clutch if you really want to shift fast, so a dual-clutch transmission offers a smaller improvement. Motorcycles don't need this change as much as cars did.
What I suspect this transmission will do best is offer a very "upscale" feel to the sport-touring rider. If it's done right, this transmission should make the Gentleman's Express even more gentlemanly and express-like. If the dual-clutch transmission is an answer to a question that few have asked, it's nonetheless a worthy technical exercise and one that once again highlights Honda's technological ambitions and abilities.
The VFR's clutches are hydraulically actuated, with fluid pressure rather than spring pressure providing engagement. Two hydraulic pumps, driven by electric motors, power the system. The clutches are similar but not identical, with the 1-3-5 clutch-also termed the "starting clutch"-significantly beefed-up.
Though the transmission is a single unit, it can best be visualized as two transmissions, each with its own clutch. With first gear and its associated clutch engaged, second gear can also be engaged, ready for the shift, with its clutch disengaged. When it's time to change gear, the shift is performed by the clutches. The first-gear clutch disengages and the second-gear clutch engages. It sounds complex, but it happens very quickly. Auto-motive versions shift in as little as 8 milliseconds, and the VFR's transmission should show similar speed.
The VFR rider can choose fully-automatic mode or manual-automatic, in which he shifts with buttons on the left handlebar, using the forefinger for upshifts and the thumb for downshifts. These buttons are analogous to the paddles on the steering wheels of some sports cars.
If the transmission, its clutches and hydraulic systems seem complex, the electronics and the logic controlling the hardware is certainly more so. The rider directs the action through the twistgrip. Electronics then determine the opening of the throttle butterflies and the engagement of the first-gear clutch. In fully-automatic mode, electronics will continue the shift sequence. In manual-automatic mode, the rider chooses shift points, but the electronics determine throttle position and clutch action during shifts. The coordination and timing of these events is further influenced by how hard the rider chooses to accelerate. There is literally no mechanical link to the engine/transmission in this bike. Every rider command is mediated by electronics.
This technology won't be without its downsides, however. We don't yet know the VFR's price, so the extra cost in dollars isn't known. The cost in weight is known, the automatic version said to weigh 623 pounds-32 more than the standard model, which equates to a substantial 5 percent increase on a bike that isn't light to begin with.