Honda’s E-Clutch Is a New Take on Automated Shifting

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Kevin Cameron has been writing about motorcycles for nearly 50 years, first for <em>Cycle magazine</em> and, since 1992, for <em>Cycle World</em>. (Robert Martin/)

In 1940 Oldsmobile introduced “the first fully automatic transmission to be mass-produced in the US” (page 129, Changing Gears by Philip G. Gott). Simplifying the operation of cars attracted many potential buyers who had found driving while synchronizing the operation of clutch, throttle, and gearshift lever dauntingly difficult.

Manual-shift gear transmissions used to be referred to as “standard” and automatics were dismissed as “slushboxes,” but today more than 98 percent of autos made in the US are equipped with automatic transmission.

There have been many attempts to accomplish a similar revolution on two wheels, but to date no comprehensive revolution has occurred. Despite that, new technical means of automating shifting continue to emerge.

Paralleling the automotive case, one motivation for offering automatics is that with the majority of auto drivers choosing automatic transmissions, there must be sales resistance to clutch-and-foot-shift bikes. If so, the right kind of automatic should attract new buyers. This was probably the driving force behind Honda’s 1973–88 “Hondamatic,” which combined a twist-and-go hydraulic torque converter with a two-speed foot shift.

There have been two streams of automatic drive development:

1. To automate in various degrees the normal clutch and multispeed gear transmission. An early attempt in this direction was Chevrolet’s “Vacuum Shift” of 1941–1948, in which a vacuum cylinder assisted the motions of the column-mounted shift lever, notionally making shifting a two-finger operation. Motorcycle manufacturers continue to offer drivelines of this basic type.
2. A completely different driveline, lacking clutch and shift lever. In this category are belt Continuously Variable Transmissions (such as <a href="https://www.cycleworld.com/2009/05/05/riding-impression-2008-aprilia-mana-850/">Aprilia’s Mana 850</a> with electronically controlled CVT), hydrostatic drives based on variable-stroke hydraulic pumps, and automotive-style automatics consisting of a ratio-changing hydraulic torque converter coupled to an automated epicyclic gear train providing two or more ratios to further broaden range. Examples of this are the Fuji “Superflow” scooter of the early 1960s and “Hondamatic.”

Opposing such experiments is a lingering tradition—a belief that motorcyclists regard mastery of clutch, throttle, and shifting as a “social gateway” through which beginners must pass in order to become “real motorcyclists.” The persistence of manual shifting in racing used to be cited as supporting this, but with such developments as “paddle shifting” in F1, this is outdated nonsense.

More recently, the rising popularity of electric bicycles and electric or automatic scooters has generated a population of riders who are two-wheel savvy but accustomed to twist-and-go operation. It’s reasonable to assume that a twist-and-go motorcycle could be an attractive next step for these riders.

Honda’s hydrostatic drive automatic DN-01, during its 2009–2010 importation to the US, was touted as an ideal beginner’s bike because its continuously variable hydrostatic drive provided three “human-friendly” modes of basic twist-and-go riding. The modes were Drive, Sport, and Manual. “Drive” provided basic automatic functionality, “Sport” could on demand hold engine rpm constant at peak power to maximize acceleration, and “Manual” restored foot-shifting through a computer-simulated six speeds, causing engine note to rise and fall in traditional fashion.

Honda’s DN-01 used a continuously variable hydrostatic drive. <i>Honda</i>

Unfortunately, the high $14,599 price, rising to $15,499 in its second year, strained beginner budgets—especially in the down economy of those years. If that wasn’t enough, DN-01 was, well, odd-looking.

More recent and more successful is the Dual-Clutch Transmission (originally invented for Citroen in 1939) adopted by Honda on some models—most notably optional on Gold Wing tourers, where it has been adopted by a majority of riders, as follows:

August 2020 release from Honda: “[…in the past 12 months] 57 percent of Gold Wings and 38 percent of Africa Twins sold in the US had DCT transmissions.”

DCT allows “seamless operation,” meaning that torque flow to the rear wheel is uninterrupted as its automated shifting and clutching take place. This has advantages in touring as control software removes the need for downshifting on hills or during passing or on-ramp acceleration. Off-road, it allows the rider to focus on riding while the transmission attends to itself. A DCT can operate either automatically or in a manual mode.

Honda’s latest effort in this direction is called “E-Clutch.” First of all, it is switchable: If the rider prefers to clutch and shift conventionally, E-Clutch can be switched off. But if E-Clutch is on, all the rider has to do is operate the shift lever and throttle, even when accelerating from rest or coming to a stop. This is accomplished by automating the operation of a conventional clutch. With the engine running, click the shift pedal into first. E-Clutch makes this possible by first disengaging the clutch, then engaging first gear. Turn the throttle and E-Clutch makes a smooth, no-stall engagement and away you go. Time for second gear? Click the lever to second and again, E-Clutch allows this by disengaging, shifting to second, and reengaging the clutch with all the skill of a seasoned rider. Same with downshifts.

Honda’s E-Clutch automates the operation of the clutch. The rider can change the function from automatic to manual with a press of a button. (Honda/)

This allows the rider to continue to control “the music”—the dynamic rise and fall in engine note as the rider shifts up and down through the gears, but without having to manage the clutch.

To quote from Honda’s European Media Newsroom, “The Honda E-Clutch manages clutch engagement and disengagement based on its reading of parameters including vehicle speed, throttle opening angle, engine rpm, pressure on the shift pedal, clutch motor reduction gear angle, engine countershaft speed, and gear position. The clutch is operated through an actuator unit with two motors situated inside the right-hand engine cover. As the clutch is engaged or disengaged, the engine’s ignition timing and fuel injection are also controlled, resulting in smooth, shock-free shifting in any situation.”

Using data from multiple parameters, Honda’s E-Clutch automatically manages the engagement and disengagement of a traditional wet, multiplate clutch. (Honda/)

Aside from its computer logic and control software, E-Clutch consists of two small electric motors driving a gear train that rotates a sector gear controlling clutch engagement. Total weight is cited as 4 pounds, 6 ounces.

As noted above, E-Clutch can be switched off, leaving driveline control entirely up to the rider, in a 100 percent traditional style.

As with the coming of fuel injection, electronic ignition, and electronic rider aids, some will object that such systems add complexity and cannot be owner-serviced in the field. Just remember that automotive automatics, each one containing as many as 800 unique parts, quickly became (and remain) solidly reliable.

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