Yamaha Patents Faux Clutch for Electric MXer

[Hugh Janus]

Yamaha is working on a faux simulated clutch to give riders of its upcoming electric MXer additional control. (Yamaha/)

We’ve already seen several patents relating to Yamaha’s development of an electric motocross bike, but the latest addition to the growing dossier of evidence around the machine is an intriguing one, revealing plans for an additional bar-mounted lever that replicates the effect of a clutch control.

We’ve already seen patents that Yamaha is working on an electric motocross bike to go head-to-head with Honda. (Yamaha/)

Yamaha is already very clearly aware that electric bikes, particularly in competition, can benefit from a clutch. The company’s TY-E electric trials bike has a flywheel and a mechanical clutch between the motor and the output side of its single-speed transmission. It lets riders spin the motor and flywheel without driving the wheel, giving a stabilizing gyroscopic effect, and to use the flywheel as a temporary energy store so raising the rpm and then dropping the clutch gives a momentary hit of power and torque that’s greater than the electric motor alone would allow.

However, an early patent for the company’s electric motocross bike showed that the mechanical clutch and flywheel are eliminated in pursuit of a more compact, lighter overall package, replacing them with a torsion damper between the motor and transmission. This uses two coaxial discs connected by springs that can also act as a temporary energy store—opening the throttle slightly while holding the bike on the brakes compresses the springs, and on releasing the brakes they’ll release that energy to get extra punch off the line.

Here you can see the location of the “clutch lever,” labeled 22. (Yamaha/)

The latest patent adds a faux-clutch lever to the mix, providing additional manual control over the bike’s power delivery and the regenerative braking level to mimic the feeling and effect of a real clutch without really disconnecting the motor from the transmission. We’ve seen a spate of similar ideas already this year, with Zero filing patent applications for its own simulated clutch control for electric bikes, and Kymco applying for patents on a system that includes not only a simulated clutch but also a simulated multi-speed gearbox. While the simple twist-and-go controls of electric bikes are appealing at the commuter end of the market, there’s clearly another stratum of riders who want more involvement and control.

In competition, where the Yamaha electric motocross bike is expected to go up against both electric rivals and combustion engine machines, that level of control is even more important, so adding the finesse that a clutch offers makes a lot of sense. The company’s patent application specifically focuses on how the “clutch” lever (the document calls it a “second operating member,” with the “first operating member” being the throttle) will be mounted and operated. Although it’s on the left bar, as you’d expect, it’s not the main lever on that side. Yamaha wants to eliminate foot controls from the bike altogether, so the larger lever on the left bar is for the rear brake. The faux clutch is controlled by a smaller lever above that one, to be operated by the rider’s forefinger alone. It sits where early four-stroke decompression levers used to reside.

The larger lever is for the rear brake and replaces a traditional foot lever, while the faux clutch’s lever sits right above it. (Yamaha/)

As well as the lever’s effect on the motor’s power and regenerative braking force—equivalent to engine-braking on an internal combustion engine (ICE) bike—the patent explains the feel of the control, showing how it will have dead zones at either end of its travel and progressive load that increases the further you pull it and then backs off as the lever is completely pulled in. That’s the same load pattern that you get from a normal clutch lever, making it feel familiar to riders used to conventional ICE bikes.

Although Yamaha’s patent initially applies to the electric motocross machine it’s developing, the idea is clearly one that could very easily make the leap to future battery-powered streetbikes as companies wrestle with the problem of building EVs that can appeal to riders who enjoy the level of mechanical engagement they get from combustion engine motorcycles.

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[Sir Fallsalot]

I've always said electric dirt bikes should have a clutch to help with control and i also thought Honda's DCT should have a clutch lever to disengage the Engine from the drive in emergency and to help with U turns fucking scary doing a U turn off camber on a DCT bike