Yamaha Electric Motocross Bike Patents

Admin · March 8

Although visually simple, Yamaha has filed patents that detail work it is doing on an electric motocross bike, which has some unique features. (Yamaha/)

Of all the use cases for electric motorcycles in competition, it’s motocross that arguably makes the most sense. Relatively short races mean you’re not hamstrung by huge batteries and the silence and lack of emissions open the door to bringing the sport to urban or indoor environments. Honda is already competing head-to-head with gas-powered MXers using its CR Electric Proto racer, with Trey Canard behind the bars. Now there’s a clue that Yamaha is heading in the same direction as it files patents for an electric motocross powertrain.

Yamaha is already forging ahead with electric competition bikes in the field of trials riding, using its TY-E 2.1 in competition against conventional rivals, and the company is now working on ways to translate the technology to motocross.

Yamaha’s TY-E electric trials motorcycle. (Yamaha/)

A new patent application from Yamaha specifically relates to a motocross bike and specifically explains how the transmission could be designed to improve traction and amplify torque to suit competition use. Yamaha faced a similar problem with the TY-E trials bike. While electric motors are renowned for their ability to provide maximum torque at zero revs, Yamaha found that a conventional direct drive between the motor and rear wheel wasn’t ideal for trials riding. It needed even more instant torque than the motor could provide and more control for the rider, so opted to add a flywheel and a conventional clutch. In trials riding, the design means riders can keep the motor and flywheel spinning with the clutch disengaged, improving low-speed balance and letting them unleash instant punches of performance by dropping the clutch and using the power stored in the flywheel.

For a motocross bike, that solution isn’t ideal—it adds size and weight to the powertrain—but Yamaha is looking for a solution to provide an extra thump of torque when needed. It’s also looking to improve the throttle feeling and has come up with a solution that incorporates a torsion damper into the transmission.

The electric MXer patents focus on its transmission that utilizes a clutch and flywheel to control power, unlike many EVs direct drive drivetrains. (Yamaha/)

The torsion damper is made up of two rotors mounted coaxially and connected to each other using springs. The input from the electric motor goes to the first rotor, the output to the transmission comes from the second rotor, so those springs provide an element of insulation between changes of speed of the motor and those at the transmission and rear wheel. They also work as energy stores—open the throttle rapidly, or close it and then quickly open it again, and the springs compress, storing energy, and then release it again to provide a brief punch of extra force at the rear wheel. It’s a system that’s lighter and more compact than the flywheel setup used on the TY-E while retaining some of the same benefits.

A closer look at some of the transmission pieces and the springs that help smooth delivery and store energy for quick bursts of acceleration. (Yamaha/)

What the patent shows is that as we move toward electric powertrains there will be a range of different solutions to adapt the technology to specific use cases. The clutch and flywheel energy store of the TY-E is tailor made for trials, the torsion damper suggested here has potential benefits in motocross.

While the illustrations in the patent are simplistic, they also give a hint as to the design Yamaha might be considering for its electric MXer. The TY-E already uses a carbon fiber monocoque chassis to house its battery, and it looks like the motocross bike might be following a similar route—there’s no conventional frame to be seen, just a boxlike battery case that makes up the main bulk of the bike and provides mounting points for the seat subframe and rear shock. Below it, the motor and transmission layout are like those of the TY-E, albeit without the flywheel and clutch. Although there’s no official announcement yet, and a patent is not conclusive proof that a project will reach production, don’t be surprised if Yamaha reveals an electric motocross prototype project in the coming months.

Trey Canard has been developing and racing Honda’s CR Electric Proto racer. (Honda/)