Return of the Hondamatic? Patent reveals clutchless CB1100

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Back in 1976 Honda made a bold move to make motorcycling easier and more accessible with the introduction of the CB750A Hondamatic: a twist-and-go version of its range-topping superbike of the era.

Now a patent application shows that the CB750’s direct descendent is the guinea pig for a new approach to the same idea. Hondamatic intended to mix the ease of use of a scooter with the performance of a sportsbike by replacing the clutch with a torque converter, as used by automatic cars.

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The unit sits out of the way under the fuel tank

It was combined with a two-speed gearbox that allowed the rider to select 'high' or 'low' ratio with a conventional foot pedal. It worked, but performance was blunted.

The new design has a similar set of controls (with a foot-operated gearshift but no clutch lever) but retains the same six-speed gearbox as the normal post-2014 CB1100 to ensure there’s no loss of performance.

It’s allied to a clutch that uses a computer-controlled, electro-hydraulic actuator, mounted just above the engine, instead of a bar-mounted lever. The clutch reservoir is conventionally mounted on the bars to make checking and filling easy. An array of inputs including sensors for speed, revs, gear position and throttle position are allied to a sensor that monitors pressure on the gear lever.

Using this info the ECU can cut the ignition during upshifts, blip the throttle on downshifts and modulate the clutch when starting and stopping. It’s basically the same as a modern up-and-down quick-shifter, but with an automated clutch.

Unlike a normal clutch the automated design defaults to a 'disengaged' position so if there’s a loss of hydraulic pressure or an electronic failure, drive will be disconnected.

A solenoid-operated valve closes the hydraulic system once the clutch is engaged during normal use to save the actuator from having to constantly maintain hydraulic pressure. Although the system is shown on a CB1100, its simplicity means that virtually any modern bike could be adapted to use a similar setup.

The actuator operates on a standard clutch

Clutchless Honda CB1100 explored:

  • Get moving Just like the original, the tech has the power to make bikes scooter-simple but with motorcycle performance
  • Easy peasy Unlike DCT the system doesn’t require reengineering of the gearbox, so it could be fitted to almost any model
  • Cheap as chips By avoiding the extra work associated with DCT, the system should be a lot cheaper – possibly just an option in the catalogue
  • Lots of go Combining the system with modern electronics means it shouldn’t blunt performance, unlike the old Hondamatic
  • The time is now As people across the world look for alternative transport, we imagine Honda will want to get this system out very soon

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Ben Purvis

By Ben Purvis