Honda introduces dual clutch gearbox

New transmission to debut on new Interceptor

By Motorcycle.Com Staff, Sep. 09, 2009
Honda had developed the first dual clutch transmission designed for large-displacement sportbikes.

The dual clutch transmission will be installed on a new large-displacement Interceptor due for North America and Europe in 2010.

According to Honda, the transmission features a light, compact design that can be adapted for use with existing engines with little modification.

The transmission runs in three operating modes, a six-speed manual mode as well as two fully automatic modes: D-mode for regular use and S-mode for sporty riding. The D-mode could be used to maximize fuel economy while the S-mode can be used for better performance through the power curve.

Honda's dual-clutch system uses one clutch for odd gears (red) and another for even gears (blue).

 The rider can switch between the two automatic modes when in gear, but not in neutral. Operating the shift switch while in an automatic mode will switch the transmission to manual. In either of the automatic modes, gear shifts are performed in response to riding conditions. In manual mode, the rider operates the shift switch as usual.

The dual clutch system uses two co-axial drive shafts, the internal shaft for the odd numbered gears and an external shaft for the even gears. Each drive shaft is connected to its own independent clutch.

Unlike conventional dual-clutch transmissions, Honda's system uses two in-line clutches and two coaxial shafts, one inside the other to make the system more compact.

When shifting from first to second, the computer-controlled system releases the even-numbered clutch and selects the second gear. The clutch for the odd-numbered gear then releases while the clutch for the even gear re-engages. The result, in theory, is a seamless gear change without interrupting power that Honda says will deliver precise acceleration control.

Dual clutch gearboxes have been used in race cars since the ’80s. For use in motorcycles, Honda needed to make the transmission more compact. The new system uses dual input shafts, a new in-line clutch design.

Honda has also developed a new automatic transmission system for the Cub.

The CV-Matic transmission is more compact than Honda’s existing automatic transmission systems. This was achieved by placing the CV-Matic’s pulleys closer together. Honda added a new cooling system developed from existing automatic transmission systems to keep the drive belt cool, enhancing its durability.

Air intake and exhaust ports on top of the CV-Matic's transmission case and a oil cooler on the right keep the drive belt cool.

Honda will use the CV-Matic on Cub-style scooters in southeast Asia in 2010.