KTM developing semi-automatic transmission for future big V-twin

KTM is already working on a touring ‘GT’ version of the 1290 Super Duke and a new patent application from the company suggests it could get the option of a semi-automatic transmission.

The patent application is specifically for a gearbox lock, which prevents the transmission from turning and essentially works as a parking brake. However, the document makes it clear that it’s intended to be used on a semi-automatic bike.

Specifically, the document says the lock is intended to be used on a bike with a centrifugal clutch, the sort you might normally find in a scooter, that automatically decouples the engine from the transmission at low revs. It also says that while the six gears inside the box are conventional, they’re intended to be engaged using an electric ‘shift motor.’

The idea of combining a conventional transmission with a centrifugal clutch isn’t new, and MV Agusta already offers bikes using the Rekluse centrifugal clutch that, allied to an up/down quickshifter, mean there’s no need to use the clutch lever at all. KTM appears to be working on a similar idea but with the addition of electronic shifting, whether by foot lever or push button, to allow seamless integration of the gearshift and engine management and allow for the smoothest possible gear changes.

The locking system shown in the patent is needed because, with a centrifugal clutch that’s naturally disengaged when the engine is stopped, there’s no way to leave a bike parked in gear.

KTM has added a simple pawl to the mechanism that engages a claw into the teeth of one of the gears on the input shaft, locking the transmission. The pawl slides into place when a ‘park’ position is selected on the shift drum.

The patent explains: Control commands from a motorcyclist can be received by the electronic control unit so that the motorcyclist can shift between different rotational positions of the gearshift cylinder, in particular between at least one rotational position in the freewheeling range, and a rotational position in the locking range, and/or between rotational positions in the freewheeling range. This allows a motorcyclist to operate the automatic gearbox and the gearshift lock. The gearshift lock can therefore be operated via existing components if there is an automatic gearbox on the motorcycle, and no additional components are required.

How do we know that the semi-automatic transmission is aimed at the firm’s range of ‘1290’ models using the 1301cc version of the LC8 V-twin? Because the drawings are so detailed that even some part numbers are visible, including on the input shaft and on 1st gear’s idler. Cross-checking those numbers against KTM’s parts database confirms they’re components used on the 1290 Super Duke R, 1290 Adventure and Brabus 1300 R models, which all share the same 1301cc engine.

With up to 180hp on tap, a semi-automatic bike using the big LC8 V-twin would surely be the most powerful production model yet to use a centrifugal clutch and semi-auto transmission.

The pictures also show the shift motor (numbered ‘27’) that rotates the shift drum, allowing pushbutton control, although the document says that a conventional, foot-operated shift could be used instead.