Hi,
Iv'e seen the Rickman gear shift conversion linkage kit , fitted to a Jawa Metisse, I think Edgar Phipps has it now, but the neatest conversion Iv'e seen was on an Historic roadracer, AMC/Norton gearbox using a Mitsubishi Magna gearshift cable (push/pull cable), running in a smooth arc above the swing arm pivot, from the shift lever at the gearbox, to a fabricated bracket on the left side footpeg .
cheers