I don't know if anybody here is familiar with cz dirt bikes but I have a couple and you only have to use the clutch to take off. It will shift without clutching in between gears. For this guy with this much dedication to still ride I would send my cz engine to a builder if the builder was will to look and see if they would be willing to attempt to modify the bottom end. With the clutch attached to the foot pedal he could just use it to take off and not have to worry about clutching between gears.