Almost looks like there is a clip underneath the top that holds the cable guide/ tube in place. If you could remove that, I think the whole assembly tube, cable, and housing might go through the top, but when you got to the junction where the cable splits off to the oil pump, might be a problem there?
Another idea, cut the cable and splice it back together. Kart racing, there are some cool connectors that are quick connectors for throttle cables, so you could change out an engine quickly at track, probably way too much trouble for scooter. I still think best solution is probably buy new cable assembly, what we have on scooter is not made to be disassembled? Cheers