This is a fool proof way to replace your cables (Inners and outers)
Don't mess around with electrical tape, duct tape, Gorilla tape etc.
1) Get a roll of 20-22 gauge steel wire (Any hardware store)
2) Cut a piece of the wire Twice the length of the cable + 1 foot on each end (just to be safe)
3) Pull the inner cable out of the outer sleeve while the outer sleeve is still in place on the scooter.
4) Feed the steel wire through the OLD cable outer.
5) Remove the inner cable from the NEW cable. (set aside)
6) Slide the NEW cable outer over the remainder of the steel wire (the 1st 1/2 of the length of wire has already been fed through the OLD cable outer.
7) With the steel wire running through both the new and old cable outers, simply pull the OLD outer while pushing the NEW outer with your other hand. (you can tie a knot in the steel wire, but it's really not necessary) The steel wire will guide the path for the NEW cable outer and Wha-la! Your new outer will be in place.

Pull the steel wire out from both outers. (toss the old outer, and save the steel wire for your other cables) (then save it for another day)
9) Feed the NEW cable INNER through the NEW outer!
DONE!
This method really is fool proof!.... and when it's this easy, it's actually fun!
* For the rear brake cable outer (since it dead-ends inside the frame tunnel, I simply pull the old outer off (leaving the old inner to slide the new outer onto), clip any frayed end off the old inner, and slide the new outer into place... then pull the OLD inner out from the Pedal side and slide the new inner in.
As I'm pushing the NEW inners in (from the headset) and pulling the OLD outers out from the bottom (engine side)
You can tie a knot.. but it's not necessary.. jut leave an extra foot of wire at either end and it's all good.
I pull both gear cables at the same time.
Wire runs through the OLD outer and NEW outer (inners have been removed) (OLD outer is still in place in the scooter)
Steel wire into OLD outer
Any hardware store should have wire