Hmm. TBH, if you have enough wire to braid, you'd probably be better off simply shortening them. Less wire = less EMF. Depending on exactly where the noise is coming in, you can also try the following:
- Use a ferrite ring on the throttle cable. A couple turns should suffice.
- Use a 1000uf+ ~10v capacitor on an unused receiver port.
- Relocating the receiver/antenna as far from the motor wires as possible.
- Upgrading to 2.4
If a new system is a bit out of your price range, troll around here because people are always selling their older generation DX2/3/2.0/3.0 Spektrum systems.
As far as a braided coating, before you go out and buy something, you could try wrapping a layer of aluminum foil around the three wires and see if that helps. If it does, get some nicer/better actual braiding. If not, at least you didn't waste your money. Just be sure there are NO exposed wires/connections that could short against the motor wires.