I didn't see the voltage regulator listed for a 2005 kx250. A voltage regulator is not a ignition componet. Elec. componet used for charging systems, or even some lighting kits require a regulator. Some voltage regulators are also rectifiers which allows them to change AC current to DC currecnt.
I think at this point your friend needs to order a service manual. Until then I would stop guessing at the wire connects, you can possibly damage some of the componets.