My kymco zing 125 wont start and there is oil on the spark plug when i take it out so is it the valves that are damaged or more likley the piston or rings

SOURCE: Replace regulator/rectifier with a different brand?

Not always necessary to change the regulator/rectifier. Check all connections to make sure they are clean, use a good contact cleaner and finish off with dielectric grease on your electrical connections.
When some bikes get a few years on them the connections get dirty. Check to see if there are any burned or discolored wires anywhere around the regulator. The FIX on some bikes is to cut the connector completely out and solder the wires together and either seal them with heat shrink of a good electrical tape. Loose or bad connections get hot. As long as the regulator and rectifier are working there is no need to replace them if the connections are good.
Ride Safely, Ed

SOURCE: wont start by kick start but will by pull start

it could be the gaskets around your carb are bad and leaking air if so its thinning your gas fumes with more air then what is needed inside your combustion chamber witch is causing your engine to stop running like that. best of luck