2000 ktm 250 EXC PV

about the cdi i really don´t know but the PV thing, yes the bike have it.
on the right side of engine, below the water pump cover there is a small cover held with 2 M6 screws, there´s is the spring.
simply, the more preload more rpm the engine has to turn to overcome the preload so, later on the rpm range the valve opens. less load on the spring and sooner the hit comes.

laid the bike to left side or oil will come out.

I know the '00 300 had an adjustable spring. Not 100% sure about the 250.

On the 300, it's a personal preference thing. I know I've never even contemplated adjusting my '02 250 as this motor shreds and suits me fine just how it is.

I know several guys with '99 - '00 300's. The woods riders often prefer to have the powervalve open later and will adjust the PV spring to do so. The 300 has plenty of grunt in the woods without the PV opening too soon.

When it opens later, the bike (the 300, anyways) tends to get better fuel mileage and you don't have to worry about a low/mid hit in power as you are picking your way through technical terrain. Rest assured, 100% of peak power is available when you get on a fire road and go wide open.

I know newer models have 2 map settings not sure about your model. A riding buddy of mine has an 07 I think. It did not come with a switch to change maps you had plug and unplug the wires for 1 map or the other. He bought a rocker switch from a gas gas dealer and mounted to the handle bar. The other map setting is supposed to be for muddy/slick conditions. Its like riding with the choke on.