YZ 250 power valve spring

I recently bought a new YZ 250 and am finding it's a bit to much bike for me,

so i am wondering if you can change or swap the power valve spring so the power delivery is more like a four stroke, or like a ktm exc model.


I don't think anyone makes powervalve springs for the YZ.

A whole lot of it has to do with the port timing, but if you don't want to spring for porting try some of these:

-Retard your ignition timing

-Flywheel weight

-Gnarly or Platinum 2 pipe

what about a spring from the WR 2 strokes?

I think that the only spring that would affect anything is on the governer, down in the bottom end, and tinkering with that would just not be worthwhile.

In 03 I bought a brand new YZ250 as my first bike and it kicked my ass up and down the trails till I learned a few things. What helped me was practice (obviously), a G2 throttle cam system, and a gripper seat. I haven't yet installed a flywheel weight, but I have heard that a 13oz weight will make the YZ250 produce real smooth power. Steahly makes pretty much the standard for flywheel weights.

There was a company that made a set of three springs with different presures years ago,but i think they really didn't help for power in either way.

Iv'e tried making shims for preload to retard the action of the power valve,all it did was give it a 'dead' mid-range. with the same top end power.

I agree with everyone else..retard the ignition and use a Gnarly pipe. Worked great for mine..

I think what your going to want to look into instead of a powervalve spring is flywheel weights. Adding flywheel weights should help you out.

can you adjust it so it opens later in the rev range?

IMO a FWW is what your looking for if your looking for more of a "4 stroke like" power delivery.

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