Front fork springs
 

It appears as though one easy update for the KLX250s is to replace the springs. Spring selection is a function of rider weight, and installing them looks very straight forward. Question is: where to get them??

For '09 and later models, Moto Pro seems to be a reliable source.

Or Racetech. It seems Moto Pro and Racetech are the best sources, plus I think both have 'calculators' on their websites to calculate what the best spring for your weight/experience/riding type will be.

Are you sure RT has optional fork springs? The reason I ask is that their site doesn't show any alternate springs. They list a recommendation as far as the weight of the spring, but they show no alternate choices...kind of strange. If you check for rear springs, they show several alternates. I'm just curious. I used RT fork springs, but I have an '06 which will use KLX300 with no problem. I know for sure that John at Moto Pro has '09 and later fork springs, with alternate weights.

If you open up the forks, you will want to change the shims for the oil. That is the big fix.

+1^^^
If you are doing any 'enthusiastic' off roading then adding new valving makes the biggest difference in control.

Tell me more! I'm mostly unfamiliar with working on suspension. I watched a video on how to change the springs and it looks very straight forward. No idea about shims and valves and such.

The damping in the KLX fork is pretty far off the mark for most riders. Going to a Moto Pro or Race Tech Gold Valve setup with a new compression piston and valve stack make a ton of difference in fork performance.

When I tap the front brakes, the nose dives, so I'm on board. Is changing the valves a DIY? Are there how-to videos? Links appreciated.

A quick search of "fork revalve" yields several results like this.

KLX 250S - Kawasaki Forums[aus]-diy-shock-fork-revalve-service-42209/