Springs. Thats it. Could change oil if you want to but dont have to. Could revalve if want to but sont have t0. Nobrakes did a great writeup.

 

thanks KLXer

 

The KLX250S and the KLX300R are almost exactly alike they only real difference is the street stuff and an electric strater. good luck. you can go to race tech and they will fit you with the right spring weight.

 

If you do anything with the front suspension change the oil as well. If you go to a suspension tuner they can change the suspension to make it shorter without changing the links and therefore maintaining the the ratio and preventing the tyre hitting the guard (bottoming out).
When I use my 17" rims I run the stock links. I only use the 1" lowering links with the stock wheels, I found the 2" lowering links made the rear way to soft for my weight. If I were around 140lbs I'm sure they would be fine riding solo. I would not double with them. If you are going to uselowering links with the 17" rims you will have to shorten the side stand.
Cheers

 

Re Racetech:---just a note that 300R springs are shorter than 250S springs.