My bike cannot control the rebound of the stiffer installed springs. Rides like "all springs". Since there is no adjustment I'm going to try thicker oil. Wanted to see if anyone had tried some different weights before going into different valving.

 

Just add 10 cc to each leg first. (quick fix) It'll affect the compression too though.
Should make a difference.

Don't forget to bleed the air from the forks regularly, as the pent up pressure doesn't help.

 

I haven't tried thicker oil but that's what I would do if I was in your situation.
Thicker oil will slow things down a bit.
Good luck and be sure to post your results.
But, as Woz said, it will affect compression as well which may cause other issues.

 

You are pretty much stuck with the factory rebound valving. Access to the rebound shims and valve is by way of a crimp. That's one good reason to switch to 1991-1995 KX forks.

Ride on
Brewster