Can I move shims from compression stack to the rebound stack to increase rebound?

[CMJ]

Hi All-
I think I'm finally to the point where I'm ready for heavier springs. My last desert ride felt very choppy at slightly higher speeds than I usually ride in the rocky areas. After that ride I did two days at an MX track for practice, and blew out my forks. I was bottoming out everywhere, and now my knee is killing me.

I ordered .42kg springs, hopefully they are not too stiff. I'm 200lbs without gear, but I ride slow rocky stuff and also desert.

Now to the real question, I searched and have not found ANY information regarding this. I'm going to remove at least 2 shims from the valve stack, would moving those two shims to the piston stack increase rebound a little? I can't seem to find any info on people modifying the stack on the damper rod. I have not pulled them apart, but they look like they are the same size.

20210802_105511.jpg (902.57 KiB) Viewed 2081 times

[KDXGarage]

You are wanting to put in stiffer springs and also reduce damping less than stock?? Any interest to just go with the increased rebound of the stiffer springs before removing rebound shims?

I am thinking you are VERY safe on 0.42 not being too stiff at your weight.

Get a really fine pick and separate out the rebound shims. There are very few there. Removing just one would make a big change.

If you want to remove two from the compression base valve, then several people have done that to lessen compression on high speed hits. READ UP ON FILING THE THREADS BEFORE REMOVING THE NUT.

Keep searching until you find at least two threads where people cranked on the steel nut on the aluminum shaft that is peened over the nut. A heavy hand and a steel nut almost always wins against aluminum.

[CMJ]

What I want to do is take the two shims I remove from the compression stack and add them to the rebound stack. I figured adding two additional shims to the rebound stack would increase rebound, to help better control the stiffer springs?

[KDXGarage]

Sorry to not understand. Just be careful on the threads and file them all. Measure the number of shims and thickness on rebound. I can't remember if I ever had a 1995+ rebound piston off before. I don't know the dimensions on the shims. I know a KDX250 had a mix of 0.10 and 0.15 mm shims, as best I remember.

[MoonStomper]

If you want better control, contact Travis at Go Race Suspension, Blacksburg, VA. He does a Belgian Valve conversion that is a little different from the Race Tech Gold Valve that will give you the feel you are looking for. He’s an expert on these old forks and he’s made my KDX a very competitive hare scramble racer. The difference in feel and control is astonishing.

[CMJ]

I ended up leaving the rebound stack alone for now. The .42 Racetech springs seem to be much better than stock. I was afraid they were going to be too stiff. I've only had one ride on the new setup, and it was in slower rocky single track. The front end rides higher, and it seems more compliant on the smaller 3-4" sharp edge rocks and bumps. I can't wait to get it out in the desert and see how it handles the whoops.

[KDXGarage]

Good job! The too soft springs allowed the bike to ride lower, putting more weight into the front and putting it farther into the travel.