Heavy guy needing shim stack recommendation

I am needing some help with my suspension setup......

06 YZ 450

250lbs with gear

Ride mostly mx - I'd hit the bigger jumps if I trusted the suspension

I have the recommended springs front and rear .52 and 6.2

I had planned on playing with oil weight and volume instead of messing with the valving mainly because I don't have the money to spend on gold valves for both ends.

But, if someone can help me with correct valving shim stacks for both rebound and compression I can do the work. I just don't want to go in blind....


The best advice you can get here is to call Dave Johnson of Smart Performance.

I probably have some info around here somewhere. Give me a day or so...

Just a question - how do you know you have the correct springs. Did you actually measure sag - race and static or did you look at a site like race tech?


Those are the recommended rates directly from race tech

Those are the recommended rates directly from race tech

so probably wrong.measure your sag front and rear.

I can adjust sag to be anything I want by adjusting preload.....

Based on my weight/riding style those are the correct springs.

Please list your rider and static sags front and rear

Can't. It's completely torn down for suspension rebuild.

So, all of my suspension is off and cleaned laying on the bench for me to reassemble it. I have been looking at the valves and stacks and it looks as if the peening has already been ground off.... So, I'm gonna assume the previous owner messed with the stacks or had them worked on. That includes the shock as well..... No peening seen.....

Anyway, I still really haven't gotten any useful info regarding shim stack recommendation that I'm asking for....

I'm thinking from all I've read that with heavier spring rates I'm going to need less compression dampening and more rebound dampening to help resist the pogo effect.....

I would like to know if I can shuffle my stacks around for this effect OR am I better off just getting race tech stuff with recommended setup from them.....

post your stacks

The race tech spring calculator seems to suggest softer springs then would normally be I dictated. I believe this is due to how they set up bikes with more compression dampening.

I would post your stacks and then tell us what your feeling when you ride the bike. There are some pretty talented guys on this site. If you get no response.

Call Dave Johnson at Smart Performance I know he can help you.

I'll have to go get a new set of calipers to do that......

My son ruined the last set....

I am probably going to go to the highest spring rate racetech has at .54 forks and 6.4 rear. It's torn down so I haven't and won't have a chance to ride it until I get it back together. That said, I know I'm going to need to provide some rider feedback with the new springs in place. But, is there a starting point as far as shim stacks go for ballpark and give feedback for changes after I ride it?

Cause with the setup I had with stock springs I would bottom out so bad that I stopped jumping the long tabletops at the track cause if I shorted the jump I thought I was gonna wad it up. I know that I'm just too heavy for the springs.....

And it's keeping me from riding as aggressively as I would like.

stock stacks everywhere except rebound on shock.the stock stacks can be found here via search or on valving logic.


shock rebound ,replace the 36x.15 shims with 10 36x.20 shims.leave the rest alone.test and come back with your dislikes.


also drill the comp adjuster to 2.7 mm if it is the smaller (2mm ) size.there are 6 holes.


the fork plastic free piston should also be drilled to prevent it cracking.search on here and you will find detailed posts on how to drill it and how to bleed the forks properly.

I've read about the free piston.... Think I might upgrade to the aluminum pieces from one of the vendors I've read sell them.

I'm not sure I understand the drilling of the compression adjuster holes.... Shock or fork?

Could you post a pic?

Also, where can I buy shims?


That helps a lot with a starting point and will save me several hundred $$$ if I can get it where I want with stock stuff

Checked out the valving logic site. They don't have 06 yz450 info but they do have 07 listed and I'm guessing they're the same.

This is from valving logic:

Stock 07 YZ450

shock comp

6 - 40.2


30.15 s










22.3 b

41.4 x 4.5 w

shock reb

10 - 36.15

28.1 s







24.3 b

2 - 26.4 f

26 x 3 w

What I have:

06 YZ450


























Top nut


Keep in mind I don't have calipers to give exact thickness but I went off feel and comparison to what I had in my hands

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