Need help changing rear shock spring

I'm thinking about changing the rear shock spring on my 2000 WR400.

Not sure what the stock spring is rated at. :applause:

I'm 205 pounds without gear.

I like the way it feels where I ride lots of rocks, roots, ect.., soaks it up pretty good, not a lot of deflection.

But when I need it most feels like it's bottoming out.

I only do Woods, trail riding, no tracks.

Fast tight technical woods riding, lots of rocks.

Will putting a heavier sping on it, make it harsher?

What spring weight should I use?

Any help appreciated.

Try the Race Tech website. It will tell you what you need. :applause:

Yamaha WR400F - I recently put a heavier spring on my 426 and loved it in the wide open desert. BUT when I go trail riding it is too stiff and I'm too lazy to back the pre-load off. So if you are only doing woods and trials I would not change the spring. I too am around 200lbs and went to a Race tech 5.2kg spring. My $0.02

I really appreciate that.

Thats my big fear, change the spring, all that work, and then not like it.



It is nothing to change your spring. You only really need a spring compressor.

It is just another opportunity to lube up all the linkage bearings.

I am about 225 without gear. Have the stock rear spring, with the correct sag adjusted, and in most cases I like the plushness of it on the tight stuff. i do not ride in areas where there are enough wide opens to get it beyond 50-60mph, so I have not really had any bottoming issues. Like you my concern is going to s stiffer spring may help in the lesser cases at higher speeds, but will diminish the ride in the more common tight twisties.

Im the same weight and had a racetech 5.6 installed in the rear of my 05 wr450, lovely! stock was a 4.8 and useless. Was mentioned above, the racetech website allows you to key in your bike / weight details and they tell you the recommended spring rate.

You should consider revalving both the forks and the shock if you are riding mostly tighter technical trails. You also need to check both the static and "race" sag of the rear shock as this is the only way of telling if the spring rate is truely correct for your weight. The revalving will make both ends of the bike way more complient in the rocks and roots and make for a much less tiring ride at the end of the day.

There are many articles both on this forum and other sites but basically once you have the static sag set (usually around 100 mm) there should be a 5mm difference between the bike under its own weight without rider and all weight removed. This is referred to as the "race sag". Hopefully that makes some sense to you.

Willy Fitz

I'm about 250 naked and just changed to a racetech 6.4 on my 03 wr450. I haven't trail tested it yet (hope to this weekend), but now I can get my race sag and free sag set properly where before I would lose half my travel just sitting on it. You can always soften your compression and stiffen your rebound to make it plush. Check the race tech site, however, I've heard they rate things a bit low.

Believe me if I had the money to revalve I would.

My buddy was over last year and we set the static sag.

I'll have to check the race stag though.

I just thought my being 45 pounds over the stock spring rate, plus the spring being 5 years old.(original owner). I'm putting a beaten on it.

Just don't want to end up with a lot of deflection in rocks.

I live in coal country!!

Lots of great mountain riding though.

Thanks for the help


I got my 5.6 spring on Ebay for $1.00!!!!!

Now I just have to find the time to change it.

And start from ground zero on my settings.


I'm 240 w/o gear. Per Ractech I need 5.74 for the riding I do. Found a 5.7 on Ebay. So, re-valving might be required to keep the bike plush on the trails? I'm not real happy with the suspension right now, seems like every body elses bikes feel nicer (it's a YZ I know). What's it usually cost to have the suspension done by a good shop? I don't think I'd trust any of the local bike shops to do it.


If you put the correct rate spring for your weight on the bike and set the sag up correctly(static and race) it won't feel harsh just more progressive. A too soft spring that you force by setting the preload high will blow through the travel quickly and bottom. A correct spring will be soft at the beginning of the stroke and get firmer toward the end of the stroke. Just what you want plush with decent bottoming resistance. :applause:



I got the spring just need the time to tear it apart.

Thats exactly whats happening to the shock, small short jumps, and I'm bottoming out.

Definately need to correct this.


Just thought I'd drop my 2 cents in here also. I'm 240 without gear, I run a 5.4 and have never bottomed. I ride an 03 WR450. I run 90% trails and mess around on the track a little, even when hitting the jumps on the track (granted I'm not hitting anything big), my big but coming down hard has never bottomed this bike.

I had my forks, and shock adjusted by someone who knew what he was doing!!

Not me.

I had my seals redone, and the shop had my clickers out of wack.

Not even on either side, top or bottom!!

Now if I can just get the time to change the shock!!

Do I need a spring compressor for this?

If you weigh over 185, you need a stiffer spring. At 205 your gonna need to be some where around a 5.8-6.0 Do a search "spring" and find some guys at your weight and PM them and see how they like the spring they purchased. Give "shockdoc" a pm, he seems to know a lot. Also might consider raising the fork tubes through the clamps about 5 mm.

I had my forks, and shock adjusted by someone who knew what he was doing!!

Not me.

I had my seals redone, and the shop had my clickers out of wack.

Not even on either side, top or bottom!!

Now if I can just get the time to change the shock!!

Do I need a spring compressor for this?

Do you need a spring compressor? YES!!!!

unless you have 4 hands and can squeeze 5.5kg - 6kg / mm, you need a spring compressor.

I have changed my spring and it was easy to do so. just get a compressor from an auto shop but watch out for clamps that are too wide as car springs have a heap greater circumference than bikes.

I suggest you get your suspension set up properly and valved by a shop and don't do it your self. If you don't, you will be kicking your self later.

I'll have to disagree with Matty on this one. I changed the spring on my 03 wr450 without a spring compresser and with no problems. Just back off the pre-load nuts. It's easy to do if you back off the lock nut and then twist the spring itself, the pre-load nut will follow. the spring will be loose before the nut gets to the top of the shock. Then just take off the bottom spacer (it's got a slot in it) and the rest of the spacers will slide off the bottom. Of course, the WR400 shock could be different, I don't know.

twisting the spring did stuff all for me...........

Job is just a million times easier with spring compressor. Just try belting your preload nut with a 6.0 spring in it. Not fun at all.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now