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Yz250f Shock? Fitment

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I am trying to change the rear spring on my 08 yz 250 2 stroke... I found a shock online from an 11 yz250f with the spring i need. My question is would that whole shock fit on my yz? It looks the same but i havnt been able to do a side to side. Also if it would mount where would the valving be in relation to a stock 2 stroke shock?

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Thanks monk... How about a wr450 shock? The spring rate on a wr is very close to what i need. I have an 07 available and i plan to put it on my 08 yz instead of the yzf shock i was looking at. The wr is much cheaper and im thinking the valving may be a little more plush than a yzf

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I don't think the WR shock is SSS stuff...

What I have read, the trick is to run the 16mm shock shaft in the SSS body... That's something I'll be looking to do next...

Edited by Monk

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I don't think the WR shock is SSS stuff...

What I have read, the trick is to run the 16mm shock shaft in the SSS body... That's something I'll be looking to do next...

 

I thought SSS was just for forks ?

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Tell us more about SSS shocks.  What is the difference between an SSS and non SSS shock and which models/years have which ?    Which is better for woods riding ?

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Tell us more about SSS shocks. What is the difference between an SSS and non SSS shock and which models/years have which ? Which is better for woods riding ?

I have no idea. I thought SSS suspension was the speed sensitive shock too...I know they came with the larger 18mm shock shaft and titanium shock spring... I don't think the WRs did...

Edited by Monk

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Actaully i think your right about the wr spring. It doesnt look like a titanium spring in the picture. It looks like silver paint like they were on most of the bikes before the titanium springs came out.

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Still considering the four stroke shock swap... I still need to figure a few things out. What shock should i go with? The 250f is a 5.1 spring and the 450f is a 5.5. I've seen spring calculators that had me anywhere from 5.2 to 5.6. Im 190ish w/o gear and run an oversized 3.1 gallon fuel tank.

 

Also are they the same internals? Will i be able to get my shock serviced and install an equal spring to get the same feel so i have 2 shocks of almost identical setup?

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A new spring is probably cheaper than a whole shock, and then you can get whatever rate you want.

Might also be able to find just a used spring from a 250/450f and not need to buy a whole shock.

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Thought is to have 2 shocks ready to go. One on the bike and one on the shelf or Being rebuilt. Same thing i was trying to do with the forks but the set i bought had pro action valves and a different caliper mount

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If I remember remember right from experimenting with that idea a 2010+ shock will not fit your bike unless you switch the swing arm to the '10+ style.   Spring seat is down farther on the newer f shocks and hits the older style swing arm. 

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JS264... I wasnt sure on the fitment but luckily i noticed the spring seat was different from the pics. I wasnt sure if it would interfere or not.  Im looking for a 06-09 now.

 

Still trying to decide on the spring rate. 250's are 5.1 and the 450's are 5.5.

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I'm going to back track to a previous question... Will a WR shock work/fit my 08 2 stroke? Monk answered earlier and said he didnt think they were SSS like the yz in 08. What does this mean exactly?

 

I found an 06 Wr450 shock online for a great price and supposedly its in prefectly rideable condition which is what i need. I would like to find something i can use while my shock is off the bike for maintenance.

 

It has a race tech spring that uses the same number as the one i need for my yz and the shock body looks indentical. I havnt been able to find valve info but the spring, and shock bearing kits are def the same for both bikes. Plus, the price is only slightly over what a new race tech spring costs so it wouldnt be a total loss if I didnt like it.

 

Anybody have 06 WR450 shock specs? Or think this would work/not work?

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Ended up buying the 06 wr shock i mentioned. I only paid slightly over what a racetech spring would cost so i took a chance... I took much less spring preload to get anywhere near the right amount of sag (expected since its a much stiffer spring), and it seems like there is a problem with the rebound adjuster. I had to run it all the way out to get close to the right amount of rebound. Id actually probably like it a little faster but I have nothing left. It feels like it gets hard to turn after only a few clicks, ten maybe. I can probably keep going but i didnt want to push it. Other than that the test ride went pretty well. Felt much better in most cases with a spring that has the right rate and it doesnt bottom over small jumps and hard root and rock hits like the stock shock which is overdue for maintenance and undersprung for my weight. Felt much easier to keep momentum and actually made the forks seem to work better in some situations.

 

Questions are... Anyone have any ideas with whats wrong with the rebound adjuster? Anyone have stock valve specs? (06 WR450) What tools do i need to properly rebuild/revalve my stock shock? Other than the nitro charge are there any special procedures needed to do this?

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Funny that I have a WR (2012) and purchased an 07 YZ shock and you have a YZ and purchased a WR shock.

 

I don't know about your 06 WR shock, but my YZ and WR shocks are pretty much identical except for

 

- the WR bumper is diffferent

- the WR compression adjuster uses a different piston

- the shim stacks

- the YZ shock has an 18mm shaft versus the WR is 16mm.

- the YZ shock has a shraeder port, the WR shock uses the pin.

 

The bodies, piston, shaft, comp adjusters, washers, etc, are otherwise all the same.  Like you I paid less for my shock than what a spring would have cost, though the spring on my shock is too soft to be of use to me.

 

I have no idea where the SSS comes from on the shock.   Presumably my 07 shock isn't SSS and my WR shock is and I can't tell the difference.

 

Here is a parts catalog that covers shocks and forks.

http://www.technical-touch.com/fileadmin/sitecontent/pdf-files/KYB_GenuineParts_2013_lr.pdf

 

I used the Racetech suspension bible and a couple Youtube videos to figure out how to build mine.   I recharged it with 125PSI air.  I'll recharge it with nitrogen once I know its the final build.

 

Hope this helps.

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MLC, the 06  I have has a schraeder and the bumper seems to be the same but all the otehr things you mentioned are probably correct. The main thing i'm looking for is valve specs. I probably wont, but if i decidce to stick with the WR shock i may want to change valving a bit. Its probably a bit stiff for a smaller, lighter yz. I need to know i'm starting from stock stacks if i do this or at least know what stock stacks should be for comparison.

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MLC, the 06  I have has a schraeder and the bumper seems to be the same but all the otehr things you mentioned are probably correct. The main thing i'm looking for is valve specs. I probably wont, but if i decidce to stick with the WR shock i may want to change valving a bit. Its probably a bit stiff for a smaller, lighter yz. I need to know i'm starting from stock stacks if i do this or at least know what stock stacks should be for comparison.

 

I've ridden a steel frame WR (06 ?), an 08, an '11 and 3 2012s.  The 2012s have the best suspension, mainly due to the forks, but none of them are anything to write home about.  My friend calls them 2 wheel couches.  They are great trail bikes, better than many of the other trail bikes out there, but the valving in the shock is a compromise for the wide range of riders and terrain the bike might see.  I don't think there is any magic in the WR stacks, especially for woods.

 

If you are looking for the stacks, I listed the 2012 shock stack in my thread.  The prior years are probably similar, though a bit lighter.  If you compare the WR stacks to YZ stacks, you'll generally find them significantly heavier, whereas most woods stacks end up being lighter than YZ stacks.

 

I found it very helpful to take a couple known good woods stacks and scale them for the weight of me and my WR.  It seems to have landed me in a good starting place if nothing else.   Once you get comfortable with rebuilding a shock, its just a bit of an inconvenience to revalve a shock if you don't get it right the first time.  Restackor is a great tool for visualizing the changes you intend to make and there are several guys on this forum with lots of ideas and advice to steer you in the right direction.

 

I'm really happy that I purchased a spare shock to work with.   I suggest you tear apart your YZ shock to see what it had inside it for shims and start trying to figure out what you want from your revalve.

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