04 yz250 rear shock options

[yz250474]

My shock needs fully rebuilt... so I'm going to buy a used one, its a lot more yz250f shocks on there. it seems like I read a thread about 250f and 450f shocks on a yz250.. what year yz250 shock will work.. and if the 250fs and 450s can work what all do I need and what years can I use?

Edited August 8, 2014 by yz250474

[arnego2]

I hope you are aware that many of the used shocks from aution sites need also a rebuild? Or at least oil changes and nitrogen recharges.

 

If that is not a problem you can used the bottom part of your shock on the 450f or 250f shocks if they are longer or smaller to get the same lengths.

[yz250474]

I hope you are aware that many of the used shocks from aution sites need also a rebuild? Or at least oil changes and nitrogen recharges.

 

If that is not a problem you can used the bottom part of your shock on the 450f or 250f shocks if they are longer or smaller to get the same lengths.

I just wanted one that didn't leak, I ordered this one off a 06 yz250f . he says its in good shape and don't leak. I plan on having the forks and shock rebuilt for me, but it will probably be a few monthhs.

I got the shock for $109

[numroe]

Leaking is often a sign of neglect. The leak is nothing IF it's just a worn seal.

 

What you should really care about is the condition of the bore surface inside the shock body, and the condition of the chrome surface on the shaft.

 

So maybe your 2004 shock simply needs a rebuild kit.  Aftermarket rebuild kits including head/seal assembly and bladder, work great and cost under $100. Add fresh oil and it's like new again.

 

In the end you want a good handling shock.  Stock 2004 valving was pretty good. For intermediate pace and body weight on rough MX tracks, it was too firm on comp dampening, and for any purpose I think it was too fast on mid-speed rebound.   Stock 2006 to 2007 and maybe 08 was a jack hammering mess.

 

Personally I don't like the 18mm shaft in the 2006+ 2 stroke bikes. I prefer the 16mm shaft. As used in the 2004 shock, and as now also back in the current YZF 4 strokes.

 

What is your weight and intended type of riding and pace?  I could probably tell you some valving stacks that you might like. Not too far from stock.

Edited August 9, 2014 by numroe

[yz250474]

I'm right at 140lbs... I'm mostly going to be trail riding for now, but I really want to take it to the local mx track. so really I want to set it up for mx.

[numroe]

Then you'll probably hate that 2006 shock. I suppose it depends on what you are used to.

[arnego2]

Wouldn't it be possible to run his 2004 shock internals in the 2006 shock, sure using the seal of the 2006 shock if that seal is OK?

Edited August 9, 2014 by arnego2

[yz250474]

Then you'll probably hate that 2006 shock. I suppose it depends on what you are used to.

Why do you think I will hate it?

[MANIAC998]

   Stock 2006 to 2007 and maybe 08 was a jack hammering mess.

He already told you why he thought you were going to hate that shock.

[numroe]

In my opinion, a 2006 YZ250F shock will be too harsh for a 140 lbs rider who also wants to ride some trails, and is learning MX.

 

Wouldn't it be possible to run his 2004 shock internals in the 2006 shock, using the seal of the 2006 shock if that seal is OK?

 

Yes, almost.  But you would not need any seal off the 18mm 2006 shock.  Only reusing the 2006 body+res with its compression adjuster.

 

If the inside of the 2006 body is not showing signs of wear, then a very good hybrid shock could be had by putting the 2004 16mm shaft assembly into the 2006 body and using a softer spring off a YZ125, and some suitable shim stack valving.  Plus the 2006 bladder and the 2004 seals and piston ring should be replaced, which are cheap to buy.

 

With the shim stacks, for a light weight novice to intermediate pace rider, I believe a zero cost huge improvement could be had by:

 

1. Comp stack: A smaller clamp shim. Just move the smallest 21mm clamp shim from the top of the rebound stack (not needed there) to be relocated between the existing 23mm comp stack clamp and 24.0mm shims.  So the old 23mm clamp is effectively just a spacer to maintain overall stack height, and the 21 becomes the new clamp.

2. Comp stack:  Move half of the .25mm thick shims to be relocated under the small clamp shim at the bottom.  Softening the comp stack for mid and high speed impacts, while keeping the exact same overall height.

3. Rebound stack: Done.  Change 1 gave it a bigger clamp shim, so it is now slower on big fast rebound strokes. I would also add two more 36.2 reb face shims - if they were available.

Edited August 11, 2014 by numroe

[arnego2]

+1000000 thx great info ?

[numroe]

You're welcome.

 

On my 2004, I have such a hybrid shock. That is with the older 16mm shaft and the newer body with larger res. Using my own shim stack tweaks and a Race Tech RSV nut (1.5mm bleed).  It works very well for me ... substantially better than a stock 2004, 2007 or 2010 2 stroke shock.   I also have the enlarged the ports on the comp adjuster piston from 2.7 to 3.0mm but I did that for the 18mm shaft and maybe those larger port do very little to allow flow of oil to the res with the smaller 16mm shaft.   For me on my 2004 YZ250, the RSV works as advertised.  The above shim stack mods I suggested because he won't need to buy more shims. Just reshuffling.

[yz250474]

You're welcome.

On my 2004, I have such a hybrid shock. That is with the older 16mm shaft and the newer body with larger res. Using my own shim stack tweaks and a Race Tech RSV nut (1.5mm bleed). It works very well for me ... substantially better than a stock 2004, 2007 or 2010 2 stroke shock. I also have the enlarged the ports on the comp adjuster piston from 2.7 to 3.0mm but I did that for the 18mm shaft and maybe those larger port do very little to allow flow of oil to the res with the smaller 16mm shaft. For me on my 2004 YZ250, the RSV works as advertised. The above shim stack mods I suggested because he won't need to buy more shims. Just reshuffling.

What kind of riding do you do? and how much do you weigh?

I rode today a little.. it was just to muddy. but I could not keep the front wheel on the ground, I was just wondering if and how a worn shock could cause that? or if race sag to low or high could cause it?

Edited August 11, 2014 by yz250474

[yz250474]

Well I got the 2006 yz250f shock today and I was disappointed. the threads for the spring was dinged all up and bearings falling apart. so I'm going to see about sending it back. if I used my debit carb thru paypal how will I get my money back? will it be put back on the card? (First time I've had to send something back)

Edited August 11, 2014 by yz250474

[arnego2]

Understanding but you could use the Info of numroe and use the reusing your 2004 body+rest with its compression adjuster and the seal of the 2006 piston and shaft.

[yz250474]

Understanding but you could use the Info of numroe and use the reusing your 2004 body+rest with its compression adjuster and the seal of the 2006 piston and shaft.

I was planning on looking into his suggestions, but I bought this shock thinking it was in usable condition, which it is not. I only bought it to get some time on the bike, the way it is I'm better off with the shock I already have on the bike.

Also I've talked to a guy that rebuilds shocks on raptorforum... everyone is happy with his work and I know when he gets done they look like new at a low price... so if I can get my money back I'm going to send him my 04 shock... I knew I should of did it in the first place. its my first dirtbike and I'm learning to ride so I'm not looking for the best suspension, just rideable.

Edited August 12, 2014 by yz250474

[yz250474]

Idk I might just keep it and have it built for my weight.. what do you guys think? $109 for it.

[numroe]

Idk I might just keep it and have it built for my weight.. what do you guys think? $109 for it.

Don't bother.  Send both the 2004 and 2006 shock to that suspension guy you trust, and ask him to use the 2004 internals with the 2006 body+res+comp adjuster, and a spring to match your weight. Plus of course some valving mods for your weight and needs.

 

If the inside of the 2006 body is not worn out, then $109 for the body and comp adjuster is a good buy. Plus you got a Ti spring for free! Bummer that 250F rear spring will be too stiff for your needs, but you could sell the spring for at least $80. I'd guess it's about 5.1 Kg/mm. At 140 lbs on a YZ250 something like 4.7 sounds about right for you.

 

Compared to the stock 2004 shim stacks, I think you'll be way happier if you get him to soften the comp stack (eg. change all the 0.25 thick shims with 0.20) and firm the rebound mid speed just a little (by adding one 0.20 thick 36mm face shim).

[numroe]

but I bought this shock thinking it was in usable condition, which it is not.

Any time you buy a used shock, if the outside doesn't look near new or effectively unused, then at a minimum it needs fresh oil and re-greased end bearings.  eg. Some used shock might looks awesome except for a tiny chip on the spring or alum, then it should still be opened up. I cannot overstate how much better they work with fresh oil.

 

FYI: After the shock is removed from the bike and cleaned, the time needed to re oil and gas a shock is about 30 mins for anyone who has done it a few times and has the right tools. Add another 20 mins to re-valve the main stacks. I can do mine in about 40+30 mins, and I'm slow at mechanical work. I enjoy doing it.

Edited August 13, 2014 by numroe

[yz250474]

Any time you buy a used shock, if the outside doesn't look near new or effectively unused, then at a minimum it needs fresh oil and re-greased end bearings.  eg. Some used shock might looks awesome except for a tiny chip on the spring or alum, then it should still be opened up. I cannot overstate how much better they work with fresh oil.

 

FYI: After the shock is removed from the bike and cleaned, the time needed to re oil and gas a shock is about 30 mins for anyone who has done it a few times and has the right tools. Add another 20 mins to re-valve the main stacks. I can do mine in about 40+30 mins, and I'm slow at mechanical work. I enjoy doing it.

Thanks, I decided I'm going to keep the shock. I got the old bearing out I'm waiting on the new one to get here. I watched a few videos on rebuilding the shock. I plan on riding the bike atleast a few hours, then ill talk to the guy about rebuilding it. heck I may try rebuilding it myself.