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Has anyone had any luck running a Race Tech Rebound Separator Valve in a woods only application?

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There was a somewhat recent post about this but it wasn't woods specific and the posts seemed to eventually stray off the subject (lol). So... I thought I would bring it up again.

Anyway, here's my story with one. I started with a stack that I KNEW would work for me with the stock nut on the shaft, removed a couple of face shims on the comp side because of less bleed, and added a few on the reb side because of the extra bleed. (If anybody wants specifics I'll post them). Test rode the bike. Added 2 more face shims on the reb. Test rode again. Much better. The reb ended up at 7 clicks out and probably could have went in further but I didn't want it to start affecting the comp damping (that feels pretty good at 14 out). I had a race in a few days so, running out of time, I left things there.

On the smoother sections of the track and whooped out areas (braking and accel bumps) it got really good traction and turned well. As soon as you got in the rocks and roots... not so much. After 2hrs of this I'm quite certain it's still kicking a little on reb.

I realize that more LS reb is needed but my big question is... If you've got to stiffen the LS reb that much and turn the adjuster in that far to get it to act like a "normal" shock... what's the big advantage? I feel as though I'm urinating into the wind here. I can see where one of these could work well on a motocross course, no so sure about the woods yet.

Has anyone gotten one tuned for the woods and is it worth the trouble?

Edited by James I

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What shock was this on ?

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Sorry mog. I really didn't give enough info there. 04 KX250

190 lb. C class (woods) 5.3 spring

These are my current stacks and settings with the reb separator valve installed.

Compression

(6) .20x40

.15x28

.20x40

.20x38

.20x36

.20x34

.20x32

.20x30

.25x28

.25x26

.25x24

.25x22

.25x20

Rebound

(8) .20x36

.10x28

.25x36

.25x34

.30x32

.30x30

.30x28

.30x26

.30x24

Compression adj - 14

Rebound adj. - 7

Also- looking at the build sheet, I've only added 3 face shims to the pre-sep valve stack. My first post of adding 4 is incorrect.

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why use a separator nut for woods?

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why use a separator nut for woods?

I'm asking myself that question too now. Basically, it was/is an experiment with something new (to me anyway). Sounds like you know more about them than I do. But, that's why I'm asking questions. Should I put the stock nut back on?

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If you're a taller guy it could help with pitching in slower speed stuff maybe.  It's definitely a setup that favors faster overall riding though, and it sounds like that's where you're seeing the benefit.

 

What's making you think you need more LSR?

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in the woods, unlike fast desert, you can use less lc. with that being said, you've got the 18mm shock shaft which softens the compression damping already. so, in my view; more bleed is your friend in a woods application. 

 

also, you don't need to go stupid stiff rebound damping. in other words, don't put a bunch of .30 face shims on the low speed rebound. my good buddy russ and i were just discussing the same scheme this morning. on my two smokers, i prefer a ridiculously soft comp stack in the woods. it really helps the rear end to stay planted; especially under throttle. just my opinion of course. but, the single-track that i ride makes this style of valving work for me.

 

i can deal with other parts of the tune not working quite as well in certain sections. however, it soaks up the trail junk, and technical rock sections easily on the gas. i make up more time as a result. 

i get "far out" when it comes to my bike (because it's me) but, i think of the technical nasty rock sections as if they were sx whoops; just slower speed, and not one line.

 

i get through easier with a soft shock, and more than a noodle for a  fork. i don't want my forks to blow through 1/2 the travel on a rock i could throw through someone's window. lol. 

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Isn't a 2.4mm bleed hardly doing anything different as std isn't much bigger ?

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Yes, with a bleedhole that big, the Sep Nut just does its job as a Sep Nut and does not add too much ls damping.

Sachs uses a reb checkvalve with a 2.5mm bleedhole too...

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James,

 

I just grabbed all your info posted and passed it over to our R&D team to see what they recommend.  I will keep you posted.

 

Thanks,

chris

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James,

 

I sent you a PM with our Head of R&D's cell number.  He wanted to walk you through his thinking/tuning with the RSV and see if he could help get you dialed in.

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c'mon! your post bombing this thread to sell this guy on rt. fawkin' bullshit! why not offer up a solution instead of advertising here? this is supposed to be a technical forum. well, maybe it was at one time....can't you offer up a solution to his valving scheme? or, do you have to get permission from rt? why don't you lend a "technical hand" instead of diverting to the "higher ups" in hopes that he's gonna go with gold valves. please tell me you are more tech savvy than just a gold valve installer. honestly, if your just posting for the sake of getting people on board the rt platform, I WILL FLAME YOU EVERY POST! if they chuck me; they chuck me. fawk awph!

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If you're a taller guy it could help with pitching in slower speed stuff maybe. It's definitely a setup that favors faster overall riding though, and it sounds like that's where you're seeing the benefit.

What's making you think you need more LSR?

I'm not all that tall (6'0") but my upper body does have quite an influence on how the bike handles at time. The RSV does seem to help with pitching. I also agree that the setup favors higher speeds. My only real problem with the way it handles is in the lower speed sections, especially sharp turns that have 2-3" rocks or roots. If it's an off-camber especially. It feels like the tire is returning to the ground with enough force to lose traction and slip. If there's a berm, no problem. That's why I was thinking more LS rebound damping would help. Edited by James I

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in the woods, unlike fast desert, you can use less lc. with that being said, you've got the 18mm shock shaft which softens the compression damping already. so, in my view; more bleed is your friend in a woods application.

also, you don't need to go stupid stiff rebound damping. in other words, don't put a bunch of .30 face shims on the low speed rebound. my good buddy russ and i were just discussing the same scheme this morning. on my two smokers, i prefer a ridiculously soft comp stack in the woods. it really helps the rear end to stay planted; especially under throttle. just my opinion of course. but, the single-track that i ride makes this style of valving work for me.

i can deal with other parts of the tune not working quite as well in certain sections. however, it soaks up the trail junk, and technical rock sections easily on the gas. i make up more time as a result.

i get "far out" when it comes to my bike (because it's me) but, i think of the technical nasty rock sections as if they were sx whoops; just slower speed, and not one line.

i get through easier with a soft shock, and more than a noodle for a fork. i don't want my forks to blow through 1/2 the travel on a rock i could throw through someone's window. lol.

My forks are plush but firm also. No noodles. I'm curious ... what sort of comp stack would you consider ridiculously soft?

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I'm also 6'0, and I notice a HUGE difference in pitching stability and my overall ability to just keep my weight centered with the separator valve.

 

Based on the event you described, I have a 50% feeling that you need LESS LSR.  I think these valves give a tiny bit more initial damping force in the rebound direction as well, especially if you aren't running the adjuster pretty far in.  I'd probably remove one face shim from your original rebound setting just for shiggles, and maybe beef up the HSR part of the stack if you're concerned about other highspeed/deep travel events.

 

How does it do with 10-12 clicks out on rebound?

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I think you need less low speed rebound.you need to get the rebound clicker farther out to handle offroad chop.you may need to stiffen the high speed rebound(shim stack) but you will need to test that.

 

I also think the rebound nut you have installed is doing nothing,the hole is too large.1.5 to 1.7 mm hole and then soften your comp stack .you soften the comp as much as you can as long as it is handling your highest speed sections.there can be huge differences in required comp stacks for bush,(rider position ,terrain,speed, rider weight). 

 

my wood comp stack is about 25% stiffer than a 2007 yz450 shock.(I,m fat and slow.)but this current stack is for stopping blow thru on high speed sections,it doesn,t work well in boulder fields.

 

I think the rebound nut could help my shock setup as it would give me back low speed comp(via tighter bleed) then I could try to soften the comp stack back to a more normal setting.

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mog and Vietze

The 2.4mm is the common bleed. I'm not sure how much bleed the rebound has. Under the check valve is several much larger holes. I wish that I had measured them before putting it together the last time. I'm curious what the damping curve would look like on Restackor. ImageUploadedByThumper Talk1400728889.205264.jpg

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My forks are plush but firm also. No noodles. I'm curious ... what sort of comp stack would you consider ridiculously soft?

 

well, ridiculously soft would be too many transition shims in the base valve, combined with a check plate for a mid; in the forks.

 

in the shock, i tend to leave the hsc alone. i would try something along the lines of all .30's in the hr stack. and, don't get carried away with too many face shims  on the lr. what is your shock spring rate? 

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