Changing fork oil, need a little help.

[JasonfromMN]

Yes, I put a crossover shim after the face shim the 1st try, then the crossover after the second large shim from the piston the 2nd try. Not much difference in feel, if anything worse.

I actually think I might need a bleed shim and to remove one shim in there somewhere. Maybe one of the larger shims or mid ones. I read that removing one of the smaller ones near the bottom will actually make it stiffer.

Anyway, doesn't matter. They went off to the tuner earlier this week. He called me when he had them apart to discuss what is going on. Said he'd def be able to change them. I told him I LOVED the forks on my 07 WRF so he kinda knows what Im after. Everyone seems to review them as too fluffy but man those things soaked up the junk to just about put you in a faster class. I have a 15' - 20' ramp jump that I cased a few times with the WRF and never bottomed not to mention when I hammered large whoops they never slammed the bars back at me either. That a perfect set of forks no? No bottoming, plush on junk and not kicking the bars back means good rebound. BTW he say's that year WRF had KYB "open chambers".

I missed his call tonight, I wanted to find out what he changed. Should get them back Sunday.

 

[ray_ray]

Sounds good on the forks .... I think we all get our forks to operate at our speed and this is what makes them great to us ...

As my forks have got better, I have increased speed.... And with speed increase, I can tell they need more of something to keep them plush at the higher speeds ... This is probably where a real tune job comes into play ...

Husky I believe have the open chamber and maybe sealed chamber KYBs .... Not 100% sure but I have been reading some on the forks lately and I see them different terms used to describe the forks ... I'm not sure why they stopped with the dual chambers ... I really like mine ...

I'll get into my stack again I think but not just yet ...

 

[JasonfromMN]

What will you do with the stack the next go around? Should get my forks back tomorrow! Can't wait.

 

[ray_ray]

I'm just gonna remove a couple shims from the compression stack as suggested from another thread ...

I rode about 30 miles on the trails yesterday in all kinds of stuff ... Forks worked very well ... The banging I was trying to get rid of now about 95% gone ... My speed has increased a great deal also ... Maybe the shim change will do more but I'm really not in a big hurry to try it ... Maybe n a couple of weeks ...

A short ride on the track showed me that the forks will bottom much easier with the lower oil amounts in the outer chambers ...

Let us know how the new forks worked!

update: I removed another 20ML from my outers tonight and will test ride 1st thing tomorrow! ... I'm at 240ML total for the outers now ...

 

[JasonfromMN]

Sounds like your forks are starting to work well for you! If you remove "a couple shims from the compression stack", don't you worry that it'll bottom even much easier?

So I got mine back last week, rode it last Wed. On the smaller chop they work very well, like the small chop isn't even there. On the mid sized stuff they're still a little stiff. When I talk with him this week im going to see if he can work that out with out sacrificing bottoming resistance. If not, i'll leave them alone. For now.

 

[ray_ray]

You probably just need to give some feedback on the action of the forks and he'll hanve U another adjustment to dial them in some more ...

Yes it might bottom more on the track, but I don't think so on the trails ...I'll have to do a different set up for the days riding depending on track or trail if I ever get this far ....

Removing the oil from the outer has helped alot but I think I might have removed too much now as I was hearing a little clanging noise doing some small jumps on the trails ... ... I'm gonna add some oil back till the noise is gone ...

 

[JasonfromMN]

Talked with the tuner today!! Im very pleased and a bit surprised that, ok some suspense here........ here it goes- he added BV, or compression valve shim's to the stack to make it softer****************************************! Why is this so surprising you ask? Because by adding shim's to any stack makes the stack harder to deflect the oil making it flow slower making a stiffer suspension. The reason this makes mine softer is because now im riding much more up in the stroke, where the valving is softer, get it? Yeah kinda like an a Rubik's cube.

So it turns out ive been blowing through the travel to the near bottoming portion of the forks, where its stiffer- making it stiff, Ha! (ring a bell ray_ray?:smirk

(ray_ray, im going to have to go crawl back to TT so they can say "I told you so". Not that I ever told them they were wrong. They might like to know they were right though)

So next step we agreed is to probably go to the next stiffer springs. I am going to try to add some pre load to the stock ones just in case I can get away with a cheap fix. He did say these forks in stock trim are very under valved. I agree. If you take them apart, theirs just not much there.

Once again-

 

[ray_ray]

I get part of this and I finally think I understand the idea of blowing thru ...

If you divide the 12" of fork travel into 3 4" segements, U get the entire 12" stroke, with each of the 3 segements doin work, and each over lapping each other ...In your case you are saying the middle segement is not doing any work so the fork passes the middle portion and hits the last segment that is harder by design ...

Are you saying this BV shim alone helped keep the forks operating on the upper shims before the blow through to the bottom portion of the forks?

Adding the BV helped this ... What is a BV shim?

You state you are riding higher in the stroke but are going to try stiffer springs to raise them ever more? What does UR sag look like now up there? I got very little sag ...

 

[JasonfromMN]

Of the 3-4" segments, my forks were going through the 8" very quickly(un-noticeably apparently) and often riding in the last 4" area where the compression valve shims are small and thicker to resist bottoming, except thats where I must have spent most my time riding. The BV is just the base valve also known as the compression valve. Its just easier to type BV.

So yeah, adding BV shim/shims(?) seems to have me in the first 4-8" area more often. It must be softer because adding shim/shims, keeps me in the area of the larger, thinner, easier to deflect shims= softer action. This really makes valving much more complicated. So now I know that removing shims on a properly designed stack should soften the stroke depending on where and what you remove. Also adding shims to a improperly designed stack like mine puts you in a different part of the stroke altering action. Spring rates change the portion of the stroke we ride in, thus the area of shims we ride in, altering the action. Oil WT changes how easily/hard it can flow through the shims, altering the action. Rebound dampening too soft can make your compression feel altered and visa versa. Wow thats got to be hundreds maybe thousands of possible combinations.

So, Yes I probably need stiffer spring because even though he stiffened the valving, it mostly only affected the smaller hits, meaning Im still going down too far in the stroke. It also means the proper solution is to start with springs to put me in the right part of the stroke then worry about valving if its not what I want because otherwise adding shims would have had the opposite affect.

My sag is now after adding 1/8" washer for preload, about 3/4". Im going to reseach what that means.

Whats your sag? Seems to me if your needing to remove so much oil to make them softer and getting clunking, while still bottoming on the track, you might want to look into stiffer springs. That would put you in the upper softer part of the stroke for trails, and help prevent bottoming on the track at the same time. Remember my TT thread, stiffer spring don't necessarily mean stiffer action? Don't take it from me though....

 

[ray_ray]

OK ... this valving and shimmng is making a little sense ...theory wise anyway ... I've read before where there are numerous ways to get the same effects on the forks that will make the rider happy ... I doubt I'll fully understand this unless I actually move the shims around on my bike ... Changing the oil wt and volume was interesting though ... WT just changed the feel and the volume just removed harshness \ controls bottoming ... shims do the real work ...

My sag is about 25MM or about 1" ... UR at .75" or 19MM ... from what I've read, that is very little sag as most have read say about 35MM is mid point, give or take 10MM ... That change put u well up in the stroke ... You should feel some different from that setting I bet .... But, UR so high now, U might get other side effects ... Maybe n corners or something ... My front end is biting very good now ... this thread talks about sag a little ...
http://www.cafehusky.com/forums/showthread.php?t=8094


I have always read where the spring sets the initial starting point for the stroke, front and rear ... It just holds the bike up on the forks and has little to do after this in the actual action of the forks ...

My forks have the pre-load clip so I just load mine up when I was changng the oil ... I took too much oil out but I wanted that so I could see what the boundaries are ... I can add back in 20CC easily and they will most likely will stop the clanging noise ... Probably 260 - 275MM is where the oil level should be on mine ... As long as get smoothness on the trails... that is good enough ... Tracks are secondary to me ... and at the worst, I add oil back to them (285ML ++) for that to stop the bottoming ..

I'm not gonna buy springs or anything othere than some shims ... and not the expensive stuff ... I got no job and no money for this, unless it is just a few bucks ... I'm really happy with these dual chambers ... No extra $ paid out to get where they are today ... There is another guy on here who has the same bike as mine and he only changed the springs to get his to work on trails and the track via the clickers ... I have never read that this is possible but about twice out here on these sites ... Everyone is pretty much valved for track or trail, but not both ... I'm gonna go back and duplicate some of his setting over time ...

 

[JasonfromMN]

Ok, so I did the sag wrong. I'll have to go out and check that now. I guess I assumed the rider needed to be on the bike like the rear. Just talked to my tuner and he says no, need to check the bike on the wheels, mark a spot, then on a stand to check how much they dropped. Should be about 30-40mm. He also said you should be able to bounce the bike in the mid section and the front and rear should bounce pretty much together maybe a little more on the rear for good balance. Of course thats generic though. I know on mine they bounced together but maybe a little more on the front which points to too little pre load or soft springs.

 

[ray_ray]

Yes, the no-rider weight seems a little weird to me also ... If you keep the distance of the extended forks, U can always check the sag easily because U have the extended number without measuring ... Not sure how it should be affecting my bike but my sag is 25MM .... not alot of sag here

Added 15ML of oil back today ... I'll be testing it shortly on the trails

 

[JasonfromMN]

Im at 25mm also. Seems odd, I really thought they would be too much sag considering my issues. Turns out I know quite a bit about how forks work now, just not $hit about how to make them work.

I got to swap bikes with my old WR250F 07 this weekend. I wanted to see if by riding with a guy faster than me, made me a little faster, maybe making my suspension feel stiff when Im really just going faster. Nope! Its stiff he agreed. He hit a big stump with both bikes, the WR wheelied off it but soaking up the impact real nicely. The TE almost broke his goggles. Anyways I rode the WR and the suspension soaked up the trail junk nicely but still bounced on some of the deep rut crap more than I thought it would. Overall is was not quite as plush as I thought I remembered it to be so a small +1 for my Husky. I was real glad to get back on my Husky. But theres still work to be done. I think one more trip to the tuner will get me just under the wr's chushy-ness and that'll be that. Time to start enjoying the Dang thing. I'm getting tired of being hyper-sensitive paying the utmost attention to every possible movement the forks make.

 

[ray_ray]

Yep.. I think when U get to the point where you are just riding and not worrying about what items U are hitting on the trails, Ur forks are Ok :0) I can actually look for stuff to hit and jump across now ;0)

UR tuner will probably hook U up next time... U'll just have to hang with him ....

One think I don't understand on these shim stacks 4 sure, is when the different aspects of the stack comes into play ... IE ... where does one segment of the forking action (the top part) overlap and change to the mid range of the fork action and next on to the over bottoming resistance of the last 3-4" of the fork travel ...

For example ... We know the big shims closest to the piston are the soft travel at the top but where to these transition over to the MID range fork action? And where & how, does the MID range translate over to the final forking action at the bottom of the forks?

 

[JasonfromMN]

Great question and I agree, difficult to understand. The way I interpret it is this- The few larger shims nearest the piston could in fact be the only shims to deflect all the way down to bottoming. I believe they are not exclusively related to fork travel but to "pressure". If all the hits are soft, you stay in the lager shim/softer area. As the hits get bigger, that means faster fork travel, more oil pressure and you end up in the more mid range shims. Big hits, jumps ext= huge oil pressure. That huge oil pressure just blows through the larger and mid sized shims right to the bottom ones. For example, if you were super strong and could hold your front brake and push on your forks in the garage until they bottom, you'd be only working the first one or two shims even though you just bottomed them. If you jumped on them now the compressing action is fast creating more oil pressure. That oil pressure is what starts to deflect the shims further on down, not fork position. You could theoretically build a shim stack with all the same size and diameter shims. It just would change the behavior of how the forks compress under the pressure.

 

[ray_ray]

OK ... So the entire stack might be involved with each hit with a relation to the amount of pressure applied to the forks ... Big pressure, all shims involved including big ones that deflect on to the smaller ones, ... smaller pressure, only top shims deflecting to a certain point...

This again makes sense .... But I still can't see how the hand off occurs between the shims as the pressure builds and the pressure causes more shims to move to the different individual shims on down the stack...

for example ... In the case of MID size pressure build-up, the upper shims plus some number of shims below it must come into play ... the upper shims deflect and then these same shims press on the next shims below it, correct? This idea continues through out the entire pressure range of the forks?

 

[JasonfromMN]

But I still can't see how the hand off occurs

Your thoughts are correct in your example. I wish I could draw a picture of it. To start from the beginning, as you hit a MID sized bump, the bump presses your lower fork tube in the outer(upper) fork tube. My lower fork tube has the piston in it. So as the lower presses into the outer, the piston is also moving through the tube pushing on the oil. Whats actually pushing on the oil is the piston loaded with all the rebound shims. The shims cannot deflect backwards because they rest on the piston face their for they have to move oil. That oil then gets pressed through the base valve piston but the other way so it moves through the 3-4 holes in the base valve piston then on exiting the piston in order to get out it has to deflect, or "bend" the first face shim. Well if the hit is a MID sized hit the oil is flowing fast with good pressure so it will bend the first shim hard enough for that shim to start bending the 2nd shim. As far as it bending the mid or bottom small shims, as all the larger shims deflect, or bend, they are bending on the smaller shims surface. Its harder for a large shim to bend a smaller shim compared to a larger shim bending another shim of the same size. The larger the size the more leverage. Thats why as the hits get bigger, the pressure gets bigger but you still have resistance to bottoming. Its hard to bend the small diameter, or thicker shims. Man I hope Im not making this more confusing. I think you understand it, just need to think of it from the beginning and maybe look at the parts as you go through the oil flow cycle.

Your last paragraph is correct and makes sense.

Yep.. I think when U get to the point where you are just riding and not worrying about what items U are hitting on the trails, Ur forks are Ok :0) I can actually look for stuff to hit and jump across now ;0)

Yeah, thats how the shock is. I never have to think about it- just ride.

Talked with tuner dude again tonight. After finding out what my sag is we agreed the springs do not need to be changed but to probably still go stiffer on the valving, remove my preload washer I added and maybe even remove a little more preload since I was at 25mm when I should be between 30-40mm. Seems overall maybe the fork springs might be too stiff and the valving too soft. We'll see. Have you ever tried backing off on your preload(since your at 25mm) and adding some compression clicks or something? Gone that direction?

 

[ray_ray]

This is actually a little easier to understand ... after the pressure from a hit gets past the first few larger shims, the the entire shim stack, including the top ones, work together to provide cushioning from the ~MID stroke to the bottom ...

In your case, which seems typical from what my bike was acting like and from the many fork issues I have read here, you are looking for mid pressure smoothness ... So your top shims are OK and maybe the bottom 2-4 smaller shims are OK but the bottom ones are really unknown at this point but should not be causing the issues U have ...

So, you are going to work on the middle shims again to help the action stay higher on the shim stack ... and this can be done with larger diameter shims or thicker shims ... in the middle section of the stack? Or maybe both different types of shims cane be used...?

I can see where your suggestion on my forks could pay dividends ... and I can see here also how my current setup works also .... ... 2 different ways to get the same basic feeling ... When I was playing with the sag, I came through the larger sag ADJ maybe too quickly and did not test enough there really ... What problems does too little sag in the front cause?

 

[JasonfromMN]

Not sure what too little sag in the front will cause but I know that means the springs will start off too stiff right away. Of couse the rest depends on the valving. Your right to say the entire valve stack works together, but not necessarly the mid shims for the mid stroke, but maybe. Really just depends on the entire arrangement configuration. Your also right im looking for MID PRESSURE SMOOTHNESS. Not necessarly mid stroke smoothness, since its all relative to pressure and shim arrangement.

My situation seems odd because im adding more valveing and less spring preload for my next try. My tuner sent me shims and told me where he wants me to place them and how much preload to remove from the springs. After this next step, my forks will have added about 5-6 shims each leg in the compression stack. Thats a lot! We'll see how it works but right now one of my legs has been weeping oil either from too many times taken apart or possibly from them getting shipped in a horizontal position and a bunch of oil getting in the wrong area's and slowly leaking out. Its a puddle on the floor though

 

[ray_ray]

Too bad on that weeping ... U have to pull the tubes apart each time get at the valves?

Sounds like you are getting some real tuning experience now

Mine are still acting well on the trail... Rode 2 days on the trails last week in all kinds of stuff and no issues really ... Did a few track laps and I gotta get my oil level back up for sure there ...

Back up to 2 265ML fluid in the forks after adding another 10ML last night ... I'll be testing this later today ... Preliminary results are that I took out way too much oil to get a plush feel