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Discussion Starter #1
I love my S4RS but it’s beating me to death on my local roads. I could find no adjustment settings on the forks that alleviated this. The forks started leaking so I replaced the seals last winter, verified that the spring rate was correct for me, and replaced the fluid with the documented volume from the top of the tube. I did not bother measuring the amount that came out as it wouldn’t have been correct anyway due to leaking profusely on both sides for a while. Also , the forks were so harsh I wasn’t sure they weren’t overfilled to begin with. I used 5w synthetic fork oil, Spectro , IIRC. Nothing was found wrong internally, and the forks were thoroughly cleaned.
What I’d like to know is , if you’re happy with the forks, what fluid you are using ? What was the fluid height you set ? What compression and rebound adjustment are you happy with ? Please do not give me the “ everybody’s different “ speech. I’ve heard it all. If you’re not going to give me some baseline settings, please don’t respond at all. The suspension on this bike is downright punishing. Before I send them to someone for professional work I’d like to exhaust all options.
 

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I love my S4RS but it’s beating me to death on my local roads. I could find no adjustment settings on the forks that alleviated this. The forks started leaking so I replaced the seals last winter, verified that the spring rate was correct for me, and replaced the fluid with the documented volume from the top of the tube. I did not bother measuring the amount that came out as it wouldn’t have been correct anyway due to leaking profusely on both sides for a while. Also , the forks were so harsh I wasn’t sure they weren’t overfilled to begin with. I used 5w synthetic fork oil, Spectro , IIRC. Nothing was found wrong internally, and the forks were thoroughly cleaned.

What I’d like to know is , if you’re happy with the forks, what fluid you are using ? What was the fluid height you set ? What compression and rebound adjustment are you happy with ? Please do not give me the “ everybody’s different “ speech. I’ve heard it all. If you’re not going to give me some baseline settings, please don’t respond at all. The suspension on this bike is downright punishing. Before I send them to someone for professional work I’d like to exhaust all options.
I'm thinking your fork oil is too heavy...ohlins, despite the number 5 on the bottle is near water...other than that I'm 175lbs running a 9.5 spring with an 80cm air gap with 4 turns in from all the way out on rebound and 20 turns out on compression...your tire is ultimately going to tell you what you need...but I hear your complaint..I went up a spring rate and left my settings as before and it hurt to move my arms after a long ride...I'd recommend a lighter oil and open up your compression and rebound a bit ...perhaps remove some fluid too just be careful your not slamming into the bottom of the stroke under extreme situations

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There’s actually two damping circuits to consider— low speed damping that’s controlled by how many clicks you set — and high speed damping that’s controlled by the internal shim stack.

Compression damping is what makes a bike ride “hard” on bad (normal) roads. You want to dial in as little as possible without making the bike handle poorly. This takes a bit of experimentation. Not enough compression in front causes fork dive. You can bottom the forks on hard braking. Too much causes the bike to loose control on bumpy turns and feel too busy.

Too much compression in the rear will wreck your spine and cause the back to bounce all over bumpy corners. Too little will make it feel sloppy. A little compression damping here goes a long way.

When you hit most bumps, the low speed damping controls how quickly you stop bouncing. Too quickly and the bump feels jarring, too slow and you find the bike bouncing for several cycles after which gives you the feeling that there’s not enough control of the bike movement. So you set damping to strike a personal balance between jarring and bouncy. Adjust your damper for full soft, and again for full hard. Ride around to understand the effect of the range of adjustment available.

When you hit a quick bump like a pothole, the hydraulic fluid just can’t flow fast enough through the small adjustable orifice that you use to set low speed damping discussed above. So there’s an internal shim stack that lifts like a pressure relief valve to allow more fluid flow and consequently less damping during the event. After the high speed suspension movement event, the shim stack returns to its normal closed position.

There are shim stack replacement kits like the Race Tech Gold Valve that allows you to have some additional velocity sensitive damping adjustment. The idea here is that the gold valves (I’m quoting) “lets the damping rate be optimized for small, low velocity, fork motions where oil is forced between the valve disk and body, but lets the spring open up the valve to provide more oil flow when large/fast fork movements occur. By adjusting the tension in the spring you can tailor when and how far the valve opens, that is, when the transition between damping that's good for small bumps and damping best for big hits occurs.”

So, as you ride, make a distinction between slow and fast bumps as they affect ride quality — then you’ll know what to do.

I'd start by decreasing low speed compression damping to its lowest click setting and take a test ride to understand your adjustment range using your current fork oil viscosity and to see if your problem is low speed or high speed damping. If the problem is low speed damping related, gradually raise the damping to suit your personal comfort level.
 

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i have a customer who probably weighs 90 - 95kg at a guess. he is running i think a 0.90 and 0.95 spring, or maybe 0.85/0.9, forget now. i think his have been played with - knowing him, i'm sure they would have been.

ohlins 1309 oil (19 cst at 40 degrees) set to 85mm with white guide in, but not spring. i think it was 95mm, and he wanted to try a little higher. spec is 170mm. settings c: 12, r: 10, p: 2.5 turns.

sounds like something is wrong to me if they're too harsh. is the valving original?
 

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Discussion Starter #5
I don’t know whether the forks have been played with or not. I tried to contact the PO but wasn’t successful. I’ve now dialed compression all the way out but haven’t tried it yet. It’s not just comfort, the front tire is not maintaining road contact very well either. Bumps in the middle of curves could be challenging. I thought the 5w fluid would be comparable or maybe even make things a little more compliant, but it didn’t. Everything internally looked fine.
 

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In stock form those forks are usually under sprung for most riders, when they first came out we though the front brakes were strong but it was mostly due to dive.

I may have missed it but where are they too harsh?
everywhere?
bottom of stroke?
mid stroke?
As mentioned be sure to differentiate between high speed damping and low speed, remember we are talking shaft speed.

Is the bike chassis otherwise stock?
Does it have clip ons.ape hangers or oem bars?
Has the rear ride height been raised or lowered?

Were you ever happy or did the problem come with the oil change?
Is the bike using all its travel under maximum conditions?
Have you measured travel?

I have had a oem ohlins bike come in where the rebound adjuster had been jammed closed internally due to improper assembly I also bought a set of used ohlins that had been screwed up internally by a prior owner including welding of the cartridge body and a large house fly being in the valve stack... I kid you not!
 

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I don’t know whether the forks have been played with or not. I tried to contact the PO but wasn’t successful. I’ve now dialed compression all the way out but haven’t tried it yet. It’s not just comfort, the front tire is not maintaining road contact very well either. Bumps in the middle of curves could be challenging. I thought the 5w fluid would be comparable or maybe even make things a little more compliant, but it didn’t. Everything internally looked fine.
Think of compression like a volume knob for feedback...too much and you feel everything...too little and your on a cloud...but if your rebound is out to far the bike will pogo in the corner...if it's too tight it will skip off the bumps....also if the rebound doesn't match the rear it will feel very unstable mid-corner as if the bike is rocking back and forth....a simple way to adjust the rebound is to look at the tire tread....if the forward edge is wearing down it's too fast and needs more damping, clicks to the right....if the trailing edge is worn it's too slow, clicks to the left....same for the rear but only look at the tread were your on the throttle...everyone's shock is too fast when coasting and will give you the wrong read...

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the way i see it you have 3 options.

1/ keep complaining about it.
2/ pull it apart again without any real idea of what you're looking for.
3/ send them to someone who knows.

only #3 is going to help you.
 

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Discussion Starter #9
I like to fix things myself if possible. I won’t learn much if I send them out. When I assembled them last winter I had the wrong oil height but someone here corrected me and I lowered it. It is summer here belter so I’m not going to disable the bike until cold weather. I’ll send the forks out then if I’ve had no success. I don’t have a ton of experience on adjustable forks but I’ve rebuilt them several times before with no problems. I haven’t had any issues with the others. I did the GSXR conversion on my SS with no problem and good results.
In Michigan we have a wide temperature change that causes the roads to compress and form peaks at the cracks, some roads every 10-20 ft. Those little peaks are what the forks don’t handle. I have those roads near my house. The Ohlins forks don’t seem to want to handle those small risers, sending the jolt straight to me. This is not the case with the Showas on my SS or Busa. The springs are .90 in both Ducatis. I weigh 195# in full gear and both bikes weigh about the same.
I have a zip tie to indicate fork travel and will go for a ride today. I’m thinking I may change to lighter fluid to reduce damping as my next step.
 

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are the shims stacks original/correct/appropriate? that's really all that's going to effect harshness. oil height won't, unless they're full to the top.
Lol...I read that wrong...I though it said oil weight wouldn't effect harshness.....but he's right...if your say way low on oil height you will be using the spring tension alone for your damping...which is fine, provided your not pushing hard enough to hit bottom.... conversely if it's too high, your robbing yourself of fork travel and is the same as hitting bottom but on a shorter stroke... nonetheless...

...open all your rebound...and compression....open it to zero...all the way out...if your ride quality doesn't feel any better than something needs to be done internally...be it lighter oil, valve job, or a more invasive cleaning...if the ride quality has improved for the better than start advancing the rebound and compression 5 clicks at a time back in...take your time and don't expect perfection on the first go...I know Michigan...grew up there...potholes are impossible to tune a suspension to...cracks are abrupt suspension inputs and equally challenging plus wildly dependant on your speed...I've got a road that local riders avoid mostly and it's my benchmark...but when I hit a road that's properly riddled with patches I'm all over the place looking for traction....one setting won't fit all...but a common setting will make them tolerable...this is speaking in terms of comfort above "pace"...if you don't feel more comfortable with everything open....was it because it moved too much or not enough....without movement there is no damping

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Discussion Starter #12
Ok, rode about 60 miles yesterday, all paved back roads. No preload, rebound 12 clicks ccw, compression totally ccw. It was better. It was tolerable. I checked the rear shock settings. That was : rebound 12 clicks ccw, compression 20 clicks ccw, which I changed to 12 ccw. There is not much preload on the spring ( I removed most of the preload last year) . I’m going to start dialing more compression out of the rear on each ride. Rebound front and rear is on the stock recommendation, 12 clicks ccw. I’ll dial that out about 4 clicks at a time and see what happens. The bike is still handling fine, with noticeable nose dive during a panic stop, as would be expected. It wasn’t anything I would deem excessive. The small “ risers” were better, the risers they patched with a foot wide “ speed bump” were still not taken well, and rough pavement was still horrible, but just a little less horrible. Dirt roads , I live on one, were better.
I don’t know what to expect dialing back rebound, but I’ll try it. I’ll dial the rear compression down and see what that gets me, though I don’t feel like that’s too bad now. Thanks for all the input, everyone.
 

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Now that progress seems possible let's keep safety on the agenda...without any preload your at a significant risk of bottoming out...maybe not cruising but definitely in a panic moment...you should place a zip tie around the fork leg and keep an eye on it...if it ever smacks bottom add 2 turns of preload...preload keeps the fork working at the proper height of it's stroke...that said when your wrenching down on the preload your mostly just collapsing the top out spring anyway...if you feel 5 turns is too much than you will want a lower spring rate....rebound is critical in terms of grip and tire wear...just keep an eye on your tire wear...tires can't lie




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I’ve been down this road and without the proper Ohlins fork oil (whose weights bear no relation to the rest of the fork oil world) you’re chasing your tail.
 

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Discussion Starter #16
Yeah,I think that’s what happened. I used 5w Maxima or Spectro and thought it would be light enough, but apparently I was mistaken. I now have dialed compression damping fully ccw front and rear. One serious panic stop and assorted front brake applications and my zip tie is about an inch from the bottom. My sag is on the low side, as in barely to the minimum. I’ll add a few clicks cw before I ride it again. I have some mammoth holes hidden in the shadows on the dirt roads around me. If I manage to get sucked into the gravitational field as I approach one I might need a little more preload.
Buhgaboo, your theory on spring compression only applies to springs that aren’t straight wound. A single rate spring should theoretically deflect a little over the entire length. This is why bikes with “ progressive rate “ springs nosedive more, there is more deflection occurring in the tighter wound , lower rate section of the spring. If you have progressive rate springs, your preload adjuster will also work progressively because initially the adjuster will mostly compress the lower rate end coils.
 

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Yeah,I think that’s what happened. I used 5w Maxima or Spectro and thought it would be light enough, but apparently I was mistaken. I now have dialed compression damping fully ccw front and rear. One serious panic stop and assorted front brake applications and my zip tie is about an inch from the bottom. My sag is on the low side, as in barely to the minimum. I’ll add a few clicks cw before I ride it again. I have some mammoth holes hidden in the shadows on the dirt roads around me. If I manage to get sucked into the gravitational field as I approach one I might need a little more preload.

Buhgaboo, your theory on spring compression only applies to springs that aren’t straight wound. A single rate spring should theoretically deflect a little over the entire length. This is why bikes with “ progressive rate “ springs nosedive more, there is more deflection occurring in the tighter wound , lower rate section of the spring. If you have progressive rate springs, your preload adjuster will also work progressively because initially the adjuster will mostly compress the lower rate end coils.
we're sweeping through broad strokes here...im looking to separate oil viscosity from spring rate....wrenching down on a progressive spring, which you don't have, or you would be complaining about hitting bottom and not a harsh ride, would still give the same results...1in from the bottom with no preload and no compression is about 25mm...making the only thing keeping it from hitting the bottom theoretically is the air gap...and that's what you want, just not with 0 turns...Provided you gave it the gusto on brakes...try it again with 5 turns and then 10, you might have a good feel for the bottom and naturally let off the brakes when it's there...throw in some preload and let er rip

Now let's stick with the positives...you apparently have a safety margin of fork travel...but 0 turns of preload only points to a too stiff spring....how did that effect the max travel when you added more preload? How did that effect the sag number? these are oil independent variables

Your compression and rebound settings will slow down the stroke which will ultimately be detected in tire wear given enough mileage (this is so much easier on new tires) which we haven't even discussed....are you using soft carcass pirellis? Hard carcass Dunlop? A hard tire likes a hard setting..soft carcarcass likes a softer...setting...The faster you go... the narrower of margins you have from right and wrong settings...and the longer you ride with a wrong setting the more precise you become with what you want, but developing the language takes time and miles....tire wear becomes your best translator...if you haven't yet... snap a picture of them

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Discussion Starter #19
I haven’t ridden the bike with more preload yet. I’m familiar with how a bike feels bottoming out, and I was surprised I used up that much travel while braking. The bumps that are causing issues are the small stuff. It’s a lack of compliance in the first 1-2 inches of travel that I need to improve. This is the way the bike was when I bought it in Florida, but the roads are way smoother there than Michigan and it was a non issue. I doubt I’ll have time to do any major fork work until the riding season is over. I plan to change to the appropriate Ohlins in a lighter grade than what I’m using now, and I may decide to change springs to the next lower rate available. Is there any way, like the zip tie on the forks, to measure rear shock travel being used ? That would be a help at this point. I really appreciate the input I’m receiving from everyone.
 

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I haven’t ridden the bike with more preload yet. I’m familiar with how a bike feels bottoming out, and I was surprised I used up that much travel while braking. The bumps that are causing issues are the small stuff. It’s a lack of compliance in the first 1-2 inches of travel that I need to improve. This is the way the bike was when I bought it in Florida, but the roads are way smoother there than Michigan and it was a non issue. I doubt I’ll have time to do any major fork work until the riding season is over. I plan to change to the appropriate Ohlins in a lighter grade than what I’m using now, and I may decide to change springs to the next lower rate available. Is there any way, like the zip tie on the forks, to measure rear shock travel being used ? That would be a help at this point. I really appreciate the input I’m receiving from everyone.
You can use a zip tie in the rear as well...typically a dirt line forms naturally so it's not used as often

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