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Discussion Starter · #1 ·
Hey guys! I have been having problems with my front suspension for a long time.i turn to you since I ran out of options.
We all know how stock front suspension acts and I won't go over it.
I have sport1000 biposto. I fitted 900ss front forks and now it feels like it locks up on me when I'm riding. It feels stiff like they don't even move up and down but only over wavy surface.
They act just fine over any significant bump that you can actually see. Bike feels like its springing up and down on the freeway, almost like its not heavy enough to compress suspension.
I had tried more than one set from st4s, s2r, and now 900ss. They all do the same thing. So I know it's not internal issue. If I try stock set up, it doesn't do what I have described, but all the other crap comes back.
This springing feeling wears me out-sucks to ride it this way.
If I open damping udjusters all the way, it's much better, but it's too soft that way.
I have st4s wheels on, other than that and exhaust, it's stock.
I'm almost ready to put old forks back on.
There is probably 30mm travel left even with preload at the lowest and under heavy braking.
 

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A springing feeling is due to lack of rebound damping because the suspension is recovering too quickly. The stiff feeling may be too much preload or eff'd up compression damping which isn't letting the forks move freely. Lastly, if your triples are too tight, the suspension tubes may be binding. Take your bike to an experienced suspension guy and get it set up properly.
 

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Dave Moss, Catalyst Reaction. He's one of the best for suspension work.

Catalyst Reaction LLC
15401 red hill ave #F
Tustin ca 92780

P: 714-258-7501

Should be an hour or so from where you are. Well worth the time to bring your bike to him.
 

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or a little closer to you: West Coast GP Cycles on Pico and Bundy. Gurus.
 

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If three sets of forks are doing the same thing, but not on their respective stock bikes, your front wheel might be too narrow at the axle and pinching the forks together - or pushing them apart - which would cause binding and the "hopping" over the small bumps like you described.
 

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What Chuck said, they should work fine IF installed correctly , spacers in right places, torqued to spec, something is not right going back together. Should be direct swap say for S2r forks, axle size the same but there are spacers on front wheel hub.
 

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Discussion Starter · #9 ·
If three sets of forks are doing the same thing, but not on their respective stock bikes, your front wheel might be too narrow at the axle and pinching the forks together - or pushing them apart - which would cause binding and the "hopping" over the small bumps like you described.
That's what I'm starting to believe. Hopping is probably best way to describe it. And it feels like its binding over small bumps. We are talking about bumps you can't even see.
Stock forks bottoms and all the other once I tried are the same. It should not make any difference.
St wheels are narrower, but I used superbike axle with correct spacers. But something is telling me it's the wheel/axle issue.
If I seat on the bike suspension compresses. If I stand up and seat back down about 3-4 times front end fails to return to original height- unless I pull on the handle bars. It's defiantly binding. I tried correct sequence to tighten triple clamp/ axle without success.
Can it be brakes? They drag a little. I'll try to retorgue front end again one more time! If no success, I'll be going to the shop you guys recommend.
I have sold other forks I tried on eBay with promise to take them back if anything wrong. Never got any complains. It must be me:)
I have tried local shops before, but they didn't find anything wrong. I think I need a real pro! But I'll look at the axle again.
Any other ideas will be appreciated.
Thanks!
 

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If these guys are right about the binding issue, than it will be fully apparent from a stiction measurement. I'll assume you have already measured sag and know how to do that. Try compressing the suspension and then letting it rise very slowly until it sticks (stops moving). Measure from your reference point. Then lift the suspension and let it fall very slowly until it sticks. Measure from your reference point again. The difference between the two measurements is the stiction. If it is less that 15 mm you don't likely have significant binding.

The feeling you describe of the suspension feeling rigid over gentle waves in the pavement is not an uncommon sensation when you increase the spring rate. Do you know what rate springs you have, and how they compare to the stock ones?

Also, what are your rider sag numbers? How about bike-only sag?
 

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One thing you can try for a binding issue,
Loosen the two axle pinch bolts on the right fork lower and then push on the front end and see if it frees up, if it does then sung them up and check again. The right side is the "floating side"

Frank
 

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"Take your bike to an experienced suspension guy and get it set up properly."

+1
 

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Discussion Starter · #14 ·
Thanks to all of you guys!
I didn't have time to play with it today, but tomorrow I'll get numbers.
I have tried tricks with floating side of an axle,etc, all looks normal. It is binding though! I'll measure exact number tomorrow.
Sag is like 50mm. The only way I can get it close to 30sh is with udjusters all the way in.
I have tried in the past race tech springs with correct weight, but it didn't do a damn thing. Same issue!
Those springs worked fine with stock forks though!
All this doesn't make any sense! If current springs are too weak with 54mm sag,how come I only use 2/3 of travel under any condition??? No where near bottoming it!
If they are too stiff how come it sags so much?:):):)
I'm sorry, I'm driving you crazy! But!
I know for a fact, any place I take her too will want to take everything uppart, charge me bunch of money, give it back to me saying its fine.
I was hoping to figure it out myself-at list try first.
Does anyone have 900ss forks on? Can you tell me exact number you have showing above triple?
I have my clip ons mounted above triple, that's why I went with this set up.
I'll mess with an axle a little more before I take it to the shop. Just to make sure.
 

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If you have a 54mm sag, and the legs are binding, then something is definitely not right. Springs for your correct riding weight matter, whether they are linear or progressive also matters. Fork oil levels also matter. As does proper seating/alignment in the triples/axle. Forks are not easy to set up. You either must have patience, time and access to all the available information to do it right, or you take it to a suspension shop that can do it right for you. The latter will relieve you of the frustration you're feeling, and will cost less in the long run.

The choice is your's, but hearing that you've gone through 3 different forks with the same result says to me that you would benefit from having a Pro do it for you. If you're lucky, you might be able to watch them do it so you will know how to tweak them to your liking going forward.

Good luck and don't give up!

Tmnstr


Sent from my Motorcycle iPhone app
 

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I'd sure like to see the stiction number, but am now also curious about your oil height! If you have 54 mm sag and still can't get it into the last third of travel even under heavy braking....kinda makes me wonder...maybe there is too much oil in them?

When you set the oil height, did you do it with the springs out and the fork completely collapsed?
 

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Discussion Starter · #17 ·
I'd sure like to see the stiction number, but am now also curious about your oil height! If you have 54 mm sag and still can't get it into the last third of travel even under heavy braking....kinda makes me wonder...maybe there is too much oil in them?

When you set the oil height, did you do it with the springs out and the fork completely collapsed?
Thanks for all your help guys! I think I'm going to give up on this project for now, untill I see specialist.
I have never opened this particular set, so oil height must be standard for 900ss.
I have tried lower oil level in the past without success. Honestly! I have tried everything! I was kinda looking for a person who like me have tried everything and found something unusual causing this such as may be something to do with rear suspension or god knows what. I'll just take her to the shop. All the things you guys have mentioned are potential reason,but I have checked already.
Oil height, viscosity, sticky dust seals, clean new oil, springs and spacers, even race tech guts and gold valves! Everything!!!! I officially give up!!!!
Going to the shop! I can now do this forks with my eyes closed, single handed, created all kinds of compressors for springs to do it without help, but one thing I failed is to find a problem!!!!
It's ok -suspension shop it is:):):)!
I'll throw eom for now and be happy!
 

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Discussion Starter · #18 ·
I placed original forks back on, and everything is fine. That means there is nothing wrong with my front end!
If nothing wrong with the bike that means it just doesn't want to accept this forks. I know it worked for many people here, but there are so many variables, including wheels and weight of the riders, almost impossible to compare.
I'll try again with suspension shop involved.
Thanks to all of you!
 

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Discussion Starter · #19 ·
I'd sure like to see the stiction number, but am now also curious about your oil height! If you have 54 mm sag and still can't get it into the last third of travel even under heavy braking....kinda makes me wonder...maybe there is too much oil in them?

When you set the oil height, did you do it with the springs out and the fork completely collapsed?
Hey guys I'm back.
I was wrong! Again!:)
Hopping was still there,just less noticeable with stock forks.
I think mr Duck is right!
I'm filling forks to factory specs, but I think it's a bit to high for me.
So I took stock set apparat, and they were at 90mm oil height.
So! I took 50cc out of each leg and got much much better. With 90mm I was using only slightly more than half of travel. Now it's about 2/3. I took about 20cc more but have not tried yet. Sag is about 33mm on stock forks.
But one thing is for sure, travel is increasing little by little.
I think I'm riding on air pocket rather than springs. Thats wy it feels like they are binding. Signifficant bumps would compress suspension, but little waivy surface would not.
Once I set this forks up I'll go back to 900ss forks.
 

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Discussion Starter · #20 ·
I moved PVC spacer to the top. Drilled it through so I can use that spring compressor. I'm holding rod with rubber hose attached to anything above with rubber bands. Works good when you are doing it by yourself.
May be someone else have done it already! I don't know!
 
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