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Report on DDC valves + Nitron shock


faffi

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This is the initial notes because I am not done with the fork yet, see separate question about oil level.
 
Inserting the DDC valves in the forks was easy. I used 5W fork oil with twice the viscosity rating (199 to 102) of the Golden Spectro variant, so hopefully it will perform OK. The shock from Nitron was also a straight swap with the exception of mounting the remote reservoir to the bracket that came with the shock.
 
I didn't check sag before the first ride, unfortunately. Nor did I check sag with the stock items. But I feel confident I have more sag in the rear now and definitely a lot less up front than before - although I didn't know this when riding the bike. Bouncing in the seat in the garage the front felt smooth and controlled, the rear much softer.
 
Out on the road, my first thought was that I had just paid $1400 (with freight and taxes) for nothing. The ride was as harsh as with the stock items. Then I did some swerving, and that was a revelation. With the stock items, swerving rapidly and hard repeatedly would upset the bike no ends, having it pumping madly on its under-damped suspension to the point of almost losing control unless the forces were reduced. Not anymore - the bike stayed "flat" and totally under control at all times.
 
Another benefit was heavily reduced for diving under braking - both in amount and speed of compression. 
 
If it wasn't for that harsh ride...
 
Well, we had a long day ahead of us and there was more to discover. Although still unknown to me at this stage, the higher sitting front and likely slightly lower sitting rear really made the bike much more predictable. Perhaps it required more time to change directions - if it did, I didn't notice. What I did notice was a total confidence under all conditions, and the nervous feel around really low-speed tight hairpins was gone. When accelerating out of the corners, the bike was holding its line perfectly, no need to fight anything. The bike was beautifully neutral in every way.
 
Also, despite having upped the tyre pressure back to stock levels, I had lost the "riding on iron wheels" feel that made me drop the air pressure when riding the bike in stock form. For track riding, I guess the bike would be brill. And it could cope with bigger dips and bumps than before without getting out of shape, and there was no more of the rear kicking back rapidly when hitting something gnarly. But it wasn't actually gliding over the stuff, either.
 
Now about comfort, and why this is just my initial report. After the ride I finally measured static sag. The rear has 41 mm of sag with me on board, and 9 mm with just the bike. This suggest a fairly soft spring with perfect sag, just what I had asked. Perhaps there is a bit too much compression damping - I will not change anything until the front is sorted because I know from experience that a badly set up front end can make a good rear end feel rather lousy. 
 
The front has 11 mm of sag with the bike, but only 27 mm when I'm seated. Not enough. I have upped the preload with the height of the DC valves (about 13 mm, I believe) but also raised the oil level 20 mm over stock. I am confident that is too much and I am trying to learn just how much it should be reduced.
 
To be continued...

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Please follow up on this when you got it sorted out, I will be interested as I will soon start messing with the suspension as well.
My problem is the opposite, soft and mushy suspension like riding a hammock. Lots of fork dive that will rock back and forth twice after a harder break. Undefined feeling in the corners etc.
If you upped the preload, the oil level and probably the viscosity as well the hydraulics in the forks is probably messed as you already figured out, will be interesting to learn how you solve this.

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I measured front end static sag time and time again, because the numbers doesn't make much sense. Yamaha claim 137 mm of travel for the fork, but that must be with forks extended by force - I get 117 mm by how Dave Moss measure. That is, by lifting the front of the bike, but not clear the wheel off the ground. With the wheel in the air I get 122 mm if total travel.
 
Regardless, Dave Moss say to use the stock claimed travel when going for sag numbers, but measure sag without lifting the front wheel off the ground, just extending the fork. 35% of sag from 117 mm = 41 mm. 35% from 137 mm = 48 mm of sag, measure with rider on the bike in gear, seated normally.
 
I got about 40 mm average after shortening the preload spacers by 23 mm, whithout my gear. That is 11 mm off a stock fork preload - the DDC valves are 12 mm tall. Oil level is set to 150 mm with the forks compressed, DDC valves in place.
 
Afterwards, I did the famous Dave Moss bouncing impression. The fork would rebound past its rest state and fall back to its static position, which I am led to believe is about as perfect as a bounce test can get. If I bounced like I believe most people do, and I used to do, the fork simply came back and stopped. But extending it first, then compressing it with a hard, rapid movement seemed to do the trick.
 
I then proceeded to bounce the front and rear at the same time, and they both felt similar in both compression and rebound, perhaps the fork feeling slightly stiffer to compress.
 
Before the ride I fitted a zip tie around one of the stanchions so that I could observe the travel used. Turned out I didn't need them as I could feel the fork bottoming under hard braking. Not harshly, but definitely bottoming out. I will need to raise the oil level to compensate. The obvious answer is that the fork springs are a bit too soft for me, but so is the rear shock - I want comfort and am willing to live with the compromises. Dive is much better controlled than with the stock valving,
 
Apart from the bottoming, the ride was a huge improvement from last time. To my non-expert sensations, the fork with 5W fork oil, DDC valves and oil level at 150 mm seems to work in splendid harmony with my Nitron NTR R2 shock, a 675 lb spring with no additional preload, compression at 12 and rebound at 8 clicks. Over dips, bumps, cracks and speed bumps, both ends worked in unison. Sometimes the fork seemed a little harsher, sometimes the rear, but the differences were minor. I guess some fine-tuning could make them pretty damn equal, but not sure how much more I will mess with things as they are now other than upping the fork oil level until it doesn't bottom anymore.
 
The only issue remaining is with the fork over multiple small, round bumps. These are clearly felt, yet fail to break damping/stiction, leaving the fork rigid. Once the bumps get larger and/or sharper, the fork works fine.
 
The ride isn't Cadillac smooth, but there is plenty in reserve to deal with pretty gnarly stuff. It is felt, but it's not going to kick you in the air or knock the breath out of you in any way. Suspension is firm, but compliant and controlled. Not unlike a sporty family sedan like a BMW M5, although not quite as refined or with as much range.
 
Despite the front sitting lower again, lower than ever before, low speed handling was again neutral and accurate, a clear indication that suspension performance will impact how a motorcycle handles, also at low speeds.
 
I'd say that at this moment, the suspension upgrade was well worth it. More comfort would likely have meant less control. I thought my old 1977 Kawa 650 handled remarkably well while also being compliant, but today I threw the MT-07 through some bumpy esses at a speed that would have thrown the old bike into a heavy shake at best and off the road at worst - the Yamaha didn't bat an eyelid.
 
 
 

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I'm reading up on suspension lately as I'm getting ready for some upgrades. Good post!

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so just how heavy are you? 9/41 on the shock says to me you need rather more spring and less preload. 15/35-40 would be better IMO.
 
> fork with 5W fork oil, DDC valves
 
Whose oil? the 'W' notation unfortunately means nothing. If I had to guess given the photos on Cogent's site the Golden Spectro DDC said to use was 85/150 (aka Race Tech RSF05) with a cSt@40 of ~16 but you went with something north of 22? I don't think the DDC has enough valve area in compression but leaving that aside, you need to go back to a 16 or thinner oil or definitely look at the shim stack to make it more responsive (softer) on the smaller displacement events - maybe a 2 stage stack.
 
Did the DDC also require you to drill the damper rods? Unfortunately the DDC can't really address the IMO primary weakness of the FZ07 forks which is the rebound circuit.
 

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Yes, ideally I should have had a stiffer spring in the rear as well as in the front, but since I want comfort I compromise with more preload that theoretically ideal. The rear doesn't seem to bottom over anything.
 
The Cogent instructions recommended Spectro Golden 5W fork oil, which as a cSt of 21.6. I use an oil rated at 22. The valves seems to control both compression and rebound damping. I may try a slightly thinner oil next time for even more comfort.

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Admittedly I'm going off the pics of the oil bottle in the photo.
http://www.motocd.com/product/ddc-complete-package/
 
Non-cartridge: http://spectro-oils.com/wp-content/techsheets/fork-fluids-5-10-15-20.pdf
Cartridge: http://spectro-oils.com/wp-content/techsheets/Golden%20Cartridge%20Fork.pdf
 
The underside of the DDC is just a spring-loaded check valve - no damping influence. Rebound is a function of how well the seal in the bottom of the fork works and the small hole near the top of the damper rod. Since the FZ07 damper rod is such a piece of crap, you actually need an oil around ~35cSt@40 to rein it it whereas an R3 damper rod is of much higher quality and ~22 will probably suffice. But either way the DDC action would be poor.
 
More often than not soft springs are actually not more comfortable - stiffer springs are. Why? For any given impact the softer setup will travel faster and farther which taxes the damping circuit that much more and often to the point that it can't keep up and the resulting system goes "rigid".
 
Correct oil viscosity arguments aside, I suspect the DDC needs some combination of bleed and lighter shims to do a better job on smaller impacts.

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  • 1 month later...

Yesterday, I finally decided to start messing with the rear shock - all my focus has been on the front end of the bike, finding the correct oil weight and level, sorting out preload. Since stripping the front end is rather tedious, I am not finished, but I am pretty close to knowing what I need.
 
So about the rear shock. It's been rather harsh, but so has the front, meaning they worked roughly in unison, only not well for my requirements. By reducing both compression and rebound damping 4 clicks from what it came with, the ride was completely different. Now the rear en actually smooths out those little niggly things. Over really big stuff, bumps and dips maybe half a foot deep and spread over a yard or three, front and rear seems to work similarly, but the front still needs thinner oil in order to respond better to sharp but tiny bumps. I will have to drain the fork again completely and use Silikolene 2.5W 13.6 cst oil, which I think will be right for our primarily chilly climate. Oil level will be set to 130 mm to prevent bottoming under heavy braking. Then I can start fine-tuning the rear shock further - as it is now, the signals from the front is confusing what I feel from the rear suspension - it's amazing how much one end impact the other.

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I Have been running the DDC valves emulators what ever you want to call them, for about 3 weeks maybe, I have my own comments on another thread.
https://fz07.org/thread/8380/cogent-drop-emulators-metzeler-tires
 
The oil that is recommended has a Cst weight of 14 according to a reliable chart (referenced in my post), I found and mixed 2 viscosities of oil to get a Viscosity of 14.75. very close, the results were actually superb, in both compression and rebound, I suggest you drain your oil and put the recommended viscosity in then adjust your preload, and for a few bucks its worth getting adjuster caps for your forks, 30 bucks on Ebay, it will save endless hack sawing and filing.
My ride is silky smooth and transformed the handling, eliminating nearly all the negatives it possessed before. Whether or how rebound is addressed, (you do not drill the damper tubes with DDC installation BTW), i can't say, but if you use the RECOMMENDED oil viscosity you results will be better. And don't go too much by fork travel, I'm getting only 75 80 mm total travel.

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Thank you for your comments, much appreciated. I prefer the Silikolene oil for its very high VI (464) and will try a straight 13.6 first - I can always suck some out and mix in a little 5W to get to your recommended 14.75 later if it feels too soft.
 
I have adjustable retainers, just waiting for the missing top plates to arrive so I can fit them. With static sag of around 40 mm and the fork oil set to 130 mm with the DDC valves in place, my fork will bottom out under hard braking on smooth ground. So I will need to add more preload. Or fit stiffer springs.
 
I feel the bike could actually use a bit more rebound even now (fork oil mixed to approx Cst 18) when I change directions rapidly over roads with big undulations that in extreme cases can become like that the picture below, but that's not the norm. And the simple solution is simply to slow down :D
 
Telehiv_169_1.jpg
 

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There's another thread on somebody using the Ohlins Fork Spring+Oil kit he sourced from Italy and that oil was rather more than 100cSt@40 and no "ill effects". If I were in an experimenting mood I'd run one leg with the DDC and say a 19cSt oil and run the other leg as OE (but probably with an extra 10mm hole in the rod) with varying grades of heavy (40, 70, 100) to find rebound performance.
 
Harshness in suspension is most of the time the case of too much rebound damping. You want suspension to return to base as fast as possible without setting off oscillations. On a new (to you) shock I suggest setting comp wide open and taking your sweet time getting rebound where it needs to be. The comp valving is what you'll feel on any kind of impact situation, anyway.

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Thank you for chiming in, pattonme :)
 
I guess there are many ways to get a good result - especially since good vary so much from one individual to the next. Some like a firm ride, others a soft ride. I am in the latter group.
 
On my KZ650 I drilled the compression damper holes larger and used 20W fork oil, hoping to achieve a similarly great result I had earlier made on a KZ400 twin, using the same formulae. But the fork was harsh. So I replaced it with 10W, which is lighter than the stock 15W, and was well pleased considering the age of the system. On a Vulcan 800A I used to have, the fork was bobbing not unlike what my FZ is doing now; at lower speeds on basically smooth roads, the fork act solid. I replaced the stock 10W oil with Castrol 2.5W and the gain in comfort was amazing, with no apparent loss of control. Not that a cruiser is for hard cornering anyway.
 
BTW, has anybody noticed to colour of the stock fork oil in their FZ-07? Mine was red. I wonder if the PO have changed it before I bought the bike, or if it is likely standard? The reason I ask is that "everybody" complain about the soft ride, but my bike was harsh when I bought it (used) both front and rear. It rides softer now than stock.

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Mine was red as well. Idk if it was the previous owner or not. I've heard of some people using transmission fluid in the forks, maybe it's that?

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Thank you for your comments, much appreciated. I prefer the Silikolene oil for its very high VI (464) and will try a straight 13.6 first - I can always suck some out and mix in a little 5W to get to your recommended 14.75 later if it feels too soft. 
I have adjustable retainers, just waiting for the missing top plates to arrive so I can fit them. With static sag of around 40 mm and the fork oil set to 130 mm with the DDC valves in place, my fork will bottom out under hard braking on smooth ground. So I will need to add more preload. Or fit stiffer springs.
 
I feel the bike could actually use a bit more rebound even now (fork oil mixed to approx Cst 18) when I change directions rapidly over roads with big undulations that in extreme cases can become like that the picture below, but that's not the norm. And the simple solution is simply to slow down :D
 
 

I would add rider weight being a big variable, your springs may be needing changing, I'm 180 in full gear and kept the stock springs for my result. There are a many variables to consider, but my advice from experience with the DDCs is to at least stick with the recommended oil viscosity, and play with oil level (Cogent recs. 150mm headspace), and preload. All given your springs are correct for your weight. 
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lots of oils come in red. Yes the OE is red, if it's not gray from filth. So is that chestnut from the 70's - ATF.

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Thanks again. I'm 220 with gear on BTW. The strange thing is that sag without me and with me suggest that the springs are correct, but they still bottom under heavy braking despite the elevated oil level. The rear spring on my Nitron is also soft, so I'll add some preload to the front until it no longer bottoms. At first I had way too much preload and it was harsh as hell, but I did like the handling better with the raised front end, especially around low speed hairpins.

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Is it possible to get good track handling and still not feel harsh on crappy roads? I'm starting to think no. My ktech and nitron suspension felt great at the track, but street riding is harsh on crappy roads.

Craig Mapstone
Upstate New York

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track riding is easy on suspension actually. the surface is smooth. the part that's working hard is the spring and only because you're putting a lot of weight transfer into it. Oh and the rebound circuit as you transit side to side and fore/aft.
 
Crappy roads impart heavy flow (and thus pressure) spikes into the compression circuit. Many suspension systems have too much comp damping (I have a small cottage industry fixing Andreani and Matris kits) but that said, I would first check your rebound settings and see if they aren't too tight for road use.
 
@faffi, your zip-tie is telling you all the travel is gone? What are those sag numbers? In your case you may need a stiffer spring and less preload to stay off the bottom.

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Yes and no. It depends on your wallet and how hard you ride. If you spend 10,000 dollar on suspension bits, I reckon they can be both supple and good for track riding. But you do come to a limit where you need to compromise, regardless of how costly the suspension bits are and how fine they may work. Springs must withstand bottoming. The harder you brake, the harder you change direction and the faster you corner, the stiffer the springs must be. You can still have sensitive suspension with little stiction that will make things as good as they can be, but there is no way Rossi could race with street worthy spring rates, I believe. But for us with more mortal speeds, I think you can achieve a pretty respectable ride both on track and on the road with the same suspenders.
 
For starters, you can alter preload and damping on the Nitron, and I would never have believed what a few clicks on the damper made on the ride. Not sure if you can alter preload and damping with the fork kit you have, but if so that should also allow for a very big change between full soft and full hard. Otherwise, you are back to a compromise setting unless you want the replace the oil every time you change environment. Since I do not ride on tracks, I can focus solely on the road. But there is no doubt enough adjustability to cater for both in my Nitron shock at my mediocre level.

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Yes, my zip-tie tells me all travel is gone, pattonme. I have virtually no preload now (5 mm) and 40 mm of sag measured how Dave Moss measure it. If I pull the wheel clear off the ground, compressing the top-out springs, I have 48 mm of sag with me sitting on the bike.

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track riding is easy on suspension actually. the surface is smooth. the part that's working hard is the spring and only because you're putting a lot of weight transfer into it. Oh and the rebound circuit as you transit side to side and fore/aft. 
Crappy roads impart heavy flow (and thus pressure) spikes into the compression circuit. Many suspension systems have too much comp damping (I have a small cottage industry fixing Andreani and Matris kits) but that said, I would first check your rebound settings and see if they aren't too tight for road use.
 
 

According to RaceTech, race bikes need more compression and less rebound damping than street bikes. I wouldn't know, but their logic seems, er, logical; the extra compression prevent the bike from changing its level rapidly by slowing down the compressing movement, whereas light rebound allow the wheels to track the surface. They also say that most riders want more rebound than ideal because it gives them more feel.
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Good info guys.
 
My rider sag is 30mm front and back. No room to go softer. I think I could use softer springs. My zip tie in front is no where near bottoming. Maybe another 30mm of travel left.

Craig Mapstone
Upstate New York

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 I have virtually no preload now (5 mm) and 40 mm of sag measured how Dave Moss measure it. If I pull the wheel clear off the ground, compressing the top-out springs, I have 48 mm of sag with me sitting on the bike.
5mm preload on fork springs is not unheard of. Pulling the wheel off the ground is the ONLY way to get the full extension number and it compresses the top-out 3mm or so (perhaps less). Those springs are very, very stiff. Getting 48mm rider sag means your springs+preload combination is WAY off. But we need bike sag (no rider) to identify where the problem lies. Since you're bottoming out, I'm going to finger spring rate in abstentia. 
Aim for 20mm sag bike only, you should get an additional 10-15 when sitting on it. I personally wouldn't exceed 40mm. On the rear take the same numbers, but subtract 5mm from bike only sag and maximum value.
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As I mentioned, Dave Moss never hoist the wheel and claim that figure is wrong. I am no suspension expert, but I reckon he is. I get 8 mm more lift by hoisting the front wheel. I compress the front end 16 mm without gear, so likely 18 mm with all my gear on.

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I would listen to Matt @pattonme, he has more experience with forks, and specifically the FZ07 than most anyone here or probably anywhere. i would have bought his custom fork inards except, The shipping and install time (no tools here), was not practical for me here in Asia.
I have listened to a lot of Dave Moss stuff, he has a wealth of knowledge, but if you watch a lot of his videos, he is sometimes unclear and contradicts himself. Not to say he is not very informative on the basics, just he has forgotten more than most of us know, and forgets to explain the details, and of course opinion is always optional.

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