The 996 forks are on my S4 they have improved the handling massivly over the standard forks but .......the bike is a road bike used on very bumpy roads so a plush fork is needed .
what is the standard nm weighting of standard 996 fork springs ? 8.5nm 9.0 nm or 9.5nm as the springs in mine are way too hard i have them set on ZERO preload and forks still to hard oil is 7.5w and 140mm airgap
compression set at 4clicks and rebound 13 clicks bike handle fine but crashes over bumps seems to me and others who have tried the bike that springs are way to strong ????
bike has Ktech revalve kit and possibly Ohlins springs supposedly 9.0nm but i have my doubts about what spings are really in the bike I do have a set of standard 996 springs .
Are you sure it's the springs, and not the oil level or the midvlavle's compression flow restriction causing your troubles?
What is the oil level currently at (how much air gap, with the forks fully compressed, between the oil and the cap)?
If you were to wheel the front end of the bike onto a regular drug or department store scale (with you on it, in your normal riding tuck), what would the scale say?
Another question - what is your static sag without you on the bike, distance between full unloaded and load of the bike only, and what does the front end weigh using that dime store scale, again, without you on the bike? This will tell you your real spring rate.
We're neglecting the topout spring here, but it's an SBK fork right? Topout spring should be short and stiff, i.e. negligible.
The spring alone should not make the forks sooo harsh....
BTW - when you're trying to figure out your stiction, spring rate, etc., it's best you test with your clickers full soft
I've got about 0-3mm of stiction on my forks with compression and rebound full soft, depending on the sunspots, moon phase, atmospheric pressure, and many other irrelevant metrics. At my normal settings, my stiction goes to ~20mm...
oil air gap is 140mm it was only 110mm from ktech after the rebuild , when i told them how harsh the forks are they said raise airgap so i drained some oil , static sag is 12mm .
preload is zero ,fork spring appears to be 9.25nm on local ohlins agent test rig test rig .
the invoice from Ktech says the springs are 9.0nm but i dont believe it as the preload is now set at zero , I did actually ask for 8nm springs but they said they would be too soft , now i am not happy with this situation as the front end is painful ,I did try some hyperpro 8.5nm progressive springs but they made the bike dangerously unstable at high speed so linear springs seem best , just need softer ones .
if i can source some 8nm springs from somewhere i think it would be worth it
the compression and rebound damping circuits work very well the bike is fine of racetrack smooth roads but in real world its nasty
when a customer spends $800 on a revalve and spring setup you would think they would build it to the spec I require????
According to Race-Tech stock 996 springs are 1.0kg/mm
Depending on your weight you could go anywhere from .8 to .9 on a monster.
My experience is that ride harshness is generally a function of damping more than spring rate.
I think your stack needs to be modified.
How much do you weigh?
A useful conversion - 9.81 Newtons to 1 Kg (at sea level :) ), so 9.25N/mm is ~0.94Kg/mm
Yes, not to get too personal, but what do you weigh? I won't judge you by it... I promise!...
At my ~210lbs, on a watercooled Duc, ~0.90Kg/mm on the front feels nice to me on some pretty gnarly road surfaces. On the track, I'd add 0.05KG/mm easy, maybe 0.10Kg/mm... But, if you're wrists are not happy (not to say you're gripping the bars too tight... no matter how hard you try, if the bars are all over the place, your grip gets tighter and your wrists hurt more... just plain instinct...), drop some... My experience, around 0.85~0.95 Kg/mm, the springs are actually too soft for hard track use, but seem very harsh for road use. This isn't actually the springs, it is the damping...
The Showas are pretty well damped, actually, relatively speaking... VERY well damped, to be honest... But if you don't like the damping you'll have to find your way through the mess... If you can find a good suspension guru, they'll help you through it, including softening the shimstacks for your weight/damping needs, lowering the shim thickness from 0.15 to 0.1mm on the first two to four shims in the stack on both compression and rebound, to match your lowered spring rate, etc...
Most important though, what are your complaints.. just how exactly is the suspension working well for you... what are you not complaining about. What is the good, along with the bad?
as of today i weigh naked 73kg (161lbs) so in gear lets say 175lbs the bike had a new Ktech shim stack put in with the new springs specially set up for my weight and i wanted and specified a soft ride due to the roads in Thailand , i did ask for 8 or 8.5 springs but the ones thay put in are 9.0 and when tested recentlky by local ohlins agent on his test rig they were 9.25 so it seems they failed me for $800 work , unfortunately there is no one in Thailand who can work on these forks so if i want more work done on them, its back to UK , not convieneient or easy .
to be honest if i can source some 8 or even 8.5 springs they are not much money $100 it would be the best option to experiment , I am happy with the adjsutment and sharp accuracy and the very precise adjustabilty of the KTech valve stack , just the fact that the nike is on zero preload and too firm makes me think the springs are too hard .
I asked ktech by phone why they put in 9 springs instead of 8 or 8,5 as they list them , they said thay dont have stock , neither do ohlins , so although companies list them they seem rare .
At your weight I'd use .85 springs.
How about race-tech?
Quote from: ducpainter on December 05, 2012, 07:08:12 AM
At your weight I'd use .85 springs.
How about race-tech?
I will give them a call .i still reckon ,80 would work best here as the roads are seriously naff also the bike is more of a sports tourer now than balls out bike comfort is priority
The OEM Monster S4 springs are ~0.85.
IIRC, they're a good bit longer than the SBK springs, but shortening the spacer is easy.
Quote from: Speeddog on December 05, 2012, 08:04:02 AM
The OEM Monster S4 springs are ~0.85.
IIRC, they're a good bit longer than the SBK springs, but shortening the spacer is easy.
Aren't they progressive though?
Quote from: jerryz on December 05, 2012, 07:18:12 AM
I will give them a call .i still reckon ,80 would work best here as the roads are seriously naff also the bike is more of a sports tourer now than balls out bike comfort is priority
I live in NH. Our roads aren't known for quality. .85 works for me, but try the .80
I still think the guys that built the forks used too aggressive a stack and you need to 'soften' it up.
Quote from: ducpainter on December 05, 2012, 09:32:58 AM
Aren't they progressive though?
I live in NH. Our roads aren't known for quality. .85 works for me, but try the .80
I still think the guys that built the forks used too aggressive a stack and you need to 'soften' it up.
S4, S4R, S4Rs and S4Rt all have linear springs.
Not sure what the Rs has in the Ohlins, but the others are ~0.85.
+1 on a too stiff stack.
My limited knowledge of the K-tech is that all of the compression damping is in the base valve.
I keep forgetting you have the K-tech's - I've read really good things about them.
I hear you on spending $800 already though, I'd definitely be a bit miffed having spent already some good money and not getting what I wanted out of it.
RaceTech should have down to 0.85Kg/mm, I've picked up two sets of 0.85's for different bikes and they both showed up at my door right away. Perhaps they can source lower rates on request?
Definitely I would rebuild the shimstacks lighter if swapping out to lighter springs and having trouble with a rough ride - the adjusters primarily control your low speed damping, the shimstacks have much more of an impact on the high speed damping:
- during bumps and sharp impacts, damping force will be dominated by the high speed compression valving
- with a lighter spring, there's less rebound force from the spring itself, rebound damping needs reduced across the full suspension velocity range
It wouldn't hurt at all to try the spring change alone, but I think you'd get a lot more out of the forks by getting into the shimstacks.
I know international shipping to send the forks off for work gets costly and time consuming and import/export paperwork can be rough to deal with, and it's definitely a bit of a commitment digging into the shimstacks yourself.
If you dig in yourself, you'll learn a whole lot from the experience. I'd do some research, from K-tech, from here and other forums, from anyone and anywhere I could. Otherwise it's pure guesswork. Just like when adjusting the knobs, big changes you could make the suspension worse, even unstable, but go slow, iterations of small changes each build, test ride with caution, and it'll be all good.
[beer]
I spoke again to one of ktechs main technicians , and he says that it does seem that my forks are not working properly and that the spec that i asked for was probably not delivered ,(issues with the ex staff member who prepared my forks)
I may be able to modify the shim stack myself if needed but he also said a much softer spring was required ,and we are trying to source an .8 also lithter oil ,it seems that 10w oil might have been used , there is no way i can get these forks back to Uk for at least 5 months as they have to be carried in my luggage ,in and out of thailand if i ever want to see them again and I am off to work next week anyway ,
oh well its an on going project
Quote from: jerryz on December 06, 2012, 12:39:07 AM
I spoke again to one of ktechs main technicians , and he says that it does seem that my forks are not working properly and that the spec that i asked for was probably not delivered ,(issues with the ex staff member who prepared my forks)
I may be able to modify the shim stack myself if needed but he also said a much softer spring was required ,and we are trying to source an .8 also lithter oil ,it seems that 10w oil might have been used , there is no way i can get these forks back to Uk for at least 5 months as they have to be carried in my luggage ,in and out of thailand if i ever want to see them again and I am off to work next week anyway ,
oh well its an on going project
I am about 62 kg without gear,and I use 8.0 N/mm springs in both my Öhlins forks and my modified Showa (Part No 4745-80); preload is about halfway in (a bit more for track days, a bit less for road use). I've tried 8.5 N/mm springs but they were definitely too hard and are now in the forks of a friends 900 SSie; I suppose he'd be about 70 kg. I think 8.0 springs would be on the soft side for you.
You must have had bad luck with the person doing your shim stacks, my K-tech stacks have all worked very well. I agree with the opinion that your forks seem far to "stiffly" valved.
Assuming you have Showa SBK forks, Öhlins R&T springs will fit as far as diameters go, but you would/ might have to manufacture spacers to compensate for the short Öhlins springs. They are available from 7 or so to 11 or so N/mm in 0.5 N/mm steps. Very handy.
I'm glad you're getting some support from K-Tech, let's hope they carry through for you.
Given the long lead on getting the forks back to UK, don't be afraid to dig into the forks yourself, especially if you're getting the support you need from them - if it was me, given 5mo of harsh ride, or a week of the bike down while I get around to doing the work, or not ride at all ( :o ), I'd dig in... Just make sure your workspace is clean, pristine sort of clean - unimaginably small little hairs of thingys in between the shims in the stack make them behave a bit different... Outside of a very clean workspace, I "pressure" wash all of my shims off with brake-cleaner right before putting them in the stack on the rod, just in case.
IMO, suspension in and of itself is an ongoing project - personally, no matter how hard I try, I just can't stop mucking with mine... In my experience, once you dig in there, you just can't stop [laugh]
Best!!!
[beer]
HPD and frankenduc
thanks for the support
I agree that suspension is an ongoing thing ,
my going to work today has been delayed until monday so i took the opportunity to go back to ohlins agent in bangkok as he had found some .85 springs from some spare 916 forks
we swapped them over but checked them on his test rig they were actually .86nm we kept the same oil which 7.5w as its clean and the 130mm airgap and also we wanted to do one step at a time , he did notice that the forks seem a little reluctant to move stiction ??? but all is perfect mechanicly , bushes ,stanchions seals all perfect alignment so he thinks perhaps the ktech shim stack might need adjustment for a lighter action but we will leave that for now , he is interested in stocking the ktech products in future , we need some research and advice from ktech before we go there though .
he also thought that a slightly stronger rated rear spring in my Ohlins PRCS46 shock might be in order in the future as he noticed i have it set with max preload , although the rear end is nicely set up for me solo it could be a good idea especially when touring with sabblebags or a passenger .
he is helpful to me as I have done him a favour or two in the past on his 999 racebike vis a vis
fuelling maps and valve gear setup and he is a genuine bike nut .
any way we did a test ride and after dropping the compression damping to only 2 in and rebound to 7 in from minimum the bike felt much nicer over bumps/ imperfections and more stable too ? , still Zero preload which is weird but riding the 70 miles home was better ...not perfect ......perhaps lighter oil might help the shim stack respond better 5w? 2.5w???
spoke tonight with ktech technical in Uk , the guy was concerned about the Zero preload and the fact that i am only getting 22mm sag he said it should be 25-30mm,
he also said that Ktech actually reccomend 5w oil, so he is suprised that it is 7,5w ?
tommorow i will recheck the sag yet again , he think that the issue is not the shimstack at all but there is something very wrong in my forks if they are on Zero preload !!!
anyway still may look for .8nm spring as well but next step will be to get some Motul 5w oil
cheers jerry
Rad, you got a helping hand out there [thumbsup] Glad to hear!
Be careful with oil weight, it's not really the oil weight that matters, it's the viscosity. Viscosity varies between brands (same weight label), and also with temperature, so your tech may have chosen a 7.5w of some brand to get the right viscosity, maybe because of the warmer climate, maybe just how viscosity works out for that brand, so on.
I don't know the K-tech's, or your stack setup, so can't say how they'll respond to oil viscosity changes. Assuming the valve throats and stack setups are not too restrictive, changing oil viscosity would impact the low speed response, braking and acceleration primarily, some to bump response but not as much. However, more restrictive valve throats and/or shim setups would see more of a change in damping over the full suspension velocity range from a viscosity change. Worth playing with, oil's relatively inexpensive, just bear in mind it's hard without knowledge of the valving to know what it'll do.
for stiction/binding concerns, with the front end off the ground and supported, you can loosen both fork caps, and slide the whole wheel assembly up and down in the fork tubes, it should move smoothly and freely with minimal resistance throughout the range of travel.
Also, you could check sag and stiction again with all of the clickers wide open - I have maybe as much as 3mm with clickers wide open on my Monster, but clickers at my current ride settings it looks much larger, maybe 15~20mm, I've never measured but it looks big! I have a lot of low speed damping on both compression and rebound, which limits slow suspension movements like those during a stiction and sag checks.
for sag/preload, this is 22mm difference between fully unloaded (front wheel off the ground) and loaded with you in standard riding tuck?
If so, it sounds like the spacers are too long for the fork springs. That's an easy one to fix, take any extra spacer shims out (don't remove the steel washer than goes betweeen the spring and spacer/shims), and if more sag is needed just cut what you need off of the spacers. It's more difficult to fix too much sag, unless it's a small amount and can be safely shimmed up, so err on the side of cutting less.
IMO, for road, 25-30mm sag even seems quite low to me.
Assuming you have some sag at all, preload sets the useful ranges of compression movement verses rebound movement. Assuming you're not bottoming out on the front side of bumps or topping out on the back side of bumps, it shouldn't affect ride over the bumps. It is a trade-off
- smooth track where you want as much useful compression range to handle the heaviest braking loads, lower sag works, towards 25mm for the smoothest tracks. During braking as much as the whole weight of the you, the bike, plus the deceleration force all act to compress the forks, so more compression range means higher deceleration force can be achieved before bottom out.
- rough roads, having rebound range available to allow the forks to extend to keep the tire on the road on the backside of bumps, dropoffs, potholes, etc., seems a useful thing.
I've seen/read/heard a lot of different recommendations, as high as 45mm for streetbike road use. My target is, with ~110mm useful travel, 35mm sag for everyday road riding, or about 30% of useful travel. So I set my front 35-40mm preload full out, and I can turn it in for smoother surfaces.
For neutral chassis balance, set rear sag to match front, so seems like you could turn the rear out some. Still doesn't mean the spring rate is right, so very much worth looking into (think Ohlins is kind enough to have this printed on their springs, so maybe if you look :) )
There is one further hint the sag numbers can give you; if you check the difference in empty sag and rider sag, it will give you a hint if the spring has the right rate for you or not.
For trackdays I run empty sag 20 to 30 mm front and 5 to 10 mm rear, and rider sag 35 to 45 mm front and 20 to 40 mm rear.
In other words, 15mm difference front and 15 to 20 mm difference rear is about right. Less than these number indicate too stiff springs, more indicates too soft springs.
For road use, you'd go for maybe 10 o 15 mm more sag front, and maybe 10 mm more sag rear, but with the right springs, the difference will still be the same, i,e, around 15 to 20 mm. Remember also, the difference is not affected by preload.
Seems these numbers are about the same as those stated by Frankenduc.....so probably [thumbsup]
Oil viscosity is measured in centistoke (cSt), which is a unit for which I have no feel at all. The 5W and so on numbers are also viscosity numbers, but more alluding to the known engine oil viscosity grades. I do not think there is a standard defining what a "5W" oil really is and as a result different brands can vary.
The Öhlins oil specified for their R&T forks has 19cSt @ 40°C; for the BelRay oils I've been using this is a little thicker than their 5W, but considerably thinner than their 7W but I don't remember the exact numbers. Usually, you can find these numbers somewhere in the manufacturers documentation, or you can ask them for it.
I do not think most of us would notice the difference between 5W and 7W oil, but I use the thinner oil since it will change less with temperature, or so I believe, at least ;)
I carefully rechecked front sag today and i have 32mm from forks fully extended on stand to rider sitting on bike so seems about right , still with Zero preload ,,,,Ktech recommend Motul 5w Factory line fork oil for all the forks they set up or manufacture , and remember they service most of the MotoGP teams so they know a bit about oil .I cant get motul factory line in thailand only motul regular fork oil but will get some in UK.
oh my front pirelli diablo corsa is nearly all used up so a new tyre may also help matters
will go for Dunlops next time either Q2 or Roadsmarts , probably put a new rear on as well to match but a set of decent tyres here is $600 unless one wants shinko then its only $200 a set but are they any good ???///?
looks like i am going offsghore tuesday for 2 months then to UK so this will all have to wait
cheers jerry
Quote from: jerryz on December 08, 2012, 06:45:02 AM
I carefully rechecked front sag today and i have 32mm from forks fully extended on stand to rider sitting on bike so seems about right , still with Zero preload ,,,,
Sounds about right, even if it's a bit strange you're not having any proload (not knowing what the installed preload might be).
It would still be interesting to see what the difference between sag under bike load and sag with rider is, to hava hint if the spring rate is about right.
sag with no rider is 22mm with rider 32mm, there is no installed preload spacers all preload is done on adjusters and they are fully wound out
Quote from: jerryz on December 08, 2012, 07:28:43 PM
sag with no rider is 22mm with rider 32mm, there is no installed preload spacers all preload is done on adjusters and they are fully wound out
OK, seems to support the opinion you already have that the springs are too stiff.
Quote from: MonsterHPD on December 09, 2012, 01:23:34 AM
OK, seems to support the opinion you already have that the springs are too stiff.
my thought exactly but still cant find any one who has .8nm springs in stock
tried Ohlins ,Ktech , hyperpro ,hagon ,ducati and Maxton all only supply 8.5 or progressive springs and racetech who list .8 spring never answer emails from USA or UK ?????
will keep looking , springs are cheap so i dont mind trying some
Well, as discussed earlier, I finally resorted to using Öhlins R&T-springs for exactly that reason: Could not find 8.0 N/mm springs thyat would drop right in anywhere.
Making the new preload tube was not much trouble as I have access to a lathe, but I suppose it would not be that costly to have them made either.
i will speak to my ohlins agent ,
Fine.
This pic has been on the forum before, but this is what it looks like:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Springcomparo.jpg)
sprung weight on the front end (bike + rider) and spring rate determines ride frequency, or ride firmness vs. response. More firm is the trade-off you give for faster suspension response (i.e. more time of the tire on the ground, and thus more traction).
There's a couple of things here that matter here WRT sag, that is installed preload and total sag (bike + rider + gear and all). You're tuning sag to get the desired range of available travel in both the compression and rebound direction,
1) more sag, more rebound travel to soak up potholes
2) less sag, more compression travel to soak up bumps and braking forces
So, take this as... the harder you are on the brakes, the more compression range you need...
And installed preload to get a baseline compression range.
1) the harder the spring, the more braking force the suspension can tolerate (before doing something bad like hitting the oil lock, where the forces on the tire just make it give up...)
2) the softer the spring, the slower and the softer the suspension response, and less time the tire spends on the ground creating this thing we love called "traction"... but then, the less the bike tries to buck you off of it...
I've currently got my forks, for road use, tuned for the bike+rider load only,. i.e I take the load the bike and I, rear wheel totally off the ground, 245Kg's load
- this force should just push the forks to the oil lock limit. that is, for my Monster, ~245Kg's, if held constant (i.e. damping aside) should compress the forks from fully topout to ~the oil bottom-out lock level. (discounting air spring and assuming sustained load)... At this level, braking forces push it over the edge, so I can only brake so hard on the street...
For track use, you're going to be (hopefully you let yourself) much harder on the brakes, [and of course the road surface is much smoother], so one or both of two things need to happen:
1) sag set much higher in the full stroke - that is, you give more travel to the compression side to handle the braking forces, and you assume you need less rebound travel due to the smoother road surface
2) spring set much firmer - the higher ride frequency of the stiffer spring helps you keep the tire on the ground more of the time, ie. more traction. Additionally, the stiffer spring reduces your travel on load, further increasing the braking forces you can apply before bottom out.
Anyway, I've taken a very roundabout and [trying to be diplomatic] way of saying this - bike static vs rider load is going to vary with the rider's weight, regardless of the sag setting's aggressiveness...
At your 0.86Kg/mm current spring rate, and your 22mm bike only, 32mm you+bike, that makes you an added 17Kg to the front of your bike (surely you weigh a bit more than 17Kg... but that's all you're loading the front with...)
You bike is, I'm going to guess, ~85Kg on the front and ~180Kg total.
If you strive for 15mm static vs. rider sag, you'll wind up with 0.56Kg/mm springs... which will in fact lower your ride frequency into the range of that of a Lincoln Town Car - very nice and plush... But will also not give you much margin at all to brake hard...
I get away with ~15mm static vs. me sag because I'm borderline obese for my size, and it works, I can just bottom out my suspension with the oil level nice and low... But at my weight I'm also a substantially larger portion of the front end and total weight of the bike.. ~25KG out of 96Kg for the front, and ~96Kg out of 245Kg (don't forget to leave the 40lbs unsprung weight of front wheel, brakes, etc. out of the equation...).
I don't know the exact weight of the front end of a watercooled S4, but I think you can get down to 0.8Kg/mm safely, and enjoy it very much for regular spirited country rides, but I wouldn't go much lower than that.
[beer]
Frankenduc , wow you must love posting a lot of hard work there ...thanks , actually when braking my bike dives in a very contolled manor , and not much either ,
still at home so will go for a run tommorow , may even go down to Cambodian border thats a round trip of 600 miles ,cant do much to the bike until I can source some parts , in UK
[laugh] I'm in rapid fire documentation mode for work right now, I appear to be taking it home with me
Think you've got the right idea though, less talk and more ride [thumbsup]
No need to be diplomatic here, we're just trying to find the best starting point for choosing spring rates.
I've also been down the route trying to make sense of static and dynamic loads etc, but at least for me some basic professional advice when I bought my Öhlins fork ("use 8 N/mm spings ..."), and what has proven to work on trackdays as well as road riding, was the quicker route.
Of course one can not match a precisely defined bike sag with a precisely defined rider sag when the bike weight is pretty constant and rider weights vary, sometimes wildly, no matter what spring is used.
However, juggling spring rates and pre-load and working with sensible ranges for the sag values mentioned has proven to give results most people are happy with, if only because what they had before was wildly off. Really quick riding might require a more scientific approach; I'll probably never know first-hand ;)
That said, your thoroughness, Frankenduc, really impresses me. I've done a lot of thinking about this and related things, but I think you take off where I let go :)
Jerryz, sounds like you have some interesting riding surroundings, and not least, climate. It's -8°C here now ..... have a nice trip!
HPD and Franenduc what do you guys do for a living , i wish i was less isolated here but i do spend a few months of the year in Uk riding my M750 and 750ss there , thaty have nonadjustable forks and work fine ,amazing as the s4 has fully adjustables and all they do is pose questions .
i have often enjoyed riding in California and oregon in the past
Quote
HPD and Franenduc what do you guys do for a living
;D
I spend too much time at work, really. Maybe I should sleep some more :-\
had a bit of a breakthru today , my friend Dom came down from Bangkok on his hyabusa , he brought some 5w motul factory line fork oil so we drop the forks again and changed the oil
so bike now has .85 spring 5w oil , whilst we were putting it back together I was stuying my extensive notes from over 7 years on modifying the nike when I noticed an anomaly ......doh!!!!! ,BUT what i had forgotten was that I used to run the Old forks 15mm lower thru the forks for better turn in , but they were so flawed in damping that i eventuall replaced them with the modified 996 forks after 5 years.
the old Standard showa S4 forks were 15mm shorter than the 996 forks so when i fitted them i set them 15mm thru the triple clamp plus 5mm= total 20mm but the bike is sitting 10mm higher than i liked it before ( so I have had a massive brain fart) no wonder there may be not enough weight over the front whell and also trail is too much so turn in will be heavy .......DOH!!!!
any way we set the forks another 10mm lower so in reality the forks are -15mm now , to compensate i reduced rear compression also by 2 clicks
The rain had stopped so we went for a 50 mile ride after 10 mies i stopped for gas an felt that the bike was much nicer especially in the turns at all speeds , no running wide or understeer very flickable not like before , also front felt like it needed mor rebound so 2 clicks more now 12 in compressionwas upped from 2 in from softest to 3 in and i put 2 turns on preload
we rode on and the bike feels much better , the 5 w oil has helped a lot ,i can feel every thing the tyres are touching front and back also no slides from the rear now at all even on wet roads.
the only negative is high frequency vibrations on the handlebar thru the forks , not engine related I have gel grips but may be need heavier bar weights ????
so a basic error by me on geometry has been blighting the bike ........IDIOT ... forks may still benefit from damping or spring change as i think they could be a bit more compliant or is it the handlebars ???
cheers jerry
Nice to hear you got the fun back [thumbsup]
I did same sort of thing when I installed my Öhlins which are also longer than the stock Showas and the bike steered like a shopper. Pushing the fork legs up through the triples cured that, and I also run the fork legs some 10 to 15 mm lower than stock and the bike steers quite OK.
This morning I picked up some really heavy nicely finisged Stainless Bar end weights the old ones were feeble a few grams thes boys are 2 oz aboy 60 grams each , made a big difference to the vibes ,
no rain today so gave the bike a real test. thrashed her hard on my favourite roads , steering is perfect , can lay the bike over at extreme angles and flick side to side, tracion good ...awesome
Bad is that .low spped damping is still a little harsh BUT high speed above 60 mph up to 130mph the suspension is perfect even on very bad roads .
tarmac roads are pretty good but washboard style concrete roads are a little bouncy until over 70mph then they get a bit more tolerable
not sure how the damping circuit on Kspeed valve stack works or the 996 or wether more can be done to dial in the low speed damping ???
front tyre is nearltt finished so that cant help
a great day out today 80 miles of perfect biking
nice to hear!!! [thumbsup]
So, yeah, you're probably a little tight on the low speed damping, which is not necessarily a bad thing at all - if you can tolerate what it does. It helps you with brake dive and squat under heavy acceleration, deep in corners the bike stays on its line way better no matter what sort of nasty things you're doing on the controls... You can change that pretty directly with the compression clicker. Having a lot of LS compression damping does make a pebble on the road more noticeable though, and IMO as long as I don't mind that and it's not bucking me off the bike it's all good.
The higher frequency stuff is probably due to running your clickers nearer to closed and overall having higher low speed damping - you could make that go away, but it's sort of like one of those relationship compromises... Although, I did come up no too long ago with a midvalve compression shimstack that, in conjunction with the other stacks in my forks, would cause a small wholly undamped oscillation at a certain frequencies (~2-3Hz) if perturbed the right way... I could lean off the bike and watch it, the wheel would never leave the ground and it would never happen under cornering loads so I thankfully always had very good control, but eerie still. If you notice something bumping you at a constant rate while you're on a smooth road, it's probably good to take a step back and look at it [laugh]
How are the bar ends working out, do they help?
I've got GXSR forks on my Monster, they're longer than stock by, oh, an inch or so, I drop the front a good half inch or so triples to forks and raise the rear about the same to get the turn in I like. Maybe a little higher on the front than the rear for me. Love the extra ground clearance. You can do the similar for turn-in/stability with preload, turn down the front some or up the rear some to get quicker turn in... Opposite makes you push a little harder to keep it leaned over, which gives a little more of a stable feel.
Quote from: MonsterHPD on December 11, 2012, 02:40:37 PM
I spend too much time at work, really. Maybe I should sleep some more :-\
Concur!!!
I'm an Electrical Engineer, for many years I did a lot of analog closed loop control system designs at chip and board level - power supply/conversion, PLL's, test and measurement - and loved it. That's probably why I enjoy to wholly and completely overthink on suspension - it's open loop, discounting the rider's inputs [laugh] but still a control system. The mechanics are vastly different and not what I'm used to (kind of wish I hadn't slept straight through Statics and Dynamics in school), but the concepts are still very much the same. And control.. Who doesn't like it ;D
[beer]
I couldnt have found this thread at a more helpful time, but I really dont want to thread jack here... So Ill wait for someones go-ahead before drawing the thread to my own questions... [thumbsup]
Quote from: freeclimbmtb on December 19, 2012, 09:17:00 AM
I couldnt have found this thread at a more helpful time, but I really dont want to thread jack here... So Ill wait for someones go-ahead before drawing the thread to my own questions... [thumbsup]
Fire away!
Not the OP...but Ill take it. ;D
Right now:
Bike: 2011 Monster 796, for this discussion call it stock. (except clipons which affect weight bias, and call it 10lbs of shed weight)
Rider: 5'6", 132lbs in street clothes...say 147 in gear.
Changes to be made when the triples arive:
Ohlins from an 1198R (stock forks to the best of my knowledge), 1098/1198 brake/clutch controls, IMA special parts full replacement triple trees and adjustable clipons.
Heres why:
I'm a skinny guy. Ducaticant possibly have had someone smaller than me in mind when they built the 796, yet I've bottomed the forks out on potholes more than a small number of times in the last 12k miles. It dives super hard on hard braking, and just genrally feels crappy. Ive even had friends comment that my fork is always moving, yet when they sit on it are in disbelief as to how short the range of travel seems to be.
NOW... based on what Ive read above, a 8.0 N/mm spring should be about right, (at least for street, perhaps an 8.5 for track?) Ill deal with the rear later. But thats about all I can contribute to setting it up. (owing to lack of experience, not lack of understanding...I learn more by doing than reading) I dont know what to do about valving or oil, or really even where to start with rebound/compression adjustment. (a product of having always been on a non-adjustable suspension.)
The up/down side...Ive got plenty of time to get the project done in the winter months, but no way to test/tune until the weather changes.
You're on the right track with the 8.0 spring.
I suspect you'll want to soften up the valving.... but not having the forks in my hands, that's just a suspicion.
I recommend staying with the standard Ohlins fork oil, #1309.
I *think* those forks will take the 04745 series springs, but verify prior to buying....
Ok. More than likely I will go with the 8.0 springs, I will verify with an Ohlins shop before buy the springs. That should get me to a point where I can at least ride to Boston for a tweak and tune session with the guru down that way.
Now briefly on the rear. I know the DU737 is THE replacement for the sachs unit I have, and Ive heard good things about it. Now, what about a superbike rear end as well? the 796 and 848 share the same swing arm, so is the shock an option as well? (pending clearance issues with the external reservoir)
796 and 848 swingarms aren't the same, 848 has a linkage, 796 is direct-connected to the shock.
I don't think any of the shocks with a piggyback reservoir will fit.
Gotcha. Just looked at a blowout diagram and had the DOH moment.
Quote from: freeclimbmtb on December 19, 2012, 10:47:36 AM
Ok. More than likely I will go with the 8.0 springs, I will verify with an Ohlins shop before buy the springs. That should get me to a point where I can at least ride to Boston for a tweak and tune session with the guru down that way.
Now briefly on the rear. I know the DU737 is THE replacement for the sachs unit I have, and Ive heard good things about it. Now, what about a superbike rear end as well? the 796 and 848 share the same swing arm, so is the shock an option as well? (pending clearance issues with the external reservoir)
There's a guy in NH that is amazing with suspension...just sayin'
Quote from: ducpainter on December 19, 2012, 12:00:34 PM
There's a guy in NH that is amazing with suspension...just sayin'
(http://manscreed.com/wp-content/uploads/2011/12/im-listening.jpg)
Quote from: freeclimbmtb on December 20, 2012, 09:48:50 AM
(http://manscreed.com/wp-content/uploads/2011/12/im-listening.jpg)
pm sent...
Foe anyone that's interested www.clubhousemotorsprts.com (//http://) our own ducvet.