Kawasaki Concours Forum
The C10, aka Kawasaki Concours - The Original => Accessories and Modifications - C10 => Topic started by: Oldspeed on July 19, 2012, 08:32:39 AM
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Been riding with emulators for about 45K....and it seems like the rebound could use a little more control......maybe the reason RT recomends a lower rate fork spring......Has anyone tried to restrict the oil flow through the emulator's rebound side?.... I'm getin ready to attempt a mod but maybe your input can save me the time.
Gotta say it doesn't look to difficult to restrict or return to norm.....Tried heaver oil mix,but returning to 15wt.
I don't post much since the old site went down, Just been riding on and on !!!!
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The rate of the spring is dependent upon your weight and the weight of passenger and luggage. If the spring rate is too low (soft) then your suspension will fall down (sag) too low. The means the geometry of the bike will be wrong (handles not too good) and you wont have full use of your suspension because your shocks are already compressed too far.
Raising the front back up to its correct height is done with those two screws in the top of your fork tubes called Pre-Load adjustors (sag adjustors) but they can only do so much and cannot compensate for weak stock springs (unless you and your luggage and your passenger weighs less than 150lbs total) hence the need to replace your springs with higher rate springs. What rate springs do you have now? How much do you weigh?
Emulators regulate compression or dampening and in conjunction of the thickness shock fluid . Thicker fluid will increase dampening but so will tightening the nut on the top of the emulator.
You cannot change the rebound with emulators. There is no 'rebound side ' on emulators and I do not know who or what RT is.
Rebound is adjusted by using thicker or thinner fork fluid. The thinner the fluid the quicker the rebound.
Are you saying that your ride is too harsh? That is called dampening and that can be adjusted with the emulators. Drill more holes in the relief valve, get softer relief valve springs or loosen the nut out on the emulator.
Also, having too high a level of shock oil in the fork tube will dramatically increase dampening and give you a harsh ride.
More information on 'Packing and 'Pogo-ing' can be found for excessive or lack of dampening and rebound.
I hope that info makes sense. Let me know anyone if I got it wrong.
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Thanks Mike,....Nothing wrong....just thought someone else might have experimented with restricting the flow path on the rebound side of the emulator to gain more rebound control without going to a thicker viscosity oil....IMHO the emulators are a one size works for all and I'm on a fine line of tuning for a little more control on rebound.
I intend to solder small blocks of copper under the area that the fork spring rests..cut at a length to extend over into the rebound flow path
IMHO our use of 1.1 and 1.2 springs overpower the emulators ability to slow the forks extension ( enough to my likeing )...
Again ....nothing wrong with the emulators...trying to make good...a..little better Later, Oldspeed
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I, like you think many have a problem tuning the Emulators due to running too heavy a spring. You might have better results if you replaced your springs with a lighter rate spring.
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There's a great article on emulators here
http://www.sportrider.com/tech/146_9502_tech/index.html (http://www.sportrider.com/tech/146_9502_tech/index.html)
The emulators don't impact rebound damping much. If you want to increase rebound damping, the easiest way is to use thicker oil. With the thicker oil, you should slacken up the emulator compression damping or you will get harsher compression damping too.
If you desperately want to increase rebound damping without changing the oil, you could braze the upper damping hole closed and drill it out smaller. Sure seems to me a harder way to do things.
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I'll be interested in your results. I have the full Racetech setup ( 2 turns on emulators, 1 kg springs, 15wt oil) and think it works as well as can be for the original forks.
There is one corrugated corner near home and if I hit it in the right spot at high speed while leaned over I can feel the front wheel skip which indicates too slow a rebound. A lot of suspension tuners say much of the poor handling they see is caused by too much rebound, so start small and be carefull.
Regards, Russell
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I'll try three restrictions on each emulator.....will re assemble Sat. morn !!!!
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Back together,,,Rain Sat. Sunday morn.....Short Sunday test ride and ...IMHO the mod is a plus!
note.....1.1 springs, Emulators set at 2.0 turns, 15 wt, 4 holes in the blow off plate, plus 3 restrictors out of possible 9
At this time I did a complete fork dis-assembly, clean, new lower bushings shimmed with .0015 feeler guage....and very carefull re-assembly/ alignment.
With the added restriction to the rebound side of the Emulator the fork action feels more oil dampened.
Next fork oil change I may add one more restrictor and fill 2 of the 4 holes I now have in the blow off plate and adjust the emulator to 1.5 turns in.
As with all DIY repairs and mods.........Do this at your own risk!
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Hi Oldspeed,
Interesting. Thanks for feedback.
Your rebound seems to have been quicker than mine, I think I have some of the reasons (just for interest sake).
1) one hole only in blow off plate, (this is how they came out of the packet) - more resistance to oil flow
2) lighter springs (1 kg) - less rebound force
3) my forks are pushed through triple clamps, not much about 6mm from memory - more weight on front
4) I weigh 190 lbs then add riding gear, maybe I'm heavier
Keep us informed.
Regards, Russell
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What are these restrictors you mention? I'm still trying to dial my forks in, its a slow process for me. I've got emulators. Whats your method of adjusting pre-load on the emulators, picking your brain, I follow the instructions included but was wondering if I'm doing it right.
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The top face of the Emulator has nine areas,, Three of which I've filled-in with copper square rod , held in place by soldering. These small rectangles extend over the oil flow path which is above the lower check valve ( rebound valve ).
IMHO the manufacture is going about the tuning of its product to an application within certain limits.... and its OK,, nothing really wrong......
RT concentrates on the pop off ...which IMHO is what we want the least of, ( compression ) ,We want the most compliant fork action on the " Hits" as possible....More holes in the pop off and lighter fork oil, and of course less pre load on the pop off all work to gain a smooth ride...But,,, at the loss of rebound dampening........RT may recomend a lower rate fork spring to tune their product to a certain application,,,,,,,this may be OK for riding up hill,and on the flats........Down hill is the test,,,,,combine with a irregular road surface and braking,,,So IMHO the first consideration is the spring rate to support the vehicle and rider.....At 180 lbs...I tried .90..but came back to 1.1
Back to Emulator........I may keep adding more to restrict rebound..and at the point of too much...drop back to 10 wt. oil and two holes in pop off..........I'm trying to dial in what normally can't be changed....then fine tune the pop off.....I think a better ride is in the works !!!!!!
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OK, this just keeps getting more and more confusing. I just want a smooth ride with a little less diving at braking. I followed the instructions, then found that they say 150mm from the top of the tube for oil level, and Kawasaki says 171mm. I try blue springs, PVC spacers, cutting the stock springs instead of PVC spacers, emulator pre-load, factory pre-load, sag height. Its better, less rigid but not where I think its supposed to be reading all the posts here. I usually put 5-8000 miles a year on the bike, I only got 1000 this year. Just when I think I'm understanding it all, someone throws out something I never heard of, thats why I'm asking about restrictors. Somebody want to ride to Cleveland or maybe I can take a road trip, ride my bike and tell WTF is going on?
-2001-68,000 miles
-200lbs
-.95's springs
-blue springs on emulators-older style emulators-gold-non-scored plate, 1 small hole in plate
-2 turns of emulator pre-load as per instructions, 2 turns in after washer just touching spring
-3 lines showing of factory pre-load
-171mm from top of empty tubes with 15wt oil, measured 5 times after pumping forks then fully compressed
-6 inch PVC pipe spacer
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Keep in mind that I'm altering the Emulator .
Normal RT instructions and other post on this and the other forums give really good info on setting up and dialing in...
I'm goin beyond the norm....
Just tryin to make good thing even better.
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OK, Looks like my Emulators are an old style ( Nine slots )..New type smooth... The newer type should be easier to restrict with thin brass plate.
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Strawboss, You say you just want a smoother ride with less brake dive. I think you need to try more holes in the blowoff plate. You can drill them yourself or order them from RT. I'm running 4 holes which makes it respond quicker to sharp bumps (smoother). At the very least you need 2 holes. As far as spring rate goes I think you might have to light of a spring rate for your weight. I weigh 160 and run a sonic 1.0 straight wt. Your running a .95 and I don't know if thats straight wt or progressive, but I think you need more spring rate for less brake dive. Everything else looks right in your set-up. Use the 171 mm like RT says. As far as preload (3 lines showing) Is that giving you about 35 mm sag when you sit on the bike? Thats whats important to know. You might need more or less preload depending on that sag number. Does this help? Mark
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oldspeed, sorry to yell, but I'm about done. I've had the front end apart more times that I want. Sparkie, RT says 150mm in the instructions they sent, I'll go back and check but I'd bet my ice cream sandwhich on it. Kawasaki says 171mm. And yes, I'm drilling another hole in the plate. I originally had 1.1's as per the web site of a popular vendor here suggested. About shook the fairing off. RT said "gosh, thats way too much spring", .95's are better. What I'm getting now is when I go off a small curb like out of a driveway, it seems like the front end just thrusts forward as if the forks were super sprung and they seem to thunk out, meaning to me, not enough rebound damping. I'll drill the holes tomorrow, I was just holding off doing it. As I said, each time its getting a bit better, I'm at work now and will try this sag measurement thing. 35mm, thats about, what, inch and a third? Thanks, I'm just frustrated.
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OK, sat on the bike, and the forks never compressed, only the rear shock compressed. Applied front brake, pumped the forks, seemed real hard to go up and down, extended the forks, sat on the bike, it went down a bit, stood and sat again, forks never compressed.
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I am just a newbie, but i would like to post here. I must first say, that I am not too smart, nor good looking, but I have a question for Strawboss. Why are your PVC spacers cut to 6 inches? If I recall correctly, ( and that is surely possible), Aren't you supposed to trim the difference of the emulator off of your spacer? I would think,.....( but remember I said I'm not very smart), that this would increase the amount of preload on the springs, resulting in feeling more bumps, and a harsher ride.
I recently installed sonic springs, 1.1, emulators with blue springs, 2 turns preload, and 15wt oil, 4 holes in the top of the emulator, and two extra holes drilled in the dampner per race techs instructions. I weigh about 250 or so, and the ride is a bit harsher than before all of this, but I do not have the brake dive, and it rides a million times better than before.
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Right now I can't recall why the spacers are 6". But, I cut them to 4" and the bike rides way too low in front and I can barely get it on the center stand, and there was no difference in the ride that I could see. The 6" spacers are right even with the top of the fork tube. And yes, I forgot, I drilled the dampers too. I'm just trying to get someone to tell me how long my spacers are supposed to be, I've never been able to extrapolate the info. So what does trimming the length of the emulators off the spacers mean, whats the starting length?. What measurement do I start off with, I've never understood this, I sit and look at the instructions and it doesn't come to me. BTW, if it means anything, the top of my fork tubes are flush with the top of my clamps.
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I don't have the instructions for the sonic springs anymore, but as I recall, sonic springs tells you to cut the spacers to 6". Then, in the race tech instructions, it tells you to trim the height of the emulator off of the spacer. I believe this was about 3/4". I do believe that this difference could cause a rougher ride, as the suspension is preloaded.
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I got everything back home. Heres a copy of pre-load instructions, go to pre-load calculations, yeah right, I get the free length, for me its 6", someone want to tell me how to get set length? Would this be the 6" minus the length of the emulators, which vanjeff states is about 3/4"?
http://racetech.com/download/RelaxedPreloadWorksheet.xls (http://racetech.com/download/RelaxedPreloadWorksheet.xls)
http://racetech.com/ProductSearch/2/Kawasaki/ZG1000%20Concours/1994-2006 (http://racetech.com/ProductSearch/2/Kawasaki/ZG1000%20Concours/1994-2006)
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Strawboss..considering the mileage...could be a worn bushings/fork leg ...causing too much fork stiction........lifetime of bushings...about 20K.
Fork aliignment ? Have you gone through the proceedure of loosening/pumping/tighening ?
Oil height with forks fully compressed...6 in. from top ??
Fork brace ? Make shure its not causing a bind..shim if neccesary.
Keep in mind the weight on the front end can change as much as 40 lbs. between fill ups!!!!
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I got everything back home. Heres a copy of pre-load instructions, go to pre-load calculations, yeah right, I get the free length, for me its 6", someone want to tell me how to get set length? Would this be the 6" minus the length of the emulators, which vanjeff states is about 3/4"?
Ok I think I see the confusion. They are talking about the top out springs. You don't need to do anything with them. They are little short springs on the dampener rod. Try this for me. Turn the preload adjusters on top of each fork cap all the way out. You should see more lines showing. Does that make a difference in letting the forks sag when you sit on it? If so then the spacers are too long and need to be shortened. Does this make sense? Mark
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Strawboss, a couple things come to mind. 1) if you have a fork brace, and it's not METICULOUSLY shimmed, it will cause stiction, and the front end won't sag or even function properly. 2) if you don't have at least 1" constant preload on the for spring, the emulator will unseat from the damping rod and "thunk" when it's slammed back down. I had the same issue when I very first installed mine, so I called RT and they told me the 1" rule. Nothing about it in their instructions though - Steve
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Just say the heck with it and start afresh.
http://www.zggtr.org/index.php?topic=8735.0 (http://www.zggtr.org/index.php?topic=8735.0)
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Fork brace, yes. OK, I drilled another hole in the plate of the emulator, better compression, still jarring rebound on sharper bumps and heave here. I can live with it. I added 5 turns of factory pre-load, when I sit on it now, I get about 1/2 inch of sag using the zip tie on top of the female slider unit, about 3/4 inch all the way out. I think yes there is stiction, not even going to think about how to shim. Now, here's the thing again. RT says 150mm or 6 inches from top, Kawasaki says 171mm or 6 3/4 inches. I have it at 171mm, 6 inch spacer.
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Are you saying you turned the preload adjusters further in by 5 turns? Or did you turn them out? I'm confused. If you added 5 more turns of preload that won't make the front sag more. Mark
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Strawboss, I you don't get the forkbrace right , w/o stiction, you're literally wasting your time trying to set up the front end. The adjustments are all compromised by the stiction, and ultimately you'll waste the fork seals and bushings. BTW, setting the oil height is only to use the remaining compressible air as a spring for the front end. the less air (more oil), the higher/ quicker the pressure rises upon compression. HTH, Steve
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Strawboss,
That sag sounds too little, for racing it is usually around 25mm (1") and for street 30-32mm (1 1/4"). Refer Sportrider article below:
http://www.sportrider.com/tech/146_0308_set_your_static_sag/index.html (http://www.sportrider.com/tech/146_0308_set_your_static_sag/index.html)
If it's any help my '86 has 35mm preload (=175mm spacer length) and 150mm oil level fom top of fork fully compressed. Preload and oil level are Racetech recommendations.
Fork tubes should be flush with top of handlebar mounts.
Regards, Russell
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strawboss, you are setting the fork oil level with the springs out, forks compressed, correct? Steve
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Once again
2001, 68,000 miles
.95's
blue springs
emulators with 2 turns of pre-load from just touching washers on spring
fork brace- one extra hole drilled in pop off plate
171mm of 15 wt oil measured 5 times after pumping forks a few times- forks compressed, no springs, no emulators-empty
5 turns of factory pre-load from all the way out
6 inch PVC spacer-with washers on each side of the spacer
damper rods drilled as per RT instructions
-The fork tubes are not flush with the top of the clamps as some purchase is needed for the Genmar risers I have-so how much should be above the tops of the fork tubes?
-How long a spacer should I have?
I was quite happy with the stock set-up- it was not until I started modifiying the front end with all the "needed" updates that I started having problems.
-The "sag" I'm measuring is when I tie a zip tie to the fork tube and rest it on the rubber boot of the female sliding unit with the bike on the side stand-I then sit on it and put the bike back on the side stand and measure.
My next plan is taking off the fork brace tomorrow
BTW, if you go to RT's site and calculate the spring weights, mine come out at .96, they say to use the closest number, for me .95's.
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Anyone modify the return side of the Emulator?
Well for those who have thought of this,,, I've restricted the lower valve of each Emulator with three 9/64 pieces of copper, this amount of restriction is a slightly noticable positive result.
Sat. I'll add two more. The addition of these may be too much,,,the three are just fine !!!
Oldspeed
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Srawboss,
The way you are measuring sag is not correct, refer Racetech instructions or the Sportrider link I posted. When the bike is on the sidestand there is weight on the springs, the starting point for measuring sag is with no weight on springs. When putting bike back on side stand there is no gaurantee it returns to exactly the same position. You will need someone to help you.
When you know your actual sag preload and spacer length can be calculated.
Oil level should be measured with emulators fitted but springs not in.
Regards, Russell