Race Tech Gold Valves?
Posted December 08, 2001 - 06:09 AM
There has been some opinions posted here that suggest that the srock KYB pistons are actually superior to the older RT designs, so anyone have any suggested shim stacks (mainly high speed) for the stock forks? The forks are new (4-5 rides) so the mid-valve shouldn't be a problem at this point.
The easiest thing would be for him to simply ship the suspension off to a reputable shop for a revalve, but he really wants to try it himself.
He is a Vet Expert rider. The springs are stock.
Posted December 08, 2001 - 03:33 PM
Posted December 09, 2001 - 05:32 AM
If your friend is doing this himself tell him to check this site out: http://mx393.tripod.com/tech.html and look under the
"Supension section" I have posted a few helpful hints, so that the "average" weekend warrior can install the gold valves w/o all the $60-70 tools from Race Tech!
CLICK HERE to see the setup I am running!
MXTuner who is a suspension guru (who visits this site) recommended this valve stack CL5, CH2 in the forks. He can tell you more if you are interested!
Whenever I get to test out my suspension I will post the results. Because I have gotten lots of emails asking how it is working in comparison to stock? Later,
Posted December 09, 2001 - 06:32 AM
Posted December 09, 2001 - 08:14 AM
Not the case. I bought the front and rear gold valves and also went to 47 fork springs. I had my susp guy valve super soft. triple valved (I think he said) and the 47's would take any huge hit and keep it from bottoming. Works pretty damn good. Although I would like to try a little softer spring in the front just for giggles.
It was like riding a cadilac across the DEZ instead of a tractor!
Posted December 09, 2001 - 08:51 AM
Until I find something better, I'm sticking with recommending Gold Valves.
Posted December 09, 2001 - 01:32 PM
one of the best things i did if not thee best. i've had the rear shock done as well. both to suit 14 stone rider (196lb).
Posted December 10, 2001 - 01:38 PM
When you purchase the Race-Tech Gold Valves, you get a kit. Inside the kit are the valves themselves, and a collection of valve shims.
When you make the modification per instructions, you are removing the factory valve, and modifying the number and types of shims that KYB put in at the factory.
Upon your test ride, you conclude the forks work better. Therefore, you conclude, the Gold Valves are superior. However, was the improvement the change in the valve, or the change in the shims?
The next question would be, what if you modified your forks, changing only the valve stack, therefore keeping the factory valve?
Would the ride be just as good, better, or worse?
More importantly, the question should be, what is wrong with the factory valve that warrants replacing it? And what makes the Race-Tech design better?
What I personally care about is finding out what constitutes the best valve, then what is the right collection of valve shims to go with the valve I have chosen, based on my needs for the type of riding that I am doing.
If I wanted a brain-less fix, I would get the Race-Tech valve kit. It’s nearly full proof. Choosing the type of ride that is needed is as easy as selecting a valve stack number, such as CL2 and CH5. Race-Tech makes their money by making it that easy.
Now back to the question of what is the better valve, Race-Tech or the factory KYB?
The most important consideration in a valve design is consistency of resistance. Meaning, that the valve should be able to smoothly flow oil regardless of how much oil is being forced upon the valve. In other words, there should never be turbulence. The valve has to flow oil without any drag.
In fluid dynamics, this usually means the most direct and smoothest path. Oil that has to flow over and around sharp edges and corners causes the oil to drag in its route. In a poorly designed valve, this essentially means the oil is headed back in the opposite direction by the time it gets to the valve stack.
One way of fixing the drag problem is making the holes of the valves bigger. This is what Race-Tech has done. The other way, is to construct a valve that has less turns and sharp corners. This is what KYB has done.
Either valve with the wrong set of shims will yield a poor ride, and vice versa.
Does the average rider that dares to open his or her forks know what changes to make to the shim stack to better control front wheel movement? Of course not. Neither do most of the people working in the suspension shops that modify your forks. This is why there are Race-Tech valving kits and franchises. Someone comes up with a design that works, and sells that knowledge in a package to others. It’s nothing but smart business.
So back to the subject. In late model forks, KYB, without a doubt, makes a better valve. Race-Tech, without a doubt, has the best do-it-yourself service. Included with that great service, is a well designed new valve.
Posted December 10, 2001 - 05:29 PM
As always, a very interesting reply...
I agree, for a do-it-yourselfer approach to doing suspension, race tech has simplified the process. From a marketing stand point, there goal was this:
Put together a method of revalving the stock suspension on a motorcycle which will deliver an improvement, yet be simplistic enough for the average mechanic to perform.
Again, I believe they succeeded in making an improvement, because a rider can dial his forks closer than the "catch all" stock valving.
Unfortunately, I believe that they have traded performance for simplicity to some extent.
Designing and installing a properly tuned midvalve compression shim stack in the fork can get pretty complicated. When we start getting into pivot points, float settings, and stack build variables, and to figure a way to make this work in conjunction with the base valve in a favorable manner is quite a task.
Even the mechanics of the build process is more complicated than the base valve assembly.
The end result is that the added performance of a properly tuned midvalve is better than a check plate.
If you think about it, midvalve shim stacks (active valving) are the industry standard. This is true in production and in the racing enviroment. One of the few bikes out there that doesnt have a midvalve installed from the factory is the DRZ, it uses a check plate.
Every major motorcycle suspension company, KYB, Showa, WP, Ohlins subscribes to the midvalve philosophy.
Then why we ask, if this is all true, then why can we make the race tech version perform better than stock? Do they know something that the suspension manufacturers dont know?
Motorcycles at an industry level are built and designed with everybody in mind. In other words, they have to build a bike that "everybody" is going to be "ok" with. A tough job , no doubt.
The majority of motocross bikes sold will never see a motocross race. The bike will be sold to all different types of riders, abilities, and riding conditions.
To valve for all of these conditions is difficult, the manufactures must create a suspension setting that they think will make everybody happy. Of course there is a lot of trade-offs with this design, but they really have no chioce.
I beleive that the manufactures do a really good job of valving the motorcycle in respect of how many different levels of riders will ride the bikes.
I now I am getting a little long in the tooth here, but yes, the race tech design will get a rider closer to his abilities/riding conditions than a stock set up.
But, can we get even better results? Absolutely.
You want to try something interesting?
The face shim on a stock KYB is 24mm, the stock face shim on a RT piston is 22mm.
Find a good RT stack build, use the STOCK KYB piston, add 2mm to every shim in the base valve build and toss the midvalve, throw in a check plate and go for a ride. You will end up with what I call the "poor mans" gold valve
The reality of it is that the flow patterns of a RT valve and that of a stock valve are very similar. Why do you think RT went with a 22mm face shim? They didnt want everybody using there stack reccomendations on stock pistons.
The industry standard for a 28mm base valve is a 24mm face shim. The larger the face shim, the more low speed control we can maintain.
The stock ports are not restrictive and do not create drag. Port size has more to do with the "speed" of the fluid traveling through the valve (Bernoulli's Principle).
If you think about it, the most fluid that will flow through a base valve is equal to the area of the piston rod that is in the cartridge at any given moment. We also have to subtract the amount of fluid that has gone through the clicker and also the fluid that goes through the cylinder valve (providing we havent removed it).
The average piston rod is 12mm (WP is 14mm) multiply this times the length of the rod that is in the cartridge and that is how much fluid is being displaced. The max is around 2 or 3 ounces ( I have the exact figures someplace around here) The point is, that there is not that much fluid moving through the base valve, especially not enough to cause any drag or resistence (for practical purposes that is).
Well, thats it for now, I am sure we are into another great TT suspension discussion!!
Take Care, John
Posted December 10, 2001 - 07:12 PM
What difference does a smaller diameter shim make? Since the ports are the same dia. and the oil is pushing at the same point on the shim. The fulcrum to load and shim thickness coeff. are identical. So I guess the only advantage would be more clearance around the shims themselves. To take better advantage of the larger ports?
Oh yeah, the RT valves are better than the stock valves. But the stock ones are the most lethal ammo in the old slingshot yet.PT
Posted December 10, 2001 - 07:33 PM
You have that backwards, as the port size gets smaller , the velocity of the fluid increases, and vice versa.
Shim diameter is everything, think of this in respect to leverage. The further outward away from the center that we move the point at which the oil is exerting pressure on the shim, the more we can control how that shim deflects.
The closer to the center and we are narrowing down the effective range of control.
This is getting pretty involves and we will eloborate more in the morning.
As far as the stock valves being lethal ammo, theres this cat that keeps getting in my trash...hmmmmm.!!
Take Care, John
Posted December 10, 2001 - 08:19 PM
Let's simplify this for a moment shall we, if you guys are gonna argue, you're gonna have to do it in english....sheesh
Any comments on the Enzo (J&M) subtank dumaflechies. If so, what kind of valving works best with this type of set up?
Posted December 11, 2001 - 08:01 AM
I've tried other valving, other pistons, other set ups and still have not found anything to work as well as Gold Valves. Is it possible to get better performance than Gold Valves can deliver? I'm sure it is, but I haven't been able to figure out how with anything I've ever tried. I've consulted other professionals over and over and still haven't come up with anything yet. Am I done trying other things? Nope, not on your life!
Posted December 11, 2001 - 08:47 AM
If I understand everyone, it's really a matter of preference, and the desire to want to work with your options.
Did we miss anything?
Posted December 11, 2001 - 09:49 AM
Posted December 11, 2001 - 10:46 PM
I think the issue of bottoming and inconsistencies in stroke performance are the fault and failures of the mid-valve and cylinder valve. Both of which you modified during the course of installing the Gold Valves.
You essentially changed three factors so be careful which one you draw your conclusion to.
In my little world, the integrity associated with the design of the KYB mid-valve warrants it's removal. And the very same applies to the cylinder valve. When one of the other fails, the fork collapses.
Both can be modified, but I was never able to find a modification that could withstand continual abuse, (trail and woods riders need not worry). So out they went.
And...here we go again.
Posted December 11, 2001 - 03:00 PM
When your forks move they try to force oil through these holes real fast.
If the hole ain't big enough you feel a jolt through the bars. You know that time you hit that sharp bump and it "FELT" like the forks bottomed BUT the wheel wasn't all the way up????
Thats what happens when the hole isn't big enough.
Some people preach "control the oil with hole size" while others worship the "shim stack" ALL BE SILENT BEFORE THE STACK!!
My experience has been use a valve that will flow enough oil for your application then use the shims to give the desired feel.
And remember if you can't get the oil through the hole, you can't control it with the shims.
And John both valves push on the shim at the same distance from center, so the leverage ratio is the same. If it were a wrench and you had one 2" long and one 10" long. If you push on both wrenches at 2" out from the fastener there will be no advantage or disadvantage using the long wrench. Don't make me get out the crayons!PT
Posted December 11, 2001 - 04:20 PM
I can't ride Ga426Owners bike. I start getting way to over-confident and start getting tempted to jump stuff I shouldn't. I don't want my mind to write checks my body can't pay for.
Posted December 11, 2001 - 04:38 PM
When my riding buddy asked me to post this question about the gold valves and recommended valving I had no idea that it would turn into the excellent thread that it has. I love the suspension threads anyway cause I get so much out of them myself. Thanks guys.
Posted December 11, 2001 - 04:46 PM
Thats it , I am breaking out the crayons, construction paper, legos, lincoln logs, and whatever else it takes....!!!LOL!!!
You sound pretty fired up, but I am going to have to take some air outa yer sails....!!
The first commnent you made:
"If the hole ain't big enough you feel a jolt through the bars. You know that time you hit that sharp bump and it "FELT" like the forks bottomed BUT the wheel wasn't all the way up????"
*are you sure the last 4 letters of your last name arent "eade"??!!!! LOL!!
Anyways,...The situation you are referring to would be a " hydraulic lock" (this happens when port size isnt enough to handle the fluid attempting to flow through it). Realistically, , the valve that we use has ports that are smaller than stock and we dont even come close to a hydraulic lock situation. I can build a shim stack that can be very supple and use the entire stroke without "spiking" anywhere.
Also, and this is a big one, do you really think that the engineers at Kayaba would actually build a valve that would cause a hydraulic lock situation because the ports couldnt handle the fluid flow? We are talking about one of the very elementary concerns as far as valve design goes.
And the present KYB piston has been around for years, in Kawasakis and Yamahas, this is not a first year item.
To back this point up, one of the main complaints with a stock KYB fork after a period of time on it is that the fork blows right through the stroke, not spiking. As GA426 was describing how his forks were behaving.
And also....the point you made about the stock KYB piston and the RT piston exerting pressure at the same point on the face shim from center.
If you measure a stock KYB piston, the distance from outside to outside of the port is 23mm, on the RT valve, the distance from outside of each port is 20mm. The stock KYB piston port is 1.5mm further from center than the RT piston.
I dont care what color yer crayons are pardner, thats a whole different leverage ratio.
Take Care and have fun.....John
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