Ok Suspension Gods, Weigh in on This.....
Posted January 02, 2002 - 04:51 PM
"The factories switched to mid stage valve stacks in the mid 90's because it allows more control over the oil flow. The lower adjuster actually has about 1/4 the oil flow that that the mid speed valve passes. Using the mid speed as a valve stack increases the possibilities for oil control over using only the lower stack. I would only remove the mid-valve if you were a 60 year old trail rider."
What do you guys think about that concept?
p.s. I will let the suspension shop I heard from remain anonymous.
Posted January 02, 2002 - 07:28 PM
The shop that you are talking about is most likely MX Tech...they are the shop I would have taken my suspension to if I didnt want to do it myself (because all the reviews I have heard are all positive...and from what I have gathered on DRN is Jeremy cares about "the customers")! The main reason I did the Race Tech route is user friendliness...and it turned out with awesome results (thanks MX Tuner)!! Any suspension that is valved/sprung more towards your skill/weight will be better than stock...the question is, "who you gonna pick?" and "do you want to do it yourself w/no previous experience?" Good Luck,
Posted January 03, 2002 - 05:38 AM
One problem with the midvalve is the fact it can change as the shims get weaker. This means your nicely revalved forks suddenly got too soft. Now you have to send them back to get them fixed. This repair is not a free service, either. By disabling them, this varialbe is eliminated.
Posted January 03, 2002 - 06:22 AM
Posted January 03, 2002 - 08:31 AM
This guys needs to understand that we agree that removing the mid-valve would make the suspension too soft. Just like it gets when the mid-valve wears out.
The fix is to remove it with a modification to the cylinder valve.
However, even though I don't run one myself, I still think the best approach is to probably re-design the mid-valve so to allow a variable of stacks without the issue of failure. That way you can benefit from the initial purpose of the valve.
Perhaps you can send this guy the link to this site. Allow him to defend his ways.
Posted January 03, 2002 - 12:00 PM
When you remove the midvalve you are greatly limiting the "range of adjustability".
It is pretty basic, we are trading performance for simplicity.
Think about the variables when "tuning" the compression circuit on a late model YZ fork;
1. Base Valve Piston Port Design
2. Base Valve shimstack
3. Base valve bleed circuit
4. Midvalve Compression shimstack
5. Midvalve Compression shim stack "float"
6. Midvalve bleed circuit
7. Cylinder valve
8. Oil weight
9. Oil height
Each one of these "variables" has a certain amount of performance and adjustability.
Now if we remove any one of the "variables" we loose a certain "range of adjustability" and performance.
Without a doubt the job of tuning gets easier if we remove a variable, its a trade-off.
Out of all the variables, the midvalve is what usually frustrates most tuners. Combining the right amount of float with a good shim stack build takes time and testing. If we build the shim stack too "soft", it ends up warping and loosing the ability to dampen. If we build it too stiff, it acts like a check plate.
The testing is time consuming, because even the smallest of change in the midvalve requires a complete teardown.
Think about this, how about we design a midvalve shim stack for a gold valve? Can it be done and make it better? I bet you with some time and testing, we could it get it to work real good. How much better, only one way to find out.
A midvalve that is well supported will last...
Well, you knew I could'nt keep quiet on this subject
Take Care, John
Posted January 03, 2002 - 12:54 PM
Cool post dude. I agree.
There are some on this board that are using modified mid-valves that just may be working. I tried some stuff last summer that made things better, but never proved to be as stable as removing it.
I would agree I lost control over mid-speed, but I gain in other areas. Those gains are substaintial, which supports the RT approach.
Can we develop a mid-valve assembly that works? I think so.
What I would really like to do is build a bench tester where one could profile and plot inputs and responses. Get scientific...ya know.
Be real cool if you lab this stuff to near perfection. Then ride away smoothly.
Posted January 03, 2002 - 05:12 PM
Good point about building a stack to work with the GV's, as long as it wouldn't wear or weaken with age. I see your point about removing variables limits adjustability but the fact of the matter is as long as you get the results you desire, why hassle with them?
I like DaveJ's approach about getting dwonright scientific with monitoring changes scientifically but the $64 question is........ how?
Posted January 03, 2002 - 06:10 PM
Well, its more like a 30 grand (minimum) answer.. A shock dyno that can run forks.
This is the next step in testing. I think with the right set up, alot of the initial design work can be completed on a dynonometer.
Actually, I think the best would be a mobile unit, that can be transported to the race track. Then we would be able to do real world testing in comparison with the dyno readings.
Well, thats our goal anyways, I'll keep you posted...
Take Care, John
Posted January 03, 2002 - 09:08 PM
YZ450FX OR YZ450F by MESSMAKER
Snake pit oct 30th by The Anvil