i installed race tech gold valves in my 96 cr 250.FOR THE FORKS it tells me to convert my midvalve to a chech valve. what i was woundering is when a fork compresses and the rebound rod is forcing oil down threw the fork cartridge you would think that most of the oil would escape out threw the midvalve shim stack. witch would mean that the shim stack on the compression stack wouldnt effect the compression VERRY MUCH. CAN ANYONE EXPLAIN WHY THE COMPRESSION SHIM STACK EFFECTS THE COMPRESSION MORE THAN THE MIDVALVE.
? Midvalve Vrs Compression Shim Stack
- Thread starter cr lover
- Start date
marcusgunby
LIFETIME SPONSOR
- Jan 9, 2000
- 6,450
- 2
You can make the midvalve very active or hardly at all-thats the beauty of the system-tunability.A check plate has no adjustment.
cr lover, I think, and I may stand to be corrected, that you are a little confused about what is happening in there.
While it is true that "most of the oil would escape out threw the midvalve shim stack", this will always be true, but this is not what activates the base valve. The oil the flows throught the base valve is the oil displaced by the damper rod, not by the "plunger" effect of the midvalve. This is a common misconception. Oil must flow throught the midvalve or you would create a vacuum on the downstream side. This being said, it is that there is not a tremendous volume of fluid passing through the basevalve. You can quickly figure out the exact volume by calculating the cross sectional area of the rod (I think yours is 12mm diameter) and multiplying by the compressed distance of the fork.
Did that make any sense?....I am a bit sleep deprived, so bare with me :D
While it is true that "most of the oil would escape out threw the midvalve shim stack", this will always be true, but this is not what activates the base valve. The oil the flows throught the base valve is the oil displaced by the damper rod, not by the "plunger" effect of the midvalve. This is a common misconception. Oil must flow throught the midvalve or you would create a vacuum on the downstream side. This being said, it is that there is not a tremendous volume of fluid passing through the basevalve. You can quickly figure out the exact volume by calculating the cross sectional area of the rod (I think yours is 12mm diameter) and multiplying by the compressed distance of the fork.
Did that make any sense?....I am a bit sleep deprived, so bare with me :D
Jeremy Wilkey
Owner, MX-Tech
- Jan 28, 2000
- 1,453
- 0
JTT,
Bravo with Marcus and you I could take a vaction... :)
Anyway I think that mis conception is defienlty part of the marketing stratigy..
Now the real reason for midvlaves..
If we attempt to build all of the damping from the base-valve we have to control a wide speed range centered towards the mid-speed for bottoming resisistance. If we include no midvalve we will be reling on a relatively stiff stack. This stack as speed increases will allso produce an excess of highspeed compression which results in harshness.. Now if we allso include a midvalve we can set it up to "float on the lowspeed" meaning it does not contribute to the overall damping coeficent at that speed range, and as the fork picks up speed the valve starts to contribute resiatnce.. Given that it is contrubuting the base-valve can be reduced in overall coeifecent and that allows for less overall high speed.. We tune with more than one circut we can overlay the parts about each of them that serve our purposes.. Maximizing the given flow charercteritics and miziming the negatives..
Br,
Jer
Bravo with Marcus and you I could take a vaction... :)
Anyway I think that mis conception is defienlty part of the marketing stratigy..
Now the real reason for midvlaves..
If we attempt to build all of the damping from the base-valve we have to control a wide speed range centered towards the mid-speed for bottoming resisistance. If we include no midvalve we will be reling on a relatively stiff stack. This stack as speed increases will allso produce an excess of highspeed compression which results in harshness.. Now if we allso include a midvalve we can set it up to "float on the lowspeed" meaning it does not contribute to the overall damping coeficent at that speed range, and as the fork picks up speed the valve starts to contribute resiatnce.. Given that it is contrubuting the base-valve can be reduced in overall coeifecent and that allows for less overall high speed.. We tune with more than one circut we can overlay the parts about each of them that serve our purposes.. Maximizing the given flow charercteritics and miziming the negatives..
Br,
Jer
spacerider
Member
- Jun 24, 2002
- 11
- 0
Ok,what is a good stack for the midvalve to start with.
cr, first I don't think you will get a reponse from Jer regarding prices, he like to keep business off this board...call him at the shop, or e-mail him directly.
As for the midvalve setup...if only it was that easy :( What I have found through testing is that there is not "magic setting" and that the setting that works for you may be different for someone else and all this coupled with the working relationship between midvalve and basevalve...they have to work together. It's a very complicated web and more than can be typed here....and more than I actually understand. :D
As for the midvalve setup...if only it was that easy :( What I have found through testing is that there is not "magic setting" and that the setting that works for you may be different for someone else and all this coupled with the working relationship between midvalve and basevalve...they have to work together. It's a very complicated web and more than can be typed here....and more than I actually understand. :D
- Thread starter
- #8
now what
ok now that i know that it is important to have a midvalve, can anyone give me an idea what to do with the midvalve and the basevalve compression stack?
do i put the midvalve back in along with the stock shim stack? And i would think that the spring that is on the midvalve shim stack would effect things also.
And now that i no that i wasted $135 for race tech gold valves for the forks. what is wrong with the other $135 that i spent for the race tech gold valves in the shock?
NEXT TIME I AM GOING WITH MX TECH!
ok now that i know that it is important to have a midvalve, can anyone give me an idea what to do with the midvalve and the basevalve compression stack?
do i put the midvalve back in along with the stock shim stack? And i would think that the spring that is on the midvalve shim stack would effect things also.
And now that i no that i wasted $135 for race tech gold valves for the forks. what is wrong with the other $135 that i spent for the race tech gold valves in the shock?
NEXT TIME I AM GOING WITH MX TECH!
Last edited:
Whow there cr, the money spent on Gold valves is not wasted. Although it is true that they disable the midvalve, they do give you broad tunability and variety of parts to do it yourself. My suggestion would be to use them to their fullest. Try a multitude of valving specs that they offer, take the time to see what is going on and why. The learning experience is definitely worth the price of admission. If you "just send them away" you are not gaining the experience and education of doing it yourself. All this assuming you actually care :) ...as many simply want them to work, and don't care how or why. I personally,am just not that type (sadly sometimes) :think:
marcusgunby
LIFETIME SPONSOR
- Jan 9, 2000
- 6,450
- 2
I adgree with JTT completely, cr lover you can learn so much doing it yourself it would be more of a waste not to try.Almost any piston set up can work really well with carefull tuning.I know someone who has a 02 cr125 fork with gold valves and no midvalve and loves the performance.I havnt rode a bike with gold valves but many riders have and liked them.
- Thread starter
- #11
sorry everone i just get a little negative at times. i will try and figure out something. right now i am having problems with my hi speed valving. i adjusted the forks to where they just bottom out on the bigger hits,but on the little stuff the bars are coming out of my hands.thanx again to all that helped.i will come back for anymore ideas.
- Thread starter
- #13
96 cr with kyb forks.type 2 gold valves because i am 230lbs without gear. i am running dual stage because i like soft forks but i hate to bottom out hard. also as you know dual stage is better for novice rider like me.high speed is ch6 and low speed is cl4 i think,with 90mm of oil.rebound is 15 out and compression is 12 out.i also have the correct fork spring for my weight.
Last edited:
steve125
LIFETIME SPONSOR
- Oct 19, 2000
- 1,252
- 0
Did you ever convert your mid valve to a check plate? When i valved my forks i first rode a few times with only the base valve done, then it was later on that i converted the mid valve. The difference was noticeable but not a big deal. Your hs compression at ch6 may be a little stiff and your ls at cl4 sounds very soft. I would try ch4 and cl6, on the chart each step is a 10% increase or decrease in damping depending on what direction you go. If you have an air gun you can just turn the bike upside down and zip out the base valves for a quick revalve. Remember to clamp off your fuel cap hose and trans vent. I'm running a cl7 ch3 and it's very plush with a good bottoming resistance.
Last edited:
CR Lover,
I checked an old set of gold valve instructions I had laying around and did a manual calculation for a 230lb., novice ("C" level), MX rider and I got Cl8, Ch4. If you like woods riding and not MX try Cl6, Ch3. Those should be a reasonable starting point and as Steve said, you can just flip the forks over and extract the base valve to do the mods. Good Luck!
I checked an old set of gold valve instructions I had laying around and did a manual calculation for a 230lb., novice ("C" level), MX rider and I got Cl8, Ch4. If you like woods riding and not MX try Cl6, Ch3. Those should be a reasonable starting point and as Steve said, you can just flip the forks over and extract the base valve to do the mods. Good Luck!
cr lover,
No problem! Keep in touch with the results. There are a number of us around here that will be glad to help you get the bike dialed in.
On a side note, I forgot to mention that that the settings I gave you were for "soft" or "plush" as you mentioned that in a previous post. So the setup should read 230lb, MX, "C" level, soft setting: Cl8, Ch4 and,
230lb, Enduro/trail, "C" level, soft settings Cl6, Ch3.
Good luck.....with the new addition and the bike!!
No problem! Keep in touch with the results. There are a number of us around here that will be glad to help you get the bike dialed in.
On a side note, I forgot to mention that that the settings I gave you were for "soft" or "plush" as you mentioned that in a previous post. So the setup should read 230lb, MX, "C" level, soft setting: Cl8, Ch4 and,
230lb, Enduro/trail, "C" level, soft settings Cl6, Ch3.
Good luck.....with the new addition and the bike!!
