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Gold Valve and Mid-valve

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cesper, as long as you offered, I have questions.  That drawing in the link, I don't see that the thing labeled "clamp"  does much of anything except maybe a spacer to set the stack height.  As for the "float" dimension, the drawing just isn't clicking with me.  The dimension on the closed float diagram from the cup washer to the heavy (black) washer is the same dimension as the open float diagram from the piston face to the first shim.- assuming the shims don't distort, which they may do.  As for MY float dimension, I can push the shim stack against the spring tension until the shims hit the cup washer and I get a hair under TWO mm. between the piston face and the shim. But that would be the same measurement as just measuring the gap between the cup washer and the other large shim when NOT compressing the spring.  I haven't measured any shims yet.  I want to figure out what I'm looking at first.

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Sorry, ignore that CLAMP shim in the diagram. Also, when you are measuring float, you are probably flexing the shims or not lifting up the stack evenly because 2mm is a ton.

Read this-

http://www.thumpertalk.com/topic/1053530-measuring-mid-valve-float/

Also, keep in mind that float is the amount the stack is allowed to move by the spring WITHOUT the shims flexing. Behind the shims there should be some kind of spacers, washers, or shims that limit the stack from hitting the cup washer. When the float is at max and the shims start to flex from the pressure, then they will stop against the cup washer.

Edited by cesper

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2001 YZ's have a cartridge valve that allows fluid that would normally be passed through the base valve to bypass out the top.. Because of this feature the base valving is 3x harder than it would be if this cartridge did not have one..

The Cartridge valve shims are notoriously unreliable, causing the fork to dive , lack rebound control and be very harsh..

Race tech sold a cartridge valve removal kit which contained a seal that sat underneath the cartridge bush head where the damper rod enters the cartridge., it added stiction and was a pain to fit!!

Terry Hay designed a complete seal head that eliminated the OEM part and reduced friction..

With adjusted valving this completely transformed the fork ...

Email shocktreatment in Aust ,

Im sure Terry would be glad to help!!

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Sorry, ignore that CLAMP shim in the diagram. Also, when you are measuring float, you are probably flexing the shims or not lifting up the stack evenly because 2mm is a ton.

Read this-

http://www.thumpertalk.com/topic/1053530-measuring-mid-valve-float/

Also, keep in mind that float is the amount the stack is allowed to move by the spring WITHOUT the shims flexing. Behind the shims there should be some kind of spacers, washers, or shims that limit the stack from hitting the cup washer. When the float is at max and the shims start to flex from the pressure, then they will stop against the cup washer.

When I measured, I was very careful to not flex the shims and measured it several times.  I wish my camera did better close-ups, something is wrong with the macro or I'd attach a pix.  Yes, 2 mm. doesn't seem right considering they were super harsh.  I think my best option is, instead of experimenting with mid-valve AND base valve shimming, to just give it to my suspension guy.  He's confident he can greatly improve them and has a good reputation in my area. 

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After reading KBRPKENNY's post, this fork seems to have some particulars. I believe you on the float measurement, possibly you are blowing through all the travel, using too much beginning travel, who knows. I personally am in the process of trying to dial my shock in for my location change(from east coast woods to desert) and have to sit down and think "am I bottoming or not using enough travel?" sometimes. That's why suspension is so awesome and so confusing, a lot of it is subject to rider feedback.

My friend who literally just started riding on a YZ125 2002 says his bike rides awesome. I get on it and notice it way too stiff fork springs and alignment so crooked it's binding, way too much shock sag (even for my 30lbs less than him) and the previous owner?!?! When we picked up the bike.....shock, TOTALLY BLOWN, oil is all over the back of the bike and a short test ride by my reveals you can basically do a stoppie without using the brake! I rebuilt his shock and it had MAYBE a shot glass worth of oil in it. Luckily, no permanent damage inside....

But anyways, my recommendation to you is to have a tuner, whether pro or garage with actual experience on this exact model fork to help you out and get at least a good baseline. If you wait, some will probably chime in here real soon. If you can't wait, send them off or get the gold valve kit. You've gone this far with the work, so you can probably install them yourself. And if you get hung up, TT is the place for help! Helped me SOOOO many times, and I transferred that to my friends' bikes, etc....

I could try to explain the mid valve function all day on here, but in reality I have no real world experience on this model. I might soon though if my buddy's YZ has this fork.

I would also recommend highly to read the Racetech Suspension Bible, very valuable! It won't give you the slightest info on what size shims to use, but it covers a good range of theories as a foundation. Then when someone says "use this stack" you can start to understand why. Another thing it helped me with is when riding my bike i can think about what areas to address. Usually, lol..

But I'm by no means an expert, seriously. Don't get me wrong.

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I can tell one thing for sure, I WASN'T hitting bottom.  The FIRST time I rode the bike, I didn't think it was using much travel in the forks and seemed to sit high (THAT I still don't understand since valving should have no effect when you're not moving!) so one day I had a practice track all to myself, I put a tie wrap around the lower fork leg to see how much travel I was using. I was barely using half of the travel, in spite of screwing up a couple of jumps and landing HARD.  BTW- I repeated this test later with shuffled shims on the base valves and minimum oil height.  I maybe gained an inch of travel.  It's weird because I'm sure the springs are stock, the PO was just a little guy, and I'm WAY heavier than him.

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One point about my experience with my YZ, combine forks that seem to always sit too high, a rear shock that sits too low because of a too soft spring(replaced now) and you have a bike that turns REAL LOUSY.

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The older forks with the huge cartridges did have lots of float

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One point about my experience with my YZ, combine forks that seem to always sit too high, a rear shock that sits too low because of a too soft spring(replaced now) and you have a bike that turns REAL LOUSY.

Yeah, you're not kidding. Rode my friend's YZ125 today a little bit and it was definitely different from my KX. I rebuilt the shock and it's definitely been revalved, but no clue on the fork. First thing I expected was for the forks to be harsh, but they weren't bad. Rode very high in the stroke, but not even close to as harsh as my KX forks were in stock form. And the rear rode very low, but the damping was decent and kind of masked the weird front to rear imbalance. Racetech's site says to drop 2-3 rates on the front springs and increase 2-3 on the shock, go figure!

And man, the YZ power delivery is so much smoother than my KX, it could pass for a 200cc four stroke if I was deaf, lol.

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One option would be to get a comparable set of KYB's but from a Honda.  You can swap the cartidges to get rid of that CV valve the YZ's have.

 

I've seen sets of 2000-2001 Honda CR125 forks from  $100-130 to your door.  I just picked up a second set from an 04 that I made woods forks out of and I am very happy.

 

 

Another option would be get a set of newer WR forks but they are much more expensive.

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Kbrkenny nailed it. Your fork has a cylinder valve at the top of the cartridge. This will really effect fork function as excess oil is allowed to bleed off from the cartridge. All your valving is heavier than a standard fork in order to compensate. The valve function can be disabled if you have the capacity to access it as well as a lathe.

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The mid-valves are already out and apart.  I think I'll just take it to a suspension guy.  I don't have time to experiment with different valving schemes and repeated dis-assembly.  Since it's the off season, now is the time to do it for me.  Unless you like riding in snow and ice, (I don't), Minnesota's riding season is kind of short and I've wasted enough time the last couple of years doing R & D on a 15 year old Yamaha. I want to RIDE it.

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If you are going to take it to a suspension guy then get him to negate the cylinder valve for you. If  he doesn't know what you are talking about....I would look for another guy.

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If you are going to take it to a suspension guy then get him to negate the cylinder valve for you. If  he doesn't know what you are talking about....I would look for another guy.

Yeah, we've already chatted about it and he knows exactly what I'm talking about and what result I want.  We'll also discuss  what happens if I don't like it.

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I haven't taken the mid-valve to the suspension guy yet, (had the flu for a week) but I was looking at my base valve today.  In appearance, the gold valve that everyone's seen apparently has a much larger capacity for flow thru it with the large ports.  So, if that's the only difference, I don't see why an OEM base valve could be drilled to give it more flow capability too.  If that IS the difference, I sure can see how the OEM is limited in flow. In appearance, the OEM has MUCH smaller area for flow.  What I'm thinking is, it possible to re-shim the mid-valve, then make the OEM base valve actually work like it's supposed to with the clicker really making a noticeable difference ? 

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