Question about 97 kx forks

Questions and comments about converting to beefier forks..
muddertrucker
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Question about 97 kx forks

Post by muddertrucker »

Just got a set of 97 forks off of ebay for 1$. Of course they're not in the best shape, they have a few scratches and a leaky seal. I've looked over several posts on this site before even deciding to open them up by myself. Now that they are opened up I have a few questions that some of you might able to help me with. I don't have any pics so I'll use the sticky on KYB fork service as a reference.

1. I'm assuming the base valve is the compression assy. (fig 5)

2. Do my 97's have a bladder?

3. I only have 6 big(24) shims in the comp. assy. is this normal or does it mean someone screwed with it before me?

4.Why don't I have any flat spots on the item showed in fig. 6 and 7. If I can't get it off with a wrench how do I?

5. I keep reading LS and HS rebound and I'm assuming that one of those is the mid valve and that they are both positioned in the pushrod assembly in fig. 8 wich I can't get to until I resolve my problem in #4

Thanks for answering.
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Post by scheckaet »

what pics??? no linky
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Post by muddertrucker »

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Post by scheckaet »

1 yes
2 dunno you'll see when you open them (don't think so)
3 dunno
4 weird
5 yes and yes
Not really helpfull sorry.
Are you sure you have no flat spot at all??? Tried to unscrew them by hand?
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Post by muddertrucker »

No flat spots, even tried with vise grips but had to be gentle not to damage it and still no succes.
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Re: Question about 97 kx forks

Post by canyncarvr »

>|<>QBB<
muddertrucker wrote:Just got a set of 97 forks off of ebay for 1$. Of course they're not in the best shape, they have a few scratches and a leaky seal. I've looked over several posts on this site before even deciding to open them up by myself. Now that they are opened up I have a few questions that some of you might able to help me with. I don't have any pics so I'll use the sticky on KYB fork service as a reference.

1. I'm assuming the base valve is the compression assy. (fig 5)

2. Do my 97's have a bladder?

3. I only have 6 big(24) shims in the comp. assy. is this normal or does it mean someone screwed with it before me?

4.Why don't I have any flat spots on the item showed in fig. 6 and 7. If I can't get it off with a wrench how do I?

5. I keep reading LS and HS rebound and I'm assuming that one of those is the mid valve and that they are both positioned in the pushrod assembly in fig. 8 wich I can't get to until I resolve my problem in #4

Thanks for answering.
There is compression valving in the base valve..shims that bend to oil flow during the compresson stroke.

Considering '97 KX250 forks: Bladders were in newer forks, I think. It's real easy to see if yours have or had them if they're apart. It's a balloon thing plainly visible.

Having 'only 6' is not stock valving in any valve I've seen..although that is only a handful..and NOT a '97 valve. Doubt 'only 6' would ever be a planned configuration by anyone that knew what they were doing. In the first place, there are generally more than six 24s..and smaller diameter shims back them up.


Here's a stock compression stack from an '01 KX250 'fer example (from suspensionnetwork):

qty shim
11 24.1
22.1
20.1
18.1
5 16.1
14.15




This is interesting. The question was in regard to '94-98 KX forks and getting the cartridge out.
Terry Hay wrote:
29-10-2005, 10:37 AM
The fork cartridges on the Kawi's varied within that time frame. The 1996 had a 28mm I/D cartridge that was a straight tube. You could access the rebound by disassembling the "bottom out" piston and sliding the damper rod out the bottom of the cartridge. I notice that you have a 97 which may or may not be different. It was around this time (possibly 98) that they had changed to a 32mm I/D cartridge that tapered down to 28mm at the bottom. This made it impossible to remove the damper rod the same way as previous models. For these you had to unscrew the cartridge cap / spring seat from the other end. For this I would suggest that you procure the correct tool that engages the lugs of the cap or at least fashion one from a steel tube. The cap has been loctited in so it will need some persuasion to shift it. I would suggest you lay the cartrige on a flat surface and apply a few sharp taps with a hammer around the threaded area below the cartridge cap. Obviously common sense must prevail when using this method. We are simply trying to loosen the loctite, not alter the shape of the cartridge assembly. Without cartrdge clamps you will need to improvise with your disassembly. Slide a No.2 phillips screw driver through the exhaust holes at the bottom of the cartridge and secure your cap tool in a vise. Engage the cartridge and unscrew. If excessive force is required either apply some heat to the threaded area or try a couple of extra taps.
If you are not completely confident I would suggest you stay away from this area. The rebound valving was pretty close for most riders although the midvalve shims do fatigue after a while. If you are looking for hanlding improvements I would first start by ensuring the spring rates and compression valving were correct for you.
Kaw does mention that cartridges in this timeframe cannot be dissassembled..that they are one piece units. Maybe that has somthing to do with your 'no flats' question.

Some fork disassembly requires a level of fork destruction..drilling rivets, holes and such. I would be very hesitant to be doing that sort of thing experimentally if these forks are something you plan on being useful.

The linked KYB disassembly procedure certainly does not apply to all KYB forks.

Hopefully someone on this site that HAS '97 KX forks that has had the cartridge apart will chime in on the cartridge disassembly.

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Post by saddletramp »

I bought my forks already re-valved from strider 80 a season ago, I would try searching for his post, I know he had photos and Q's while he dis-assembeled them. I have a link to what my base-valve is.
http://www.kdxrider.net/forums/privmsg. ... ad&p=13784
2000 KDX 200 97 KX 125 Front End
1996 CR 250
03 RM 65 2000 YZ 80
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Post by canyncarvr »

That link takes me to my PM page 'fer some reason.

Whether clicked or copied/pasted..the same.

:hmm:

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Post by saddletramp »

Yes, it's a pm regarding how my valving was re-configured. It looks like 6 of the big washers is stock in the base valve. If they were my forks, I would not attempt any drilling to get to the mid-valve. I would make sure the spring rate is correct for my riding style/weight and try them, before I took them in to somebody qualified.
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Post by canyncarvr »

I think the link goes to the PM page of the person signed in.

In any case...it doesn't go to a page that shows how your forks were valved.

How about a copy/paste so we kin see it.

But...maybe I'm simply braindead over the whole matter.
:rolleyes:

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Post by muddertrucker »

Re: Having 'only 6' is not stock valving in any valve I've seen..although that is only a handful..and NOT a '97 valve. Doubt 'only 6' would ever be a planned configuration by anyone that knew what they were doing. In the first place, there are generally more than six 24s..and smaller diameter shims back them up.

I'm not saying I only have 6 shims total but 6 sixe 24 shims plus all the rest.

And thank you very much CC for the text you pasted in tour post it was extrememly helpfull. Actualy its what helped me get the cartrige out. The cartrige was not meant to be taken out on my 97's but that does not mean it's impossible.

The cap mentioned in the text does have to come off but there are 4 little spots that are pressed into the threads to keep it from coming loose plus locktite.

I partialy drilled the 4 spots(but not all the way threw) then set in a vise(gently) heated and twisted with the appropriate wrench(in my case a cresent :? ) Then pulled the cap out but not the hole assy. and drilled out the rest of the spots to allow the big washer thingy and little spring to come out.

Re: If they were my forks, I would not attempt any drilling to get to the mid-valve. I would make sure the spring rate is correct for my riding style/weight and try them, before I took them in to somebody qualified.

Humm, somehow i managed to do the exact opposite of what you suggested and I think nothing is broke. So... does that make me someone qualified?

Besides I only paid 1$ for the foks, If I screw them up atleast I learnt what not to do next time.

And no I do not have any bladders in my forks.

I will post pics of this, and I will probably have a few question on how to screw with the mid valve. :supz:
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Post by saddletramp »

Well nice job, I just meant maybe a buddy who's done it before or something. Anyway good luck.

I saw your post, the valving has been softened a bit from stock, should be good from the woods. The 4X 24mm was 6X2 4mm stock.
mod 1997 KX125
Base valve:
nut
cup washer
spring
25mm washer
collar
piston
4X 24mm
2x 22
20
18
14
16
11
2x 18 thick




cartridge valving:
nut
washer
5x 11
14
17
20
15
23
3x 27
piston
4x 27
26
24
22
20
18
16
2 x 14
thick 25
collar
cup
2000 KDX 200 97 KX 125 Front End
1996 CR 250
03 RM 65 2000 YZ 80
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Post by muddertrucker »

How do you get the number for each shim?

Witch part of the base valve is it that people modify?
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Post by muddertrucker »

Ok, figured out the shim number for myself.

There are 2 difference with my valving and yours

I only have 4x11

in between the thick 25 and the collar I have a spring.

Since the day i've started to read up on all the different forums I was always afraid to fiddle with suspension. Now that i have done the shim stack mod on my conventionals, rebuilt my shock and torn apart my kx foks, I realize that I may have conquered my fear. :supz:
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Post by canyncarvr »

Well, I guess '..have only..' is not the same as '..only have...' 'eh?

damn English anyway.....

Besides, being now 'someone qualified' and having 'conquered' your fear..you're well on your way to opening up your own s'penshun shop!!

I notice saddletramp says 'KX125'..but you didn't. Are your '97s off a 125 or a 250? They aren't setup the same. 4x24s seems light for a KX250. OEM setup I mean. Probably fine for the woods. It must be fine, 'cuz I'm running 4x24s. :wink:

Another matter of note that I don't see noted. Some stacks are comprised of .15mm shims...some of .10. Mine are .15mm. I'd prefer the other, just haven't gotten around to ordering a bagful-o-shims. If you're going to compare stacks..make sure you're comparing apples to apples..and that includes how thick the apples are.

Re: 'How do you get the number for each shim?'

For a reader that maybe hasn't figured it out for themselfs, there are three factors used for shims: Inside hole diameter, outside diameter, thickness. The outside diameter is sometimes only what's listed, as in the columns above. A 2x24 would indicate quantity two of a 24mm outside diameter shim. If those numbers are followed by a '10', they are .10mm thick, if by a '15', they are .15mm thick.

...which btw corresponds to .004" and .006 respectively.

Re: 'Witch part of the base valve is it that people modify?'

Evil retorts aside (Witches and Warlocks, OH MY!!), I assume you mean OTHER than the shim stack? Usually the piston. Aftermarket pistons flow a LOT more oil than OEM pistons in most cases. Some of that is the size of the ports, some of that the design of them. I suppose a 'real tuner' would modify the LSC in the base valve. Using a Gold Valve replacement setup as a guide, the major parts of those are the piston and shims.

RE: 'The cap mentioned in the text does have to come off but there are 4 little spots that are pressed into the threads to keep it from coming loose '

Crap. I knew that...just didn't recall it, which is why I generalized about drilling and such.

Good job on the whole deal!!! You are absolutely correct about the 'conquer' part. Now that you know how they come apart...you can tune them to suit you, and that means your rides will be a lot more fun!!

Are you replacing seals and bushings?

MAKE SURE the tubes are straight before you put money into the seal/bushing parts! There's likely some reason they sold for a buck.

If they leak like a sieve but have all the threads in the right holes AND are straight..that's an excellent find!

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Post by muddertrucker »

Re:Besides, being now 'someone qualified' and having 'conquered' your fear..you're well on your way to opening up your own s'penshun shop!!

Not quite. I`d wait to see if I can put it back together first :oops:

Re:I notice saddletramp says 'KX125'..but you didn't. Are your '97s off a 125 or a 250? They aren't setup the same. 4x24s seems light for a KX250. OEM setup I mean. Probably fine for the woods. It must be fine, 'cuz I'm running 4x24s.

They are from a 250. i thought the only difference was spring rate. I'm at 185 without gear so I figure the springs are ok.

Re:Evil retorts aside (Witches and Warlocks, OH MY!!), I assume you mean OTHER than the shim stack? Usually the piston. Aftermarket pistons flow a LOT more oil than OEM pistons in most cases. Some of that is the size of the ports, some of that the design of them. I suppose a 'real tuner' would modify the LSC in the base valve. Using a Gold Valve replacement setup as a guide, the major parts of those are the piston and shims.

I think I read somewhere that you can turn the mid valve into a check valve by flipping one of the parts and putting it in backwards, but I just can't find the thread anymore.

Re:Are you replacing seals and bushings?

MAKE SURE the tubes are straight before you put money into the seal/bushing parts! There's likely some reason they sold for a buck.

If they leak like a sieve but have all the threads in the right holes AND are straight..that's an excellent find!

Yes i did plan on changing the seal and bushings. So far using a calibrated straight edge the inner tube on the fok that is apart is staight. The outter tube seems to be a little trickier to mesure seeing as the outside is tappered and the inside is to small to fit my straight edge.

Once again thank-you all for your help.
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Post by canyncarvr »

RE: 'I think I read somewhere that you can turn the mid valve into a check valve by flipping one of the parts and putting it in backwards, but I just can't find the thread anymore.'

I don't know how well it works, but, I've read similar input. I've also read this: The midvalve being such an important part of the suspension action, not knowing how to tune it and therefore removing it is a fools errand.

THAT said I'm sure by folks that figger they DO know how to tune the midvalve. The 'spike' complaint that seems popular from those with poorly setup midvalves can be resolved with proper tuning it seems.

Just 'cuz it's harder to get to and more of a hassle doesn't mean you resolve those issues by defeating the valve's function.

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Post by Jeb »

For the record, when I installed the Race Tech Gold Valves in my KYB forks (albeit from a '98 YZ yet similar in technology) the Race Tech installation instructions strongly recommended replacement of the midvalve assy with a checkvalve and provided the pieces to do so. It did go beyond just flipping something in the midvalve section, though. Besides just the checkvalve portion (washer + spring I believe) there's actually a sort of a labrynth seal at the top of the compression cylinder (immediately under the cap) that is "defeated" with a sealing mechanism. The two changes work together.

I really found very little on which to rely to help me with what type of changes to make to the midvalve. I found, and you may too if you pursue this, that feeback in this regard is thin (my feeling is that most just don't know and send 'em off to a tuner). Further, it's not exactly changed quickly (at least for me and my limited skills).

So rather than "fool" with the midvalve section I went with RaceTech's recommendation. I personally was very pleased with the results, very plush yet reasonably stout, and rebound/compression changes are now actually quite noticeable, i.e. it made the bike tuneable.

I'm was under the impression, by the way, that one can buy the conversion kit, perhaps from Racetech.

Having stated all of this, keep in mind that:
1) I'm no x-pert at this stuff, it's pretty much been trial and error with some help from my pals here on the site.
2) My belief that my current arrangement being adequate is based on my current skills and I am at most a novice.
3) There's folks out there that of the opinion that it's a downright bad idea to NOT use and tune the midvalve. Jeremy Wilkins of MX-Tech is one such opinion. He's probably right for the likes of Charlie Mullins and David Knight; I'm not so sure about that for a pea-dinkle like myself. 'Problem is, I've not heard WHY a correctly tuned midvalve is superior to a checkvalve, only that people like Jeremy say so.
4) I can't stand the thought of foregoing superior performance and, if I keep the 220, I'll probably send my forks off this winter.

Many send their forks/shocks off to the more "commercialized" outfits (MX-Tech, RG3, Moto-pro, etc) and that's OK, but ask people at the track and the trails and sometimes you'll find some smaller shops that do a terrific job. I'm considering sending mine to Bruces Suspension in North Carolina because the guys I've talked to love his work (and supporting the little guys, when possible, is my preferred way).
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Post by canyncarvr »

Yep. All that.

..and likewise.

I'm no x-spurt, don't claim to be and likewise use trial and error when fussing with lots of stuff. What I like someone else might think is so incredibly bad as to be undrideable. Sometimes ignorance is bliss!

It was Jeremy Wilkey I had in mind when I espoused upon the midvalve issue (defeat or shim it). That's something that tinges my particular beliefs about the whole thing...'cuz Wilkey has worked on summa my 'stuff', and I've very much liked the result. While it doesn't follow at all, logically, I do then put more weight to what he says about other things.

There are plenty of areas in dirtbiking that are wholly (and with no other support) 'IMO'. Hopefully that opinion has been attained through at least SOME looking into the subject and maybe a bit of experimentation.

I've supported local guys when I can. One shop did excellent work on my shock..his legwork wasn't as good as Wilkey's...so I changed it back to Wilkey's setup after a few rides.

Yeah..there's a point..and yeah...I take forever getting there.

In regard to suspension (and other places...but suspension is the subject), don't be afeered of some experimentation on your own. You may well get it all sorted out to suit you. At the least, hopefully, a better understanding of 'the way things are'.

This has been an excellent thread in a number of regards...excellent input from those that actually know something (saddletramp 'fer example) and questions from someone willing to listen, do stuff, and tackle what WAS unknown at the time (mudder).

Questions asked..answered...new things discovered....

GREAT!

Oh...I think this got lost someplace along the way. The link posted to the stack info? That link indeed takes 'you' to 'your' PM page, not to A PM page (somebody other than the person who's logged on to the site). So...don't do that if you want anyone to actually FIND something.

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Post by saddletramp »

I believe my 125 springs are .38 progressive at least that was oem. They are WAY softer that the forks on my 96 cr250 KYB's.
2000 KDX 200 97 KX 125 Front End
1996 CR 250
03 RM 65 2000 YZ 80
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