02 kx forks

Questions and comments about converting to beefier forks..
muddertrucker
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Post by muddertrucker »

Alright, I started tearing into my 02 forks this weekend. To spare anyone here from making the same mistake I did (wich I probably wouldn't have had I read a little more on the subject) I took some pictures to show the right way to remove the bladder.

This is the collar at the bottom of the bladder.
Image

Push it upwards to reveal the circlip wich keeps from going downwards, remove cirlip.

Image

Pull collar off and then remove 3 springs at top of bladder (seen in previous posts), now you can pull bladder off.

Doing this requires several precision tools such as a thumb and index finger and a small flat tipped screwdriver. These tools require proper calibration using 2 or 3 beers.

I however had ran out the night before and decided to cut the bladder off using a utility knife (well actualy only a blade cause I couldn't find the handle)

I did not proceed to modify the restrictive barrier (washer) but I did pull apart the mid valve this is what it looks like

Image

These are the numbers stating from th e bottom up

nut
washer
1X11
1X14
1X16
1X17
1X20
1X12
2X23

PISTON

3X25
1X22
2X20
1X17
1X15
1X12 (WASHER)
2X15
1X17
1X20
1X22
3X23
1X20

SPACER
ORING
CUP
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canyncarvr
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Post by canyncarvr »

I'm missing the mistake part.........

I was ready to hear about you chiseling the band off with a...well...a chisel! What else do you chisel with?

Is it the 'proper calibration' you were missing? :wink:

You have the 'daisy petal' in mind to modify that RB?

What are your questions (or do you have any) about the stack? Notice you have no bleed (smaller shim) before the 3x25s.

...and 3x25s seems to be pretty much on the stiff (non-plush?) side to me.

I'm currently running a 20mm bleed and 2x25s. Just dropping one of the face shims (had 3) made a considerable hi-speed difference on my forks. They used to jar pretty hard, say, coming down from up in the air. Much nicer, now.

Anyway...to each his own.

Tune 'em up!! :wink:

Oh...wait...make sure you have the proper fortification first!.

(that's 'proper calibration' to you!)

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muddertrucker
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Post by muddertrucker »

The mistake was to take a knife to the bladders making them completely uselless, no wait they were already useless make that unusable.

CC you're jumping the gun, the whole daisy petal thing was supposed to be for tomorow. Actualy I was thinking of making wholes that would match the ones a the top of the cartridge where the RB sits.

Image

The tricky part will be to make sure the holes line up. Ill probably en up just make daisy petals.


The stack is actualy the stock one, I may actualy have a bleeder when I put all the shims back together I noticed some had stuck together but that was after I had written every thing down and I knew I was gonna take em apart again sometime. Could I take one of the two 20's and use it as a bleeder?
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Post by muddertrucker »

Mx tech says for my weight I need .43kg springs and stock is .40 kg. My 97's have .43kg springs in them but they are 3 mm narrower and will not fit over the spring guide on 02's. I'm wondering if there is any good reason not to put the 97 spring and guide in the 02 forks. they are a little shorter like 1/8 inch.

The top one is the 02

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Post by Indawoods »

If the guides fit... try it!
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Post by canyncarvr »

MX-Tech...or RaceTech?


Re: 'Could I take one of the two 20's and use it as a bleeder?'

Yes we can!!


I believe a major problem is trying to 'fix' a suspension that has the wrong spring to start with. Cranking up clickers and valving to compensate for a too weak spring is not what's going to lead to anything 'plush'.

That said, .43's are pretty stout (Wookies need not reply). Expert site recs have always seemed on the high side of spring rate to me. I've tried their recommendation..and not cared for it.

All of which is anecdotal, based on what I like..and therefore meaningless to anyone else.

There is more to the correct diameter of the spring than the guide that fits in it. What about the other end? That and 3mm change in preload is significant. I preferred 5mm over 8mm in the OEM RSU forks. I was surprised to find that it even mattered.

The idea of matching holes is good. All you need to wonder about is how to keep it from moving, 'eh? Meaning...it will move. Then what?

Gotta watch that sticking together part. That's what shims do best when you're taking a valve apart. I've had more than a couple stick together even when paying particular attention that it NOT happen.


Ski knows about that. :wink:

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muddertrucker
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Post by muddertrucker »

I took the mid valve apart again today and was gonna take one 0f the 20's and place it in between the piston and the (now) 2 25's. When I first took the MV apart I had noticed some strange marks on one of the shims. This time around I payd more attention to the makings, and they just so happen to be on one of the 2 20's and they look exactly like maks that would be left on a shim if it were the first in line after the piston. So now I'm thinking these forks originaly did have a bleeder shim and someone wether it be intentionaly or not moved it around. I know it wasn't me.

I'm still not sure what to do about the springs. Wich ever guide I choose it will still need to be modified to fit.

MX tech says 97 kx 250 has .43 springs 02 kx 125 has .40 springs and 02 kx 250 has .40 springs, and that I need .43

Race tech says 97 kx 250 is .40 springs and I need .43 02 kx 125 .41 spring and would need .42

According to kawasaki site Race tech is right



*edit* Actualy mx tech doesn't go as far as 97 so I had to use 2000. Kaw say .43 for 2000 kx 250 so there is no point in changing.
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Post by canyncarvr »

You may have read of some that don't like the bleed idea at all. It does seem a bit odd to gap the stack away from the piston. If the point is to control oil flow why would you intentionally defeat the control process?

There's other 'stuff' going on besides the MV...like the base valve (BV). They do work together. If you consider the BV to be on the slow side and the MV to be on the fast side..it does stand to reason that you would want the MV to flow somewhat unimpeded to the extent the BV works 'first'. I have not found that a bleed type MV compression setup lets the suspension 'shoot through' the first inches of travel.

Anyway...it all goes back to it all being a matter of personal preference. It'll be interesting to read what you think of the result of this fork foray.


You're basing your spring info on what is noted as OEM? That's a shot in the dark. If the forks have already been fussed with (as evidenced by the piston port marks on the 20mm shim), you would have to consider the springs to not be OEM. Most riders would replace the springs before they took the cartridge apart.

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Post by muddertrucker »

Considering the fact that I was supposed to ride them the way I got them first and modify em to see the difference, I figure I've done quite a bit as it is. I haven't even swaped the stem from the 97 to 02 bottom clamp yet. My BV is already modified.
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Post by canyncarvr »

??

Do I smell some umbrage? Is it being taken, even?

:hmm:

Re: 'Most riders would replace the springs before they took the cartridge apart.'

That's not a ding on you for anything. Meaning of it is: Your valve stacks appear to have been changed. That having been done, it's reasonable to consider that the springs have been changed, too.

..in which case whatever the OEM rate is supposed to be, that fact doesn't really have any bearing on what your springs are.

If they are .46s, how would you know?

The way to tell what the rate is of a particular fork spring is to test it.

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Post by muddertrucker »

Eventualy I'll get em instaled and them I'll know if they are to stiff or not. Not that it means enything at all but they are exactly the same length as the ones in my 97's. I'll be pulling the other fork apart soon to see if the MV is set up the same way as the first one was.
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Post by IdahoCharley »

After market springs normally have a rate marked on one end of the spring FWIW. Need to look closely because their not stamped into the spring very deep. That said - CC is correct i- measuring springs rates will give you an answer and you can normally measure them just buy using a bathroom scale.

P.S. Something stiff that fits freely within the spring (e.g. wood dowel, plastic sprinkler pipe, etc).
1. Mark off spring's relaxed zero point on dowel
2. Mark off several points on dowel - i.e. 2 and 4 or (3 and 6) inches from zero point (or some other multiple of 2 works)
3. Zero scale with spring and dowel resting on it
4. Fashion a tool to use to compress spring (large washer or something more elaborate) which fits over the dowel but squarely on the spring
5. Have wife, GF, kid or friend tell you when you compress the spring - when the top of spring is exactly at the first mark - you should have your head over the scale and record the scale's reading. Repeat the same procedure for the next mark. (The second reading should be double the first reading - if not either average reading or redo test)
6. Perform the math - inches to mm and lbs to kG - then divide to determine spring rate :wink:
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Post by skipro3 »

That's the midvalve??
Image

I thought it looks like the base valve...
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Post by canyncarvr »

That's what you get for having had (note past tense) a thought, ski.

Lots of things...but a couple............

The nut and cupped washer..look at their location. The BV nut and washer are together.

The MV has a seal (looks like a fork slider bushing) on the edge of the piston...'cuz it goes up and down..being attached to the rod, running INside the cartridge. The BV doesn't move, so the piston isn't bushed. It has o-rings.

The key to telling the two apart is that they come from quite different places in the fork! (heh heh)

That and the compression/rebound stacks are on opposites sides of the piston. Surely you can tell that by looking......right?


OK...kidding about that part.


Re: Spring rate markings

Not to be argumentative about it..but I have had no such marks on most aftermarket springs I've had my hands on. ..which ain't millions of them, but a few sets. That is not to say I've NEVER seen a number scratched on the ends..just not usually.

Consider this: You are checking a couple of spring sets, one set is supposed to be .38kg/mm, one set is supposed to be .40kg/mm. The difference between these two spring sets is 3/4 OUNCE of pressure with FORTY THOUSANDTHS INCH of movement.

Good luck with that.

But...my math is probably wrong..... :wink:

I was obscure on the point I thought I was making...

Given the two spring rates noted above..the differences are very small when measured at spec values (.38 compared to .40 per mm). The two spring sets will show about 2lb6oz difference using ICs 2" compression idea.
Last edited by canyncarvr on 02:38 pm Aug 20 2009, edited 1 time in total.

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Post by skipro3 »

Bump....

So what'sup with the RB setup?
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Post by muddertrucker »

This is what it looks like. I used the same pattern as the hole in the cartrige shown above.

[img][url=http:800:600]http://i85.servimg.com/u/f85/11/15/73/95/pictur16.jpg[/img][/url][/img]

It's not pretty, I might file it down some more to make all the petals even.
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Post by canyncarvr »

What can be done to index the thing? Would it be possible to put a little roll pin in the cartridge? Is the spring base thick enough to hold a pin. You could use a press-fit locking compound...like some steering stems have been pressed in with.

Looks good!

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Post by muddertrucker »

Once the tension from the spring is aplied to it I don't think it would move. If I just make sur the holes line up before putting the spring in I think it would be ok. I had tought of a spring pin though.
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Post by canyncarvr »

Every time a spring is compressed, it tends to twist. I don't know that it would stay...or wouldn't stay. I would prefer it HAD to stay because I STUCK it in place..then I wouldn't wonder if it moved or not. :wink:

Too bad it couldn't be keyed somehow..a protruding tab made to fit into a slot cut into the seat.

You'll come up with something.........I have faith. :prayer:

I know...Gorilla glue!! :cool:

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Post by IdahoCharley »

I should have posted a picture of my daisy pedal - but I don't think I took any pictures. You cut quite a bit more than I did from the restrictive plate - not saying you did bad (oil flow is good) but I did wonder whether or not I would have enough pedal to support the spring and I have twice the pedal you have. Mine has stood up with no problems for a couple of years FWIW. The other concern I had was the area under the modified restrictive barrier appeared to be aluminium on my CR KYB forks and I did not want my springs to distroy it.

Concerning measuring spring rates per my previous posting - using s bathroom scale is not the same as a spring scale but you should certainly be able to tell a difference of a .2kg/mm from say a .38 to .40 spring if you read scale accurately at two different increments and your spring is compressed close to the correct amount. You will be reading something along the lines of it looks like it is between 42-43 lbs at 2 inches and about 85 lbs at 4 inches (.38kg/mm) verses it looks like 45lbs and maybe 89 or 90 lbs. (.40kg/mm).

This method should NOT be used to determine - is it a .395kg/mm spring or a .40 kg spring - unless a slightly plump wife or GF is reading the scale - then and only then - you can rest assured that provided you can hold the spring steady for a couple of seconds the differences can be measured down to .000001 kg/mm based upon ANY bathroom scale. :lol: :lol: :butthead:

If your anal and attempting to be a precise as possible - perform a slot cut or notch the dowel for the washer to 'feel the compression point'.

Disclaimer - This method is not 100 % precise for sure - but when you buy a used bike and are attempting to identify approixmate rate of the springs or have purchased springs and are attempting to verify did I get the rate I though I purchased - it works well enough for many peeps.
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