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'03 KX 125 woods recommendations(shims)

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Just wondering if I can get some help from all you shim shufflers out there...

 

Riding a 2003 KX 125 east coast woods only, some hare scrambles.  I'm a C class rider and 145 lbs without gear.  According to a few different spring calculators my spring rates are pretty close, the fork springs are only 1 rate too stiff.  I'm on a budget, so I think I'll keep the springs for now.  As usual it seems, my problem is just plain harshness on the front end.  It feels like I'm only using about 4" of travel and the front wheel deflects off of everything.  In general the front end just feels like dead weight, and it's hard on the hands for sure.  Just got the compression valve out of the fork and it's all stock, in fact I'm pretty sure the oil was never even changed judging by the description of the OEM oil on other posts here.  I can't make any of the local races for about the next 2 months, so I'm open to some trial and error and can get the base valve out of there pretty easily now- so if someone can give me a starting point I'd be super grateful.

 

Here's the comp stack-

 

Check-valve shim

 

Base Valve

 

24 x .15

24 x .15

24 x .15

24 x .15

24 x .15

24 x .15

24 x .15

22 x .15

20 x .15

18 x .15

16 x .15

13 x .15

11 x .25

 

Do I need to list anything else?  I didn't have time to get the cartridge apart today, and I'm not sure if there is a mid-valve.

 

Thanks in advance.

 

 

-Chris

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Change all the 0.15 for 0.1

  • Like 1

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Also take 3 - 23x.11 shims off the rebound. (stock is way too stiff) Opening up the float on the midvalve to around .4 or .5 helps too.

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Change all the 0.15 for 0.1

If I do this, will I need to make up the difference in stack height or is not enough to worry about?  Also, being on a budget, is there anyway to substitute your recommendation by just removing or re-arranging the .15's?  I noticed on some of the other posts that people frequently say to remove some face shims.  A good selection is something I definitely want to have though so maybe I should just stock up now....

 

 

Also take 3 - 23x.11 shims off the rebound. (stock is way too stiff) Opening up the float on the midvalve to around .4 or .5 helps too.

Cool, I'll try that.  Still haven't cracked open the cartridge, hopefully get to it tomorrow.

 

Thanks

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These are KYB open chamber, right? Would do the base as recommended, but the biggest change will come from the mid. Hopefully you can pull a face shim from there and open the float a bit.

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Chris-

I have the same forks on my Husky WR300, ride east coast enduro and scrambles, and am sorta close as far as weight and speed. I've done a lot of messing around with my forks, and I think I have a really good setup now.

Also, I will say that mog and James both posted some good advice.

Also, C-P is right about the mid. I don't know what the stock float is on your particular model, but I believe that the mid is the source of a lot of harshness on these forks. You're absolutely going to want to open that up to make some changes, and while you're in there you can adjust the rebound as James suggested.

Here is what I would recommend:

Base:

24.1 (4X-6X)

12

22

20

16

14

12

10

Reb:

Remove 3X face shims (as per James L)

Mid:

Float = 0.8mm

24.1 (3X)

22

20

18

16

14

10

Valving logic is showing a factory bleed shim on the mid. I haven't done that model and year so I don't know if yours has that, but just be aware that you might find it one in there. I would remove it, but you'll have to be sure to lighten the rebound if you do that.

I would highly recommend opening up the cartridge and adjusting the mid and the reb. However, if you can't/don't, you can try pulling 4-5X face shims off the base and see how it feels. It will be better, but far from as good as you'll get if you open the cart.

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However the mid on the 03 is a nightmare to get into

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Yeah, you have to drill the peens and then break the seal on the cartridge cap. Thanks for making these easily serviceable, KYB! :banghead:

 

You can definitely make them more woods-friendly by adjusting the base as per mog/my suggestions, but the midvalve dominates the highspeed damping so much that I don't think you'll ever get them to be truly woods plush without opening the cartridge. :(

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These are KYB open chamber, right? Would do the base as recommended, but the biggest change will come from the mid. Hopefully you can pull a face shim from there and open the float a bit.

Yes, they seem to be open-chamber.  At least no bladders/tanks like I have read some of the other KX forks have. 

Yeah, you have to drill the peens and then break the seal on the cartridge cap. Thanks for making these easily serviceable, KYB! :banghead:

 

You can definitely make them more woods-friendly by adjusting the base as per mog/my suggestions, but the midvalve dominates the highspeed damping so much that I don't think you'll ever get them to be truly woods plush without opening the cartridge. :(

Thanks a ton for the recommendations.  I'm looking to get these forks as perfect as I can, so I'm going to try anything and everything as long as I have the tools.  I spent 6-7 years in auto/moto tech dealerships, so my mechanical skills are good, I just really didn't ever touch dirtbikes and the only suspension work I did at the previous shop was just plug-and-play Racetech gold valves.

 

Kyle(and others here)- What are you guys using to come up with these recommendations(besides experience)?  I looked into purchasing the Restackor program, but not sure if I understand the way it works enough to actually put it good use yet.  

 

Also, another question....I may be moving to New Mexico/Colorado next year.  How does a setup for desert riding differ from woods?  I know the 125 is probably a bad choice for desert riding, but I really like my bike, and may just keep it for a second spare.  I'll be trying to get the cartridge apart today, so I'll let you guys know how it goes.  

 

Thanks

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Since these forks are basically exactly the same as what I have on my own bike, and I ride in similar terrain at similar speed to you, a lot of it translates pretty directly.  However, a lot of general things translate between different forks, with corrections for port geometry, rod size, weight, speed, etc.  For example, I can run a setup similar to what I'd run in OC KYBs on Marzocchi 45s and have it work pretty well, with some small tweaks due to piston/port size differences.

 

I also have a copy of ReStackor.  It takes some "nerdiness" to get the correct inputs into the program and understand the output, but once you get it figured out it's a good way to help quantify some of the things you get through "feel" and for comparing different setups.  It depends if you're into that sort of thing or not.

 

I am not that familiar with desert race setups.  In general I'd expect them to be stiffer because of increased speed, but not full MX stiff because they still need plushness for rocks, etc.  If you get a woods setup sorted out for where you are now, I bet you'd be 75% of the way to a good desert setup, both in terms of the setup itself and the knowledge you'll gain about how different changes effect the way it works/feels.

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Awesome!  Well I'm going to start with your list and ride soon hopefully.  Question though.....

 

I just looked at my cartridge, and can't see anywhere on the cap where the peening might be.  Any ideas?  It's completely smooth all the way around.  Sorry, I don't think I can get a picture anytime soon, my phone camera is broken.  

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My answer to your question is the same as Kyle's. I have the same forks on one of my bikes... a KX125/KDX200 hybrid. The forks are actually off of an 04 KX250 and I removed the bladders and sealing ring at the top of the cartridge. So basically we have the same forks.

I used restackor to set it up as close as possible to how I have my YZ250. It's a good program. Easy to screw up the data entry, lol; but, it saves a lot of time in guesswork after you get the hang of it.

I've never set up a bike for the desert. I would think that you would have to least have to stiffen the low speed compression, probably the rebound a little too. As Kyle said you should be 75% there after setting it up for the woods.

Edited by James I

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Here is a picture of unscrewing the top of the cartridge:

 

IMG_20130701_175916_153.jpg

 

Note the two "special tools" being used; clamp blocks for the OD of the cartridge, and a special "socket" that fits into the area where the spring seat sits (this easily taps off).

 

If the unit is peened, you'll see small dimpled near the top of the cartridge tube, right below the shiny CNC machined cap.  The cart in the picture above does not have the peens.  There are some good photos of that here:

 

http://www.thumpertalk.com/topic/421304-yz-mid-valve/?tru=IVcgK#entry3791049

 

Some more info here:

 

http://www.thumpertalk.com/topic/595624-tell-me-how-to-get-this-cartridge-apart/#!IVl4Y

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Arrrrghhhh.....

 

Having a hell of a time getting the top off.  I don't have perfect tools for them, but am still able to get some good leverage on the wrench and it won't budge.  Even tried heat to no avail.

 

With my homemade tool, I won't be able to get any kind of impact wrench on it to shock it loose which is what it seems like it needs.  Any other techniques I can try?  I might have to take it to a shop and see if they can crack it.  

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Yeah, it's a pain.

 

You need to get it pretty hot to break the factory loctite.  Just be careful not to melt/damage the damper rod seal in the center.

 

After that, mine still took a decent amount of force to break loose.

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Gotcha.  I only used a pretty small heat gun, but have a propane torch somewhere I'll try that.  I also tried rolling the cartridge on its side and lightly tapping on the threaded area with a hammer back and forth.  I must need some more elbow grease!

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Yeah, I used open flame on mine (propane or MAPP, can't remember).  I didn't cook it for 5 minutes, but I was definitely putting some heat to it.  I bet it was too hot to hold onto when I was done.

 

I don't know what threadlocker they use, but for reference Loctite 272 (high strength red) has to be heated to 250 C for disassembly; that's HOT!

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Got it!

 

Used a propane torch for a minute or two....holy crap it was on there!  For a second I thought I could feel the cartridge body twisting, but it looks good.

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Be very careful roving the peen on the rebound side of the mid,it has very few threads

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Yes, I definitely noticed that.  For the other leg, I'll probably try to remove less material, I cut it kind of close on this one!

 

A search may get me some pics, but I'm still wondering the best way to increase the float in the mid-valve.  Any quick answers?  I can look it up after work if not.  Just trying to think of ideas while I work.  

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