KX fork conversion recap?

Questions and comments about converting to beefier forks..
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Indawoods
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KX fork conversion recap?

Post by Indawoods »

Hey guys... I AM going to do the KX fork conversion and I need a recap of what I need to do to make 'em work. Do I have to edit the stem and that's about it or what? :rolleyes:

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I made this a Sticky because it is a good primer!
Last edited by Indawoods on 12:04 am Sep 27 2005, edited 1 time in total.
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Post by m0rie »

I think SkiPro3 had to shim the stem with some shim stock to get a good fit. Also the brake line routing can sometimes be an issue from what I recall.

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Post by KDXGarage »

I think he got his lower triple clamp knurled, then the KX stem pressed in, then some sort of spacer for the top bolt/nut.
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Post by skipro3 »

I'll take the time and provide you a complete write up and include some photos as well. It is EASY!!! Believe me, if I can do it, anyone can. Look for it sometime tomorrow. Time to go home!!
Jerry

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Post by Indawoods »

Excellent Ski.... Thanks! :grin:
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Post by canyncarvr »

But...but...not all KX conversions are the same. The model of KX you use will matter when it comes to 'how to?'

...like the knurling part.

Inda: Where you getting your KX stuff from? I've looked quite a few times for auctions and things going on.....have YET to see what I need. I don't want to buy it piecemeal too much. I've seen wheels (no caliper...no rotor) and forks (no clamps) and such.

Heck...I even asked FRP about their Ohlins setup. ...got no answer of course, but I DID ask!

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Post by Indawoods »

I got eSnipes on the parts I need at eBay right now. So ya'll back off 'em! :mad: I think 01-03 are the same parts, 125 and 250 other than the spring rate. And yes... all parts. I have the wheel already! :lol:
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Post by KDXGarage »

I think the bearing and stem issues started with the 1992 models.
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Post by skipro3 »

Here is the story of how I added KX forks to my KDX220R:
I got a front end from a 1996 KX125 off eBay for $400 including shipping. It came with the triple clamp / stem, forks, front wheel assembly, axle, and full brake set-up including master cylinder assembly. I swapped the whole thing out but didn't need to. Here's what you need. I know that the KX125 or KX250 from at least 1996 to present are going to work.. You will need to use a KX wheel / hub. The KDX will not work. Axles totally different, bearings too. Once you have the forks / t-clamp / axle and wheel, take yours all off. Remove the handle bars, front axle, wheel, each fork, then the t-clamp. Take your KDX t-clamp and the new KX one to a machine shop and have them press the lower bearing and stem off of each. My 1996 KX triple clamp needed to be knurled for the stem to fit tight. Later years don?t seem to need this step. I recommend getting the later year triple clamps as that is one less thing you have to mess with. If you do get a ?96 triple clamp that needs knurling, have a machine shop knurl the inside of the KX t-clamp. A knurling tool is a cylinder with ridges on it that when forced through the stem hole on the lower t-clamp will make ridges like your shift lever uses. No material is removed, just rearranged. Have the stem and bearing pressed back on. Don't forget the circlip on the bottom of the stem. It is used to prevent pressing too far on. Now for the reassemble. Grease the lower bearing. Insert the lower KX t-clamp (with the KDX stem that was pressed on) into the bikes head, slide your KDX upper bearing on after greasing, put on the dust cap from the KDX and the stem nut from the KDX. Seat about 20 ft. Lb. of torque, loosen, then just past finger tight. Put a spacer on over your stem nut. Washers with a big hole in the middle will work but I discovered that the KX stem nut, being larger, slipped over the exposed stem and worked great. If you forget or try to not use a spacer, your handle bars will not sit on their mounts right. At this point you have the lower t-clamp mounted and tight. Put the KX top t-clamp on. You will see it is a sloppy fit. Go to a hobby, craft shop or a model train / airplane store and get .025 thickness of shim stock and use it to reduce the hole diameter in the upper triple clamp so your KDX stem will fit snug. I used copper because it is easy to cut, but aluminum or brass are just as good. If you can't find any, I will send some to you. Anyway, cut with tin snips or some old scissors, and shape it using the left over KX stem. It can be a little short, and not make it all the way around, it won't matter. Put this into the top t-clamp hole and slip over the stem. If the shim pops out a little, tap it in with a nail set or something. It's not a tight fit, nor should it be. Put your KDX washer and top nut on to the stem and hand tighten. Put your forks on and tighten to the t-clamp but don't torque down just yet. put the KX front wheel on with the KX axle. You can use the KDX brake assembly. The difference in the brake assembly is mainly the routing of the brake line. It is much cleaner using the KX. Put the front brake on, rotor, line and master cylinder. Now, with everything in place, start torqueing down all the hardware. Re-install handle bars, torque and ensure all cables are routed correctly. Fire that bad boy up and hit the trail, you're done! Here is a over view:
Materials:
KX forks
KX t-clamp
KX wheel and axle
.025 shim stock to reduce the KX top triple clamp opening to match the KDX stem
Washers or the old KX stem nut as a spacer so the stem doesn?t bump up against the handle bars
Labor:
press off old and new stem and bearing.
Press the KDX stem and bearing on to the KX lower triple clamp. (the pressing with knurling cost me $25.)
Assemble lower t-clamp, upper bearing, dust cap and KDX stem nut on your bike to seat bearings.
Install washers or KX stem nut as a spacer for top nut clearance under the handlebars.
Fabricate a .025 shim for the slop between the upper t-clamp hole and the stem and install.
Attach top washer and nut
Attach forks, wheel, brake, and handle bars.
Check cable routes for clearances and no binding / pinching.
Ride fast and hit something big. You will be amazed.


As a final thought, play with the fork height in the t-clamps. Mine are now about 1/2 inch over the top clamp. The KX forks are a taller ride than the KDX and this will change your geometry if you don't drop the forks a little.
I hope I haven't totally confused you. It is an easy upgrade. It took me about two hours but that was because I was polishing and cleaning everything to like new condition. I?ll post up some photos once I find where I put them.
Jerry

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Post by Indawoods »

Hey Ski... How about Knurling the top to avoid having to shim it? Not to the size to have to press it on... just to take up the extra space...
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Post by skipro3 »

You need to "float" the top triple clamp until the forks are bolted up in order to keep the top clamp in perfect alignment with the bottom clamp. Otherwise you will put a bind on the upper fork tubes that could result in some stiction when the axle is torqued down.
Think of it this way:
As you slide the new fork into the lower tree, it goes up and needs to line up with the hole in the upper tree. If the knurled upper doesn't line up just right, you will need to flex the fork tube to get it to fit into the upper tree opening. keep the upper tree free to rotate untill the fork is up into it and you torque down the pinch bolts. Then tighten the nut holding the upper tree.
The order I do mine is: Front axle torqued down first, then lower tree pinch bolts, then upper pinch bolts then upper tree nut. If that's wrong, someone tell me why.
Jerry

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Post by Indawoods »

If it binds... then why couldn't you use a step bit to take out the offending material? Everything I do custom, is well... custom. It won't work on your... but it will mine because I fitted it to it. Know what I mean? It seems it would be centered from the get go... then measure the gap on the bike and knurl accordingly. Am I way off base here???? :neutral:
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Post by skipro3 »

I have not seen the knurling device close enough to tell if it is adjustable or there are several sizes, like drill bits. As long as the stem stays centered in the upper clamp's hole, is able to be lined up with the lower clamp then everything should work fine.
I'm looking forward to getting a ride report from you once you have this all done.
Jerry

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Post by Indawoods »

SOMEHOW... my entire post didn't get posted... :shock: What I meant to put after "get go..." is :assemble the forks into positions as if you were going to mount them permanently "them measure gap ..." You would have to be able to have some kinda idea what the tolerances are on a knurling job. Otherwise it wouldn't be a machining process ... right? :neutral: Image
I'm a 'puter guy but did take machine shop as a youth and it seems to me everything had adjustments. Another alternative may be that you get a sleeve made to take up the difference. That may involve boring the top clamp and pressing in a sleeve. I just hate the thought of shimming the difference but I will get a better idea of what I have to work with after I get the forks in my grubbies.... :grin:
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Post by skipro3 »

Nice depiction of what knurling is. As shown in your diagram, no material is removed, just reshaped. Printing out and taking this drawing to any machine shop to explain what you want done will go a long ways. Machinists don't take kindly to folks using wrong terminology or bad discriptions. They are kind of like a frenchman when trying to talk to them in your highschool french; They claim to not understand a word you say until you say it exactly correct.
Anyway, back to shim. You spoke of making a sleeve to take up the difference. The shim IS a sleeve, albiet a very thin one. Believe me, it's not worth the effort or money to have the clamp hole opened larger and a perfectly sized custom sleeve fabricated and placed. You will see when you get to the stage. Just have the shim stock handy. If you don't like it, then go the sleeve way.
Jerry

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Post by Indawoods »

Wow... now I have triple trees and a rim... maybe someday, I could buy a bolt or something... :mad: Outbid on the forks by $2!
Last edited by Indawoods on 09:39 pm Dec 04 2004, edited 1 time in total.
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Post by johnkdx220 »

Excellent description ski! :supz:

I installed a 1997 kx250 front end. I followed almost the exact same process except for 2 details.

a) The machine shop didn't have to knurl the kdx stem. 16,000 pounds of pressure made was required to press the kdx stem into the kx lower clamp. Oh, by the way, tell the machine shop to heat the kdx triple clamp before pressing the stem out, there is industrial strength lock tite in there. (KHI seems to use more lock tite than grease... that's another story...)

b) I installed a greasing zerk on the steering head in the middle of the process. Add 20 minutes and 50 cents to skip row 3's description :wink: From that point on, you only have to worry about cleaning the thank you grease spits your new bike will make on the back of your fender. Don't worry about having to change the bearings.

Break line routing... Since I ride very rough terrain, I prefer using the stock kdx cable routing. The "under the fork" KX routing seems to be more prone to damage.

my 2 cents.
KDX220 (RB'd, EFM Autoclutch, FMF Rev, KX front end... Crash proofed and crash tested tOO often !)
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Post by skipro3 »

Thanks John. When the shop pressed my KDX stem out, it shot out so hard, the kid doing almost lost his foot. It was like a rocket!
I also put in a zerk. I wrapped the stem inside of the frame wtih an old cross brace pad so I wouldn't use up a bunch of grease.

Inda: Now that you have your upper triple clamp, you can size your stem to it and see what I'm talking about with the shiim to reduce the opening size.
Jerry

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Post by Indawoods »

Well... some guy saw I was second high bidder on the 03 forks and emailed me an offer for a set for $220 shipped. I told him SOLD!! :grin: So... now I gotta figure out if I need to sell my 01 wheel and get an 03 wheel because 03 stands alone as far as suspension. From what the guy told me (He works at a suspension shop out East)...it was the most advanced system Kaw made and almost exactly like the Yamaha setups. So, there may another chapter in the KX swapout saga. In 04 they went the way of the 97-02 style via Suz/Kaw. I don't know if any of this is true, I am just passing on the info.... But I'm excited to say the least! I love a challenge!~ :cool:
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Post by Indawoods »

Just checked buykawasaki and it appears the caliper bracket is the same, the caliper itself has a different part number but it may just be a slight design change and function the same... I guess I will find out. The wheel appears to have most of the identical part numbers also. This may be misleading but they look almost identical too. I don't have access to the blueprints to check measurements or I woulda! :lol: I think it will work..... BRILLIANT! :partyman:
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"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
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