KX Fork Conversion Questions

[KDX200Kev]

Calling on all KX Fork Conversion Experts

Well I did it. Its in the mail. I purchase a set of used KX 125 forks (48 mm :cool:) and the brake system. Both of these items are off a 2003 model year. I have reviewed all the thread on this subject, and this has help me greatly to understand what is involved, but I still have questions.

I still need to buy a KX front wheel. The 2003 model year hub part number is different than the 1999 - 2002 KX hubs. However the axle is the same. Am I stuck having to used a 2003 KX hub? Do I need to rebalance the bike after installing the forks if I ride mostly desert? If so should I have the front lowered a half inch or install the Devol transformer pull rods to raise the rear end or use KX dog bones? If the KX dog bones work, which year? I appreciate your response in answering my questions.

 

[kx250kev]

Ok, I'm no help on this conversion, but I just wanted to say.....nice username. Maybe I'm your evil twin? Just kidding. Wait a minute, you have a KLX110 too. This is getting wierd....kev out.;)

 

[KDX200Kev]

Ok, I'm no help on this conversion, but I just wanted to say.....nice username. Maybe I'm your evil twin? Just kidding. Wait a minute, you have a KLX110 too. This is getting wierd....kev out.;)

As the saying goes great minds think alike :)

 

[KDX200Kev]

Anyone???

 

[KDX200Kev]

Thanks for the responses. I will measure the before and after rake/trail measurements to understand the change. Preliminary calculations puts the rake at plus 1 degree and 0.8 inches increase in trail. This is considering the 1 inch increase in lenght (35 to 36 inches) of the KX fork. Given that the KX bottom triple clamp is 6 or 7mm thinner then the KDX's and the forks can be raised 10 mm in the top triple clamp the overall lenght will increase 0.5 inches. Thus, this will result in the KDX rake increasing approximately from 26.5 to 27 degree and the trail from 4.3 to 4. 7 inches. It is possible the trail might be slightly more since the location for the axle connection may be set back farther then on the KDX. However the offset of the triple crown may be less then the KDX resulting in reduction of the rake. The KX triple clamp offset was reduced by icreasing it from 22mm to 25mm for 2003 model year. I don't know how this compares to the KDX yet but it may make a difference. As far as rate and trail goes I don't think the change will make the bike dangerous to ride. Consider that the KX 500 has a rake of 27 degree's and trail 4.6 inches and the new 2006 KX250F has a rake of 27.5 degrees and a trail of 4.7 inches. The KX swap rake/trail change is still in the ball park at least compared to MX bikes. Thus for desert riding it will be a good thing. Now if I find some good woods riding, which I wood like to do then I will bring the rake back by shorten the dog bones. Not sure of the lenght I should use but I am guessing 110 mm compared to the stock 112.5 mm ones. I have come to the conclusion I will need a 2003 hub since the rotor is different then the 2002 model and I have the KX 2003 brake calipers. As far as the shim and KDX stem transfer thats all been described well in other posts. Now if only the postman would deliver my forks. :ugg:

 

[Woodsquest]

Press the steering stem out of the KDX triple, and press it into the KX triple... Troubleshoot from there...

Do this and you could get yourself hurt.

**Edited by Mully******
There are several guys here that have done this mod and are willing to walk you through every step. Goodluck!!

 

[Green Hornet]

Remember the KX models have a longer swingarm, so that will make up for the rake & trail. Like woody said, becareful.

 

[Mully]

KDX200Kev,

There seems to be some who think you need to be carefull when doing this conversion, yet sit back and offer nothing in the way of advice. At this point I am going to challange them to step up and give you the imformation you are needing.

Come on fellows, show me what you have, you know who you are...................... :)

Mully

 

[Green Hornet]

KDX200Kev,

There seems to be some who think you need to be carefull when doing this conversion, yet sit back and offer nothing in the way of advice. At this point I am going to challange them to step up and give you the imformation you are needing.

Come on fellows, show me what you have, you know who you are...................... :)
Mully[/QUOTE

When you have more questions than answers, I would tend to think caution would be a sensible factor. So if you have advice or knowledge of this topic lets hear it.

 

[KDX200Kev]

KDX200KEV: If you really want to know all there is about the KX fork mod and I don't get banned or edited to heck and back, let me know and I'll cut and paste all the info from that other site for you here.

I would really appreciate if you would post the information. I think others would be interested in viewing this information. Thanks in advance for your effort.

 

[Woodsquest]

I would LOVE to post the information KDX200Kev, but as you can see from the quote you have in your reply, my messages are being not only edited, but completely deleted by someone, probably Mully.
Com'on Mully, you challenged me to show you what I have. I did and you deleted it. What gives? What is it that has you as a moderator so concerned?

Let me try again:
Of course, start by getting all your KX front end components together. Here is a cut and paste of how to do the KDX / KX stem and triple clamp work:
With both the KX and the KDX lower triple clamps in hand, press the stems out of each and press the KDX stem into the KX lower triple clamp. Now the KDX bearings will be used. The KDX lower bearing is pressed on to the KDX stem, (now attached to the KX lower triple clamp) and the whole thing slides up onto the KDX frame and into the stock KDX bearing race. (which was never removed). The KDX upper bearing is placed over the portion of stem sticking up out of the frame opening and into the upper race. It now becomes obvious that the stem is too long when you place the KX upper triple clamp over the protruding KDX stem and the stem sticks up through the KX upper triple clamp with more stem than threads. A spacer is used to be able to apply tension when tightening the upper stem nut. I used the stock KX stem nut since it was big enough to just slide over the KDX stem and was about the right thickness to now allow the KDX nut to pull down tight to the upper triple clamp without bottoming out. Put the KX stem nut over the KDX stem, then the KX upper triple clamp, then tighten down with the KDX nut. Because the KDX stem is a smaller diameter than the KX was, there will be some slop when putting the upper triple clamp on. Some simple shim stock material works great. Trim up a piece of shim stock to just wrap around the stem and slide the KX upper triple clamp over the KDX stem wrapped in the shim stock. I used brass but can't remember the thickness. Maybe .025? Man, that's all there is to it! Now that the triple clamps are mounted to the frame, slide the KX forks on, attach the wheel and brake, handlebars and controls. Easy peasey, as they say.
The pressing work is about $15 from any machine shop and the shim stock was about $5 from a hobby store that specialized in model railroading. Any questions just let me know. *** sorry *** I will try cutting and pasting other info for you if you wish as well. Good Luck!

 

[Woodsquest]

MOre cut-n-paste: Use what you can and ask questions.

**Why, yes I can*****

Hey. Thanks for the write up. So the shim part is JUST on the upper triple
clamp, correct? I think I always cringed when I saw shim and stem, so I
quit reading previously. I was thinking the shim was in the lower triple
clamp, where the stem was pressed in.

On my bike, the stem pressed tightly into the lower triple clamp. From year to year on the KX lower triple clamp this is off by just a bit. I had one that way and had the hole in the triple clamp knurled, like how the kick starter knuckle is splined but not quite as deep. It cost me $5 at a machine shop that specializes in building race motors. Knurling does not remove any material, it only reshapes it to a ridged opening instead of a smooth one. The high points of the knurl now will allow the stem to fit tight. I think that any triple clamp newer than a 1996 will be a press fit to an H model KDX and one 1996 and older will be a tight fit but would benefit from a knurling. The machine shop in my area does this for wrist pins and pistons so that they fit snug and the bearing at the top of the rod will work against a non moving wrist pin. This same tool is what he used on my first conversion, a 1996 KX triple clamp. I later changed my KX triple clamps to an after market brand; Applied Racing or BRP, I can't remember. That needed 20 tons of pressure to fit the stem to the triple clamp. If you do the mod, be sure you check the fork tube size will fit the triple clamp as well. Not that a little machine shop work wouldn't be able to get everything to work right for only a few dollars, but it does save time and gets you riding much quicker. You sound like a fair garage mechanic. This mod is easier than rebuilding a fork or shock. I would rather do a KX / KDX fork conversion than to rebuild my rear shock any day. Heck, a top end job is several times harder to do with the KIPS and all compared to what it took me to swap front ends.

 

[KDX200Kev]

Sorry, I am the quilty one for shortening your quote on my reply. I was just trying to focus my reply. Please accept my apology.

Any additional info you can post would be great. I went to the other site but did not find the location with the pics. I tried registering but have not received my e-mail response to do a search. Cruising the site I notice that you also have the KX 2003 forks and use your existing caliper. Was there any problems with using your existing caliper? What KX model year front hub did you get? Did you shorten your dog bones to raise the rear to bring back the geometry? Your response is appreciated.

 

[Woodsquest]

www.kdx.woodrider.netSorry, I am the quilty one for shortening your quote on my reply. I was just trying to focus my reply. Please accept my apology.

Any additional info you can post would be great. I went to the other site but did not find the location with the pics. I tried registering but have not received my e-mail response to do a search. Cruising the site I notice that you also have the KX 2003 forks and use your existing caliper. Was there any problems with using your existing caliper? What KX model year front hub did you get? Did you shorten your dog bones to raise the rear to bring back the geometry? Your response is appreciated.

You misunderstand:
You are quoting a post I made that is now deleted. See for yourself: Find the post where you quoted me. It's gone.

 

[Woodsquest]

Where in California are you Kev? Anywhere near Sacramento? If so, I can provide you with hands-on help. I've helped several folks do their KX mod in the past few months; maybe 4 or 5 beside mine.

 

[Mully]

I missed that, sorry, but to answer that question in particular;
Because the constant flow of effective information maximizes the chances for the threads success and minimizes the cost of the websites hardware. As a serious resultant complication, a large portion of the interface coordinating communications necessitates that urgent considerations be applied to any discrete configuration of the web interface subsystem rationale.

That help?? ;)

 

[lepper]

I hear ya.... Sure...things got off on the wrong foot... I agree with that, and it seems there are (spies) for lack on a better word on both sides. But the other side allows DRN talk and links... I know they appear funny but at least they are allowed (I'm sure that would be rectified if at least the mention of the other site was allowed here). There is a lot of great information out there and it needs to be shared... not just copied and pasted from one site to another. I don't want to see anyone get hurt and try something just because of some feued going on between two different sites. Do you?

Let's call a truce .... what do ya say?

 

[canyncarvr]

There is more to the KX fork conversion than a couple of answers to a couple of questions. Depending on the year of KX 'stuff' you use, or the years of KX 'stuff' you mix-n-match there are quite a few problems...well, if not problems, certainly questions that need answers.

Worry a whole lot less about .5º changes in rake and fractions of an inch changes in trail. You're not going to do a whole lot to fix that anyway.

Get your KX 'stuff' from the same model year if you can. A write-up that covers every conceivable possiblity of conflict in the process would be pages long and would probably be mostly useless in answering a particular question.

Actually, other than some plumbing, Zerotact summed it up pretty good.

If you have a specific question, what is it?