Fork COnversion Questions From The Uninformed :)

Questions and comments about converting to beefier forks..
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ihatefalling
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Fork COnversion Questions From The Uninformed :)

Post by ihatefalling »

OK fork converstion pros....you've really got me thinkig about it.

Currently I'm on an H model with OEM forks.
I've got Gold Valves, stiffer springs, 10 weight fork oil.

I think I'm happy with the feel of the ride but, what I wonder about is stability/deflection. I ride a lot in loose rocks so I get kickers all the time. It seems like the guys on KTMs (USD forks) don't deflect as much.....seems that way but who knows.

Would you mind expanding on the ride change you felt when you changed over?

I don't have a lot of experience riding bikes with USD forks.

Also, I'm not wanting a firm feel like a lot of the KTMs I get to test ride feel like. I would like a little bit more of a softer ride, like I have now.

I've been reading a lot of the post about the conversion but it can make you dizzy. SO am I right in saying:

1) I'm going to need a KX or KXF front end which will include the wheel, caliper, stem and forks. I don't need the triple off the donor bike b/c I'll use my KDX triple.

2) Get with RB and have him press the "stem" out of the donor triple, put it in my KDX triple with the spacer things he's designed.

3) Reassembly is pretty straight forward.

4) More than likely the ride will be too stiff for me (150 lbs without gear). So I will need to have the "new" forks resprung? I don't know much about valving...will I have to have them revalved too?

5) I think I read that a KX125 front end might be a better fit based on my weight. True?

Feel free to expound to your heart's content :wink:

Thanks in advance for those that will take the time to reply. I'm just trying to get me head straight on effort, expense, time and result before I pull the trigger :supz:
2005 KDX 220
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Indawoods
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Post by Indawoods »

You will NOT use your KDX triples. They will not accomidate the KX forks.
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Post by ihatefalling »

Oh....my bad. I will need to take the KDX stem out of the KDX triples and put it in the KX triples...right?
2005 KDX 220
R&B Carb Mod
R&B Head Mod
Fork Swap - 99 KX125 Valved for B woods plush
FMF Gnarley
Airbox Mod
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Post by Indawoods »

Correct!
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Re: Fork COnversion Questions From The Uninformed :)

Post by SS109 »

>|<>QBB<
ihatefalling wrote:1) I'm going to need a KX or KXF front end which will include the wheel, caliper, stem and forks. I don't need the triple off the donor bike b/c I'll use my KDX triple.
You must use the donor triple clamps as they fit the forks you will be using.

2) Get with RB and have him press the "stem" out of the donor triple, put it in my KDX triple with the spacer things he's designed.

Correct.

3) Reassembly is pretty straight forward.

Correct again!

4) More than likely the ride will be too stiff for me (150 lbs without gear). So I will need to have the "new" forks resprung? I don't know much about valving...will I have to have them revalved too?
I'm running a .41 spring which is stiffer than the stock .38 and I weigh the same as you. I think its a good match with the stock KDX rear spring as the bike is balanced very well front to rear. To get the ride softer you will need a re-valve and maybe play with oil height/weight a bit.

5) I think I read that a KX125 front end might be a better fit based on my weight. True?

For you, possibly. However, you have no idea what rate of spring is in them unless the seller tells you so it could be stock or it might be for a 250lb guy! Like me, I bought '96 KX125 forks and they came with .41 springs!


The only regret I have with the KX fork swap was that I didn't get them re-valved from the get go. I have the compression and rebound adjusters all the way soft and it still isn't to my liking. Otherwise, they are the setup to have due to less deflection, less under hang, and more adjustment. I can only think of two negatives. One is that when the seals start leaking they LEAK! The other is that the top of the bike gets a little heavier. Not uncomfortably so but it was very noticeable to me.
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Post by G22inSC »

I would like to know why the change. I have just got back into riding (few years ago) after a 25 year drought. The kids are getting bikes for Christmas and I will be following them around for a while. I do not race by any means and mostly ride trails; however, I have gotten brave a few times and tried tracks with friends. No...I don't even attempt big jumps and/or triples. I have too many bones to break and bills to pay for those extremes. I can't decide between the springs and gold valves or just do a conversion. Were you happy with the spring and valves in the beginning? Did you get to the point where you could ride beyond the springs and valves or just want a change? Would I be just as happy hitting trails with kids and occasional tracks with the upgrade springs vs. converted forks? Just wandering what other peoples opinions are. Thanks.
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Post by Indawoods »

After farting around with your stock forks trying to get them adjusted for you with springs, oil, valving and such... it is just plain cheaper and easier to bite the bullet and get the KX forks and be done with it.

As you start to ride faster... the stock forks become dangerous IMO.
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Post by G22inSC »

Are 04-06 KXF forks suitable or are they totally different and too complicated as compared to KX forks? Is the conversion the same or more involved? Sorry for the questions, just don't know all the ins and outs yet and trying to plan. Thanks.
'05 Kaw KDX200 ('00 KX125 forks / '02 RM125 Showa "K2" shock)
'14 Yam YZ125(x) (oldest boy's)
'22 Yam YZ125X (youngest boy's)
'17 Yam YZ85 (soon to be FOR SALE)
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Post by ihatefalling »

That's where I am Inda. I like the way my suspension takes the hits but....sometimes feel the forks are flexing and allowing me to deflect everywhere. And you are right....it's starting to get dangerous at times. And of course those times are when you are going fast, so the risk is even greater.

I called factory connection today and explained to the tech where I'm at.....in wanting to keep the ride "feel" after the conversion but pick up the added control. He looked up some specs and thought that If I could pick up some 00-05 (03-05 preferred) KX125 forks with the stock springs I should be ok but, he said I would have to mess with the valving. But he had never heard of us doing fork conversions.

I've been looking on ebay but nobody has the "total package". So I guess I'll have to piece it together. There were some complete bikes on craigslist, but I would end up having to part them out afterwards to recoup some of the csah....that will be a pain.

Keep talking to me guys. Do any of ya'll agree with the racetach guy? Especially on the years of the forks? What about newer KLX forks...are they "better"?
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Post by Indawoods »

I can only comment of 03 and older.

I have 03 48mm forks. Personally, I think they are overkill. All the valving and such in them are overkill and they are TOO stiff. I like some flex but they do not flex enough. This makes for a harsh ride. I revalved them myself... and as they blow through the valves they are still too rigid.

I think the 46mm forks would be better and you could eliminate the mid valve altogether. These started in 96.

My brother has 95 KX forks and they feel good too. I never got real agresssive wit them but they seem to do the job just fine.

I actually plan to downgrade....
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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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Post by ihatefalling »

Thanks Inda and SS :supz: I still only have a small clue what you're talking about :cool:
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R&B Head Mod
Fork Swap - 99 KX125 Valved for B woods plush
FMF Gnarley
Airbox Mod
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Post by SS109 »

I definitely think the 46's are the better choice for the same reason Inda mentions. Also, they are a little lighter than the 48's. Yeah, it may not be much but every once/pound makes a difference!
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Post by ihatefalling »

OK...so from what Inda says, the 46s started in 96. DO ya'll know if they had an ending year?..... for a date range....

This is really starting to sahpe up. If RB can get that front wheel spacer mod worked out I just might be in business!
2005 KDX 220
R&B Carb Mod
R&B Head Mod
Fork Swap - 99 KX125 Valved for B woods plush
FMF Gnarley
Airbox Mod
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Post by OLHILLBILLY »

>|<>QBB<
ihatefalling wrote:OK...so from what Inda says, the 46s started in 96. DO ya'll know if they had an ending year?..... for a date range....

This is really starting to sahpe up. If RB can get that front wheel spacer mod worked out I just might be in business!
'96 thru '98. I'm using '97 forks on mine.
What front wheel spacer mod are you talking about?
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Post by Mr. Wibbens »

You don't get out much do ya?
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Post by OLHILLBILLY »

>|<>QBB<
Mr. Wibbens wrote:You don't get out much do ya?
So, I gather you don't know either?
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Post by Mr. Wibbens »

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Post by OLHILLBILLY »

Ok, only thing I'd seen was somebody a while back trying to make the whole different axle. I just used a KX wheel, and replaced the stock odo with a Trail Tech computer and didn't look any further. Haven't seen anything yet on RBs site about it, but once again, I haven't looked real close either.
I'll go have another look, as a friend of mine is wanting to use his KDX front wheel. I'll point him in that direction.
Thanks..
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Post by 99sr220 »

Just a few questions, if I can jump in.

From what I've gathered, the 96-98 are probably the best option because they are lighter and less harsh?

I am 185lbs with gear, would these forks suit me without having to revalve and mess around too much?

Also, was wondering about possible disadvantages. I've read the may not be as good in tight stuff or in sand. Is this the case or is it just a matter of tuning? I'm not great in sand, especially long straights. I would have thought that stiffer forks would be an improvement?

Thanks!
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Post by rbates9 »

>|<>QBB<
ihatefalling wrote:I've been looking on ebay but nobody has the "total package". So I guess I'll have to piece it together. There were some complete bikes on craigslist, but I would end up having to part them out afterwards to recoup some of the csah....that will be a pain.

Keep talking to me guys. Do any of ya'll agree with the racetach guy? Especially on the years of the forks? What about newer KLX forks...are they "better"?
I bought a complete 00 KX 250 to get the forks off. The rest of the bike was a pile but the forks were ok besides needing new seals and what not. I started parting out the bike and have half of my money back already. And I still have the parts that are worth some money to sell. It will take time but you might be able to get paid to swap your forks if your willing to wait.
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