KX fork conversion recap?

Questions and comments about converting to beefier forks..
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KC-10ENG
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Post by KC-10ENG »

Thanks! I am going the complete dual sport route with this bike. I have a 2006 KTM200 for my trail bike.
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Post by heckler »

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Post by jjon456 »

Sorry to be redundant and ask questions already answered but im going crosseyed reading all this.
1) what are the advantages if any of kx 125/250 forks over kx500. as i understand it the kx 500 is just a swap with no machine work ect.
2)would klx 300 forks be a strait swap
I ask because ive found a set of kx 500 forks triple and wheel from brenda at bike bone yard for $175 for the forks/tripple and $75 for the wheel and axle. I dont really have a "shop" right now (more of a leaky shead) and there really arent any good machine shops here so im looking for a bolt on project I can do in a weekend.
Im a nub and have only had my 1996 kdx 200 for a year and its one of the funnest trail bikes ive ever riden so I wanna do all the upgrades this winter while its snowing here in colorado.
Thanks and if anyone is in colorado lets ride! :supz:
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frankenschwinn
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Post by frankenschwinn »

They are all kyb forks using the same technology in any given year. Spring weights will differ to accommodate the heavier 250/500 motor/chassis/riders. 125 motor chassis and riders tend to be lighter so spring rates will be lighter on those. All of them need to be sprung for your weight/riding style and valved accordingly. I don't know about the fitment of the klx300 stem on the KDX frame.
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Indawoods
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Post by Indawoods »

A KX500 frontend is a direct bolt on operation and sounds like your best option.
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Post by jjon456 »

sweet thanks
thats what I was thinking inda
just make sure I had it right before I made the purchase.
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G22inSC
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Post by G22inSC »

With the KX500 direct bolt on option, can you use the KDX wheel/axle or do you still need a complete front end (KX500 fork/tree/wheel/axle)? Trying to research and decide the best route to go.
'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)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
'07 KTM 50SX Sr. (Sold)
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SS109
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Post by SS109 »

You cannot use the KDX wheel and axle. You have to use all KX parts.
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Post by Mr. Wibbens »

>|<>QBB<
SS109 wrote:You cannot use the KDX wheel and axle. You have to use all KX parts.
Why not?
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Post by G22inSC »

>|<>QBB<
SS109 wrote:You cannot use the KDX wheel and axle. You have to use all KX parts.
Thanks. That is what I was thinking; however, I was not positive. Just can't decide...put money towards conversion or new springs and gold valves. I mainly ride mountainous trails but I do occasionally hit tracks with friends just for fun. Just can't get off the fence one way or the other.
'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)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
'07 KTM 50SX Sr. (Sold)
'09 Yam PW50 (retired)
'97 Kaw KX250 (Sold)

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SS109
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Post by SS109 »

>|<>QBB<
Mr. Wibbens wrote:>|<>QBB<Why not?
Because the axles are different between KX and KDX forks. The only way to use the KDX wheel is to machine a custom axle but that isn't a straight swap kind of thing. I also know that the caliper and its bracket are different as well compared to an E series.
Youtube Channel: WildAzzRacing
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Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
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Post by Mr. Wibbens »

So it can be done :wink:
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SS109
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Post by SS109 »

>|<>QBB<
Mr. Wibbens wrote:So it can be done :wink:
:butthead: :mrgreen:
Youtube Channel: WildAzzRacing
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
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2006 KX450F KYB fork (48 mm) to my 2005 KDX 220

Post by heckler »

Thanks to all the people who's helped make this project a reality!

Here's a better drawing of the perfect spacer to fit my 2006 KX450F top crown to my 2005 KDX stem. I'm sure RB does a great job of this, but I've got too much mechanical engineering and a machine shop at my disposal to not do this myself.

No knurling required, although I am making a 30.1 mm ID X 38 mm OD x 1.9 mm thick washer to fit between the lower bearing and the bottom crown. The KDX stem has 1.8 mm of material that has not been ground that sticks out from the lower KX crown and will slightly lengthen the KDX stem fit into the headtube. Not sure if I need it, but my machinist works for cheap.

Image

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I'm currently working on changing the oil to 5WT, and next up with be figuring out how to revalve them for woods for a 180 lb rider. If anyone has any shimstack combos they'd like to share for this, I'm all ears.
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Re: 2006 KX450F KYB fork (48 mm) to my 2005 KDX 220

Post by heckler »

>|<>QBB<
heckler wrote: No knurling required, although I am making a 30.1 mm ID X 38 mm OD x 1.9 mm thick washer to fit between the lower bearing and the bottom crown. The KDX stem has 1.8 mm of material that has not been ground that sticks out from the lower KX crown and will slightly lengthen the KDX stem fit into the headtube. Not sure if I need it, but my machinist works for cheap.
This turned out to be a bad idea. No washer/spacer needed, and now I have to get my brand new lower bearing off to remove the washer. :doh: I don't have enough thread engagement at the upper end of the stem.
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Post by Mr. Wibbens »

bummer

go find someone with a press :wink:
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KDXohio
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KX fork conversion recap?

Post by KDXohio »

Are 89-92 kx 125/250 forks not worth the conversion?

Are they just not much of an improvement over stock?
Or if one could do a rather cheap conversion with them would it be worth while? (By cheap i don't mean cut corners or install junk)

I have a 90 kdx200 I weigh 145lbs I have found an 89-92 250 front end complete for 90$ Piecing together a newer front end is looking like a 300-500$ investment machine work included
So with that being said I have a 1999 kx125 for the track but I'd like my kdx to be track capable as well but mostly going to be woods riding.

Any help is much appreciated be honest I'm new to suspension work so I need all the advise I can get. I'm more than capable of rebuilding, revalving, adjusting....etc but just because someone can do something doesn't mean they know what they are doing.
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: KX fork conversion recap?

Post by Goofaroo »

Are 89-92 kx 125/250 forks not worth the conversion?

Are they just not much of an improvement over stock?
What's wrong with the stock forks?
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Re: KX fork conversion recap?

Post by KDXohio »

Goofaroo wrote:
What's wrong with the stock forks?
They're too soft, I'd like to have the rebound adjust-ability that the USD has and I like that the USD forks stop at the axle so on the trail I don't have to worry about hitting the bottom of the forks on anything. I basically just want the bike to be more track friendly but I dont want to sacrifice woods riding as I have a kx125. I know ill have to mess with the valving of whatever I get to make MX forks woods friendly.
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: KX fork conversion recap?

Post by Goofaroo »

What weight oil are you running in your forks? Fluid level? Stock springs?

There are some basic things you could try before you just give up on the stock forks. They are actually a very nice set-up for woods riding.
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