USD Fork Height

Questions and comments about converting to beefier forks..
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maicocpa
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USD Fork Height

Post by maicocpa »

I have installed a set of 2002 KX 125 forks on my 2006 KDX (a story unto itself) but am concerned with the didtance between axle and bottom of lower triple clamp. With the stock KDX forks this distance was 25.5 inches. With the KX forks it is 27.5 inches in the normal fork position. I have lowered them in the clamps as far as I can and now the distance is 26.5 inches. I know even a 1" difference in fork length can affect handling. How did others of you who have done this conversion deal with this issue?
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jc7622
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Post by jc7622 »

I would try to make the length the same. I raised mine up until they were within a few millimeters of the bottom of the handlebar. At that point they were pretty close to the original dimensions - still a little longer, but as close as I could get. You could always get handlesbar clamps that raise the bars up.

If you raise them up, though, make sure the triple clamp is still clamping on the "clamping portion" of the fork tubes.
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Post by maicocpa »

I already have them as high as the clamping portion will allow so they extend about an inch above the triple clamps. They still sit at one inch longer than the stock KDX forks. I'm going to ride it like that and see if there are noticeable deficiencies in the handling.
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Indawoods
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Post by Indawoods »

Got any pics?

You can't go by your measurements.... because they are just apples and oranges.


See the difference in where the fork clamps and where the bearing sits?

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Post by Dewey »

Mine was also a little taller in the front and I was very skeptical until I rode it some and I actually like it better that way. I have mine set to about 1/4" under the bars. To me it makes the log crossings and such easier, especially on downhills. The KX forks was such an improvement my overall satisfaction is very good. You can probably go with a taller rear tire to help level it out if it is a problem.
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Post by maicocpa »

>|<>QBB<
Indawoods wrote:Got any pics?

You can't go by your measurements.... because they are just apples and oranges.


See the difference in where the fork clamps and where the bearing sits?
I'll post pics when I get the fender, etc. on.

The bottom of the lower KX triple clamp is even lower than the bottom of the KDX clamp (as your picture shows) so the axle to bottom-of-triple clamp distance is even greater. Like I said, I'll ride it and see....
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Post by Green Hornet »

KDX Forks-I measured from the center where the axle would be & measured to the top of the KDX Fork(to where the Cap meets) & its approx. 36 in.
KX Forks measured from the center where the axle would be, I would have to the Top of the KX Forks just about touching the bottom of the Handlebars to come close to 36 in.
Has anyone come up with another figure.
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Post by canyncarvr »

I'm on Inda's side..the numbers don't matter.

What did matter to me was the attitude of the bike. That's why I measured 'level' with the OEM forks, and set the KX forks to exactly the same position. No reason to measure anything. I know the OEM attitude was maintained.

No measurement between the two fork sets is going to allow for sag differences, placement in clamps..none'a that stuff.

But...when it's all said and done, I want the bike to be 'level'. I don't want it going 'uphill'...I don't want it going 'downhill'.

That 'level' setting did put my '99 forks about 1/2" out of the top clamp...and that with a good amount of spacer added under the top clamp. The size of that spacer obviously makes a big difference in handlebar position, and, in the end...what's sticking out of the top clamp.

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Post by Green Hornet »

What was the OEM attitude ???
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Post by canyncarvr »

'Level' as determined using a standard 24" magnesium instrument correspondent to marks made on the seat and tank.

Or...just plain surly.

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Post by knowledge seeker »

I'm almost done with my conversion ('04 KX250F forks to a '06 KDX200) & made the mistake of not measuring "level" the OEM forks to have a reference. Any suggestions on a ball park measurement to begin with?. Any suggestions will be greatly appreciated.

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Post by canyncarvr »

Look at your bike (siting upright on both wheels).

Does it look like it's going uphill? Then it probably is.

Raise the forks in the clamps until it doesn't look that way anymore.

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Post by kawi600 »

Ive got an 06 with 03 KX125 front on it. I ride on really rocky singletrack. Ive had to not only lower the bike as far as possible on the forks (the bottom of the clamping surface) but also use .38 springs. and the bike STILL feels like its hard on the rocks. I get bounced off and damping adjustments dont help. I notice if I place more of my weight than normal over the wheel if feels better so I think its a spring force issue and not damping. When I do this the rear starts to kick out =(
Its taking some time to dial it in, but so far so good.
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