H series kdx with 03 kx250 forks lowering question

[JZ05220r]

I have an H series kdx with kx forks. I am having the suspension revalved and resprung this winter. I noticed the kx forks need to be raised up on the triple clamps a good amount to get close to the stock geometry. I was wondering if anyone knows how short I should have the forks internally lowered in order to get close to stock geometry without having the top caps on the forks nearly touching the handlebars. Are there any suspension shops that you guys recommend that have fair prices and do good work? Thank you.

[bufftester]

I would think you would lower it internally the same distance that you would raise them if you didn't go the internal route, 1.e.: if you have them up 25mm in the clamps, lowering them internally 25mm and running the caps at the top of the triple clamps should be the same

[JZ05220r]

I would think you would lower it internally the same distance that you would raise them if you didn't go the internal route, 1.e.: if you have them up 25mm in the clamps, lowering them internally 25mm and running the caps at the top of the triple clamps should be the same

Your logic is probably more realistic than mine. I just wanted to see if their is a way to figure out exactly the different lengths between the stock and kx.

[bufftester]

Measure from center of the front axle to the top of the triple clamp on the KDX forks, then raise the replacement fork until you get the same measurement. However much sticks above the triple clamp is the amount you need.

[JZ05220r]

Measure from center of the front axle to the top of the triple clamp on the KDX forks, then raise the replacement fork until you get the same measurement. However much sticks above the triple clamp is the amount you need.

Gotcha, i do not have the stock forks anymore. Also if I did still have them, the stock lower triple actually is shaped different (the fork tube clamps on lower triple are higher up in relation to where the steering stem is pressed in) than the kx lower triple. So if I measured to the bottom clamps then the measurements would be inaccurate.

[KDXGarage]

Measure to the top of the head tube maybe??

I would want 5 - 10mm of room to have them up a little as an option. I think the 2004 KX125 had the tubes 15 mm above the clamps as far as Team Green notes.

[JZ05220r]

Measure to the top of the head tube maybe??

I would want 5 - 10mm of room to have them up a little as an option. I think the 2004 KX125 had the tubes 15 mm above the clamps as far as Team Green notes.

Right, what I don’t want is lower the forks internally too short. Where I have it set minus 5-10mm to play around with is probably the number I’m looking for, I agree

[KDXGarage]

I think stock was 5 mm above, then Team Green suggested 15 mm, something like that on the 2004 KX125. (a mere 20 years ago, JEEZ)

[John_S]

I had my USD forks done recently (gold valves and dyno tuned) and asked him about the difference in heights. He had me measure my stock forks from the axle center line to the top of the dust seal, then from the top of the dust seal to the bottom of the upper fork cap in MM's. With those 2 measurements and my 2000 KX 250 forks in hand he did the internal shortening. He ended up with a whole page of math that I hardly understood with travel, stock set heights above the clamps, preload, spring heights etc for both bikes in stock form. He set mine at 10 mm above the clamps as a starting point and said if you feel it knifing in the sand or feels twitchy at high speed to try 5mm above. I rode yesterday (scary tight and deep sugar sand trails) and I'm going to raise the front end the 5mm. The faster you go the more you notice how good the forks are now.

[JZ05220r]

I had my USD forks done recently (gold valves and dyno tuned) and asked him about the difference in heights. He had me measure my stock forks from the axle center line to the top of the dust seal, then from the top of the dust seal to the bottom of the upper fork cap in MM's. With those 2 measurements and my 2000 KX 250 forks in hand he did the internal shortening. He ended up with a whole page of math that I hardly understood with travel, stock set heights above the clamps, preload, spring heights etc for both bikes in stock form. He set mine at 10 mm above the clamps as a starting point and said if you feel it knifing in the sand or feels twitchy at high speed to try 5mm above. I rode yesterday (scary tight and deep sugar sand trails) and I'm going to raise the front end the 5mm. The faster you go the more you notice how good the forks are now.

Who did you have do your suspension? Did you have to perform those measurements on both the stock forks/t clamps and the kx forks/t clamps? I know Ron puts a spacer below the kx top clamp. Thanks

[John_S]

Tom Fleming of TF Suspension. I saw his stickers on a lot of the GNCC guys bikes. I looked them up and they're 10 minutes from my house and he's in his 50th year of business so I figured I better get my bike done before he decides to retire like RB.

He said he has suspension sent to him from Washington to New York and everywhere in between in those plastic rifle cases with the foam inside. If you're interested I would check out their website and email them for lead times. Him and his wife Ellen are really amazing and travel around with their rig servicing bikes at various GNCC's and 24 hour races plus their grandson is an A woods rider so they go to his races also.
He has the kind of shop and knowledge that would make you want to stay there all day talking to him. I took him the whole bike and had him do the front and rear.

As far as my bike goes...I had RB do the steering stem swap, the bushing, and the axle mod a few years ago. So when TF got my bike the only measurements I could give him (and that he wanted) was the ones I mentioned of the stock forks. When I first did the swap a few years ago, I measured the stock KDX suspension from the axle center line to the bottom of the steering tube and put the KX forks the same which had them about 15mm up out of the top triple clamp.

[JZ05220r]

Tom Fleming of TF Suspension. I saw his stickers on a lot of the GNCC guys bikes. I looked them up and they're 10 minutes from my house and he's in his 50th year of business so I figured I better get my bike done before he decides to retire like RB.

He said he has suspension sent to him from Washington to New York and everywhere in between in those plastic rifle cases with the foam inside. If you're interested I would check out their website and email them for lead times. Him and his wife Ellen are really amazing and travel around with their rig servicing bikes at various GNCC's and 24 hour races plus their grandson is an A woods rider so they go to his races also.
He has the kind of shop and knowledge that would make you want to stay there all day talking to him. I took him the whole bike and had him do the front and rear.

As far as my bike goes...I had RB do the steering stem swap, the bushing, and the axle mod a few years ago. So when TF got my bike the only measurements I could give him (and that he wanted) was the ones I mentioned of the stock forks. When I first did the swap a few years ago, I measured the stock KDX suspension from the axle center line to the bottom of the steering tube and put the KX forks the same which had them about 15mm up out of the top triple clamp.

Thanks for the info. I checked out their site. I’ll probably give them a call when the time comes and see what they recommend based on my situation/me not having the stock forks and measurements to go off of.