Conversion measurements?

Questions and comments about converting to beefier forks..
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G22inSC
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Conversion measurements?

Post by G22inSC »

I have all my parts and am fixing to send the trees/stems to RB for the machine work and swap. I am wondering about the dimensions on the current front end. What is the best way everyone has found to take a measurement that you could duplicate with the KX forks to achieve the same bike geometry?

I was thinking of something along the lines of a measurement between the center line of the axle and lower surface of the frame head stay.

Both the trees and forks are shaped and sized differently so I want to make sure I can get the same "numbers" on the conversion. What did you'll do?
'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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2005 KDX200 Bike Profile
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rbates9
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Post by rbates9 »

I rested the bike on both wheels in a neutral un loaded position and measured from the floor to the head tube and made a mark with a marker, wrote down the measurement and when I was done did the same thing. I ended up with about 1/8" taller with the KX forks. Looking back on it I probably should have had some one else measure it while I was sitting on it but it wasn't that important to me just a curiosity thing.
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frankenschwinn
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Post by frankenschwinn »

Measure axle to top of lower triple or bottom of head tube. In mtn biking its called the axle to crown measurement.
chopper
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Post by chopper »

Most accurate way is to measure inside the bottom triple clamp against the bottom of the steering stem down to the axle with the wheel removed. You will then need to measure the distance from the bottom of the stem to the lower bearing unless that measurement is the same on both lower clamps. In that case, the stem to axle distance would be all that you need to know.
ditton
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Post by ditton »

Hi all...
Just wondering this as I am now in the process of doing the conversion on an 03 220 using 03 kx125 forks.
However, I thought about measuring on the forks(before after) but decided against that as thought the forks/clamps lengths, thickness', etc are different therefore.....could be wrong but it made sense to me at the time.
What I did was take a couple of measurements (with KDX forks) to a couple of different locations on bike, bike was level up/down. Measured to a mark on side panel, frame bottom(at foot peg), swingarm.
When KX forks go back in, I will reproduce the same measurements at all locations by moving KX forks up/down in clamps.
KDX felt like it was right for me, that is why I used those measurements
Sounded good to the little voices in my head at the time......
Yes, I had help to make measurements (hold bike straight) and will need help to reproduce........thats all he wanted to do....hold bike....to much thinking for him!!!! or too many beers!

Ditton
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G22inSC
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Post by G22inSC »

>|<>QBB<
frankenschwinn wrote:Measure axle to top of lower triple or bottom of head tube. In mtn biking its called the axle to crown measurement.
Thanks. That is what I was thinking without knowing it had an actual term. I greatly appreciate it. Now if I can get my parts back and out from under a head cold I will be on my way.
'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)

Gallery

2005 KDX200 Bike Profile
ditton
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Post by ditton »

G22inSC wrote:>|<>QBB<
frankenschwinn wrote:Measure axle to top of lower triple or bottom of head tube. In mtn biking its called the axle to crown measurement.
Thanks. That is what I was thinking without knowing it had an actual term. I greatly appreciate it. Now if I can get my parts back and out from under a head cold I will be on my way.
frankenschwinn wrote:
Measure axle to top of lower triple or bottom of head tube. In mtn biking its called the axle to crown measurement.

Or...with KX fork beside KDX fork (both slightly pulled to ensure at full length) and the tops of forks even, measure the distance from the centre of the KX axle (would be) to the centre of the KDX axle(would be). This measurement should be put above the top triple clamp.
This is due do on my bike the KDX fork is even with the top of the triple clamp.
However, with mine I'm sure there will be some farting around tweeking these measurements to see what feels best. I like the way bike felt before the conversion and want to try and keep it as such. Front forks will change alot of things if these measurements are way off. I am using my frame measurements as there seems to be too many variables when making measurements at forks, etc....forks are different lengths, Triple clamps are not the same thickness'.......so measurements at the frame seem less variables.

Thats just me....could be overthinking.....its just those voices inside my head.....

Ditton
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rbates9
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Post by rbates9 »

Probably should get some measurements with you sitting on the bike also due to the amount the different forks will settle with weight on them. Kinda like the sag on the rear shock.
ditton
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Post by ditton »

Good point Rbates9.......never thought of that......or at least the "little voices upstairs" didn't. Makes sense, coz I have done rear sag setting when I got it and plan on doing it again after servicing the rear
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