why not shorten rear linkage?

Questions and comments about converting to beefier forks..
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frenche200
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why not shorten rear linkage?

Post by frenche200 »

Hello! I have read your conversions with KX forks:
From what I've read many of you put spacer in the fork to "shorten" , to not have a bike that looks like a chopper , and problems of handling when you ride...
I wonder why you do not just up the rear with shorten rear linkage?
Not to raise the center of gravity? You have short legs? I'm a 1,84 m rider so i think up the rear of the bike for 2 or 3 centimeters is not a problem..

Thank you :grin:
i'm French and I don't speak English very well, so, please, excuse me :)
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Jaguar
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Re: why not shorten rear linkage?

Post by Jaguar »

since the KDX comes fairly steep angled in the front to handle tight trails well then I would welcome an extended front end to make it handle better at high speed. But you're right in that you can manipulate the rear height with the dog bones. I made my own when I installed an Ohlins shock on it.
Performance CDI -- KDX motocross mods -- the SR KDX -- expansion chamber analysis---> http://www.dragonfly75.com/moto/
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kawagumby
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Re: why not shorten rear linkage?

Post by kawagumby »

You don't need to do any of that to keep the geometry right. Raise the forks in the triples to the right height (exact height depending on rider weight, spring rate, preload, etc) and use bar risers to clear. All you need is the adapters for fat bars to get enough clearance.
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
frenche200
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Re: why not shorten rear linkage?

Post by frenche200 »

Jaguar: thank you for advice! you installed a complete Ohlins shock on E serie? it was made for kdx or another bike?

Kawagumby: fork spring suitable for my weight and was revalved.
I'm not totally agree with you, but I'm not an expert, I could be wrong .. :hmm: (but maybe I misunderstood what you wrote )
The outer tube of the fork KX is a variable diameter so can not be raise a lot ..
By measuring the distance between the front axle and lower triple with my fork USD original (it's an E5), and if compared with the measurements of KX fork maximum raise, there still a significant difference that I find visually ugly (unbalanced machine) and which, in my opinion, must feel at handling (sensations of front heavy...)
i'm French and I don't speak English very well, so, please, excuse me :)
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kawagumby
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Re: why not shorten rear linkage?

Post by kawagumby »

My experience includes 3 USD installations on H models and 1 on a 1987 C model KDX. I've never done an E model but think you will still get plenty of contact area at the upper triple clamps when raising the forks slightly more than one inch (nearly up to 1-1/4 inch on my bikes) to get the correct ride geometry. I am using Yamaha forks, but I think the outer housing (KYB) is the same for KX forks. On my C model the upper clamp only contacts about one inch where the forks are widest, but I have never had the forks come loose or distort, and I jump fairly large jumps with it and ride it pretty hard in rough terrain. You might want to try raising them the full amount and see if any problems arise before you commit to another solution...just a suggestion. :boogie:

Here's a link to the fork conversion on my C model which has the highest placed forks of all four bikes I put USD's on. I've been riding it for over a year and have had no problems... and I push my bikes pretty hard in rough terrain...
http://www.kdxrider.net/forums/viewtopi ... 19&t=12349
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
frenche200
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Re: why not shorten rear linkage?

Post by frenche200 »

Your C is a a very very nice bike :bravo:
And i see how your fork is (very!) up in the triple... :wink: I also hesitate to increase the ground clearance for crossing, but I told myself that it may endicaper me when to "pedaling" on the ground to start in mounted for example ...
I think initially follow your advice and ride , and see! After if it's not good i 'll home made some rear linkage!
Thank you for your knowledge sharing :grin:
i'm French and I don't speak English very well, so, please, excuse me :)
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Jaguar
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Re: why not shorten rear linkage?

Post by Jaguar »

yes frenche, I put an Ohlins shock from a KTM enduro bike on my '89 KDX200 and loved it. If any one thinks the stock shock is OK its just because they've never had an Ohlins which has much less stiction. Of course I had to revalve the shock for my motocross use but if I was just woods riding then it would of been fine as is. I also had to make longer dog bones because this Ohlins was longer. An Ohlins from a GasGas EC is 20mm longer than the KDX shock. here's what someone else had to say about swapping for an Ohlins:
"I fitted a GasGas ec250 rear Ohlins to my 90 KDX. Mounts were the same size, the shock was 20mm longer. I made my own lowering links to compensate. It was a pre 2000 Ohlins. Made a big difference to my riding and looks sweet."
Performance CDI -- KDX motocross mods -- the SR KDX -- expansion chamber analysis---> http://www.dragonfly75.com/moto/
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