Suspesnion upgrade vs KX

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KawE30
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Suspesnion upgrade vs KX

Post by KawE30 »

Have had my 2002 kdx200 for a couple months, started riding offroad with it and it's been great. Love the motor.

Yet I can't help but notice how violently the bike tries to throw me off when riding at an MX pace. Hopping on a 125 riding through tight wood trails, small sand dunes, and motocross-like forest and sand sections is much, much faster and easier on my friends 2003 rm125, due to suspension alone.

Which left me thinking - will revalving or rebuilding forks and replacing spring make a noticeable difference in those types of riding situations , or am I just better off selling the good ole kdx for a MX bike or KTM enduro?
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bufftester
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Re: Suspesnion upgrade vs KX

Post by bufftester »

The biggest and most important work you can do on your bike is to set the suspension up properly. From the factory the KDX is soft in front and stiff in back, making for some uncomfortable riding at race speeds. Get it sprung for your riding weight (not your I think I used to weigh this, but your actual get on a scale, silently scream OMG WTF is wrong with this scale weight) and have the sag set correctly. Don't bother with valving or shim mods or anything, just respring and ride. Then wipe the smile off your face and look at revalving.
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Re: Suspesnion upgrade vs KX

Post by KDXGarage »

You said you have had it for a couple of months. Let me be bold and guess. You have not done JACK to the suspension. Correct?
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Suspesnion upgrade vs KX

Post by SS109 »

I will go against most and say the stock forks suck IMO. They're just not worth investing the money in unless you plan on doing casual trail riding or really slow speed technical riding where they can actually be pretty good. They are old technology (as in 1980's tech), flex way too much, and have no rebound control so that = sucks IMO. Well, for any spirited riding over rough ground that is and, the rougher and faster it gets, the worse they get. There's a reason we have a fork conversion sub-forum. Just about any fork from about '96 and up would be a nice upgrade with modern closed/dual chamber forks being the best.

That being said, I would at least try to dial in what you already have. That way you will actually know if the better forks would be worth it for you. Set your sag, if needed find some cheap used springs, and see how it goes.
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Re: Suspesnion upgrade vs KX

Post by KDXGarage »

Proper maintenance and setup will not make forks designed to meet a certain price point equal to forks that were for a bike with a significantly higher price tag. KDX forks are great for the price the original owner paid. If you want high level performance from forks, buy and install high performance level forks. :grin:
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KawE30
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Suspesnion upgrade vs KX

Post by KawE30 »

Before doing anything I'm adjusting the sag. And about to order Race Tech .42 front fork springs. Then gonna install them, I feel like it will be a huge improvement. If i feel like it's still lackluster I will think about revalve or bike upgrade and report to you guys

I'm 178 lb without gear. Does .42 front fork springs sound about right for the front ? For the fast enduro and a little motocross?

I'm also confused about the rear. Race Tech calculator says to buy like 5.3 , but I heard that even the 5.0 stock springs are a bit much for someone my weight. A kdx motocross suspension guide said to get 4.7 for my weight.

I was just gonna leave the stock ones, should the handling be alright? Coupled with the .42 racetechs
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Re: Suspesnion upgrade vs KX

Post by KawE30 »

bufftester wrote:The biggest and most important work you can do on your bike is to set the suspension up properly. From the factory the KDX is soft in front and stiff in back, making for some uncomfortable riding at race speeds. Get it sprung for your riding weight (not your I think I used to weigh this, but your actual get on a scale, silently scream OMG WTF is wrong with this scale weight) and have the sag set correctly. Don't bother with valving or shim mods or anything, just respring and ride. Then wipe the smile off your face and look at revalving.
I will do as you suggest, sounds like it will help a lot as I haven't done anything to the suspension at all.

I'm 178 lbs, can you recommend spring rates front and rear for my type of riding ?4.2 front im confident about but confused on rear.
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Re: Suspesnion upgrade vs KX

Post by bufftester »

Stock rear is a 5.0, stock fronts are .35

Use the racetech calculator and plug in your numbers. I did some internet estimation on the information not provided and came up with ....tada!
ENDURO.............................................MOTOCROSS

Riding Type: Enduro............................. Riding Type: Motocross
Age: Standard Age - Up to 29...................Age: Standard Age - Up to 29
Skill Level: Intermediate/B Class...............Skill Level: Intermediate/B Class
Height: Standard Height........................Height: Standard Height
Gas Tank: Standard Gas Tank..................Gas Tank: Standard Gas Tank
FRONT FORK SPRINGS Recommended Fork Spring Rate: (use closest available)
0.399 kg/mm .....................................0.424 kg/mm
REAR SHOCK SPRINGS Recommended Spring Rate: (use closest available)
5.23 kg/mm.......................................5.33 kg/mm

based on that IIWM I'd probably go .42 front 5.2 rear and call it a day. BUt you have to decide what kind of riding you want to set it for. Keep in mind that suspension for the track is going to be stiffer than the woods, and the KDX frame kinda sucks on the track. At your weight you could probably leave the stock rear on to start with and see if the change in the front helps at all. As mentioned above, there's a reason we have a fork mod subforum! And also I have a Hybrid so my personal view is also slanted :wink:
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