fork questions

bart · Post by **bart** » 07:18 am Feb 16 2012

Hi, everyone I just bought my first dirty bike, 96 kdx 200, for cheap. My dad is an experienced bike tech so I have good help. I've done some research and am interested in the KX fork swap. Partly because I suspect a fork may be cracked (!) as there's a good amount of hardened epoxy around the bottom. Here's a picture: http://i234.photobucket.com/albums/ee24 ... AG0292.jpg

Do forks normally get cracked there? I didn't find much info about this.

So I found on craigslist, 97 kx250 parting out. I can get the whole front end for $180. Send the triple clamp to RB no prob. It's also nice because my dad said the front wheel might be a little bent.. My questions are some things I haven't found or are vague to me, and I could use some further (layman) explanation.

Firstly, my intentions are to build a woods bike that can do single trail extreme technical stuff as well as tear up the 2 lane. I weigh 145lbs with gear. I've already done some technical single trail and it was a bit rough. The front end lifted a lot and didn't seem to firmly plant. Roots and rocks were pretty jarring and made handling difficult... but I don't have much of a baseline. Could that be the forks/valving?

Mid-valve on the 97 kx 200 is likely, I read here: http://kdxrider.net/Kayaba.htm . And I did some more reading about what the mid-valve does. It isn't desirable for me.

First question: Is it no problem to replace the mid-valve on KX forks when installing the gold valve kit?

Reading here, gold valves seem to be recommended for someone as light weight as me. I gotta get rid of that mid-valve though!(?) So hoping someone can chime in about replacing it on the kx forks with the gold valve kit from Race Tech. I did some reading about this and found some mixed opinions.

Second question: Are the KX forks going to make the bike taller? And will revalving/respringing lower the bike for my weight, to normal height? After setting the race sag.

Third question: How do I balance out the bike with KX forks, front/rear? I know you gotta adjust the triple clamp as the KX forks are longer. So what do I have to adjust in the rear to balance things out? I know front/rear balance on a bike is important, as far as even weight distribution. Planning to consult a suspension shop about the front/rear revalving and re-springing.

I'll probably have more fork-related questions. Thanks

turtle · Post by **turtle** » 09:09 am Feb 16 2012

Welcome Bart! Lots of great questions, many of which I have myself. So ....

Tedh98 · Post by **Tedh98** » 06:19 pm Feb 16 2012

There is a lot of info out there on revalving those forks for woods.

You don't need gold valves. And you especially don't need to turn the mid valve into a checkplate.

You just need to tune the mid valve for your type of riding. By keping it you wind up with a better set of forks.

You may be able to slide the KX forks high enough to work. But you need to double check that the tire can't hit the underside of the fender when they bottom. The forks can be shortened through the use of spacers or cutting internal components. You will either need shorter springs or have the spring perches raised.

bart · Post by **bart** » 11:40 pm Feb 17 2012

Thanks that info helps a lot. I'll talk to the suspension guy about shortening the forks. They want $460 to fully revalve the front and 430 for the rear. Seems a bit pricey, without springs too. I'll do some research. Would I be able to get away with just revalving the kx forks and just changing out the rear spring (for my weight)?

Tedh98 · Post by **Tedh98** » 01:42 pm Feb 18 2012

bart wrote:They want $460 to fully revalve the front and 430 for the rear. Seems a bit pricey, without springs too.

Wow, that is a lot. I hope that includes new oil, bushings, seals etc. If that is the cost for just changing out shims, I'd find another place.

But doing it your self isn't that difficult.

I've ready many experienced suspension people say that springs should be the first thing on the list.

Post by **SS109** » 11:34 pm Feb 18 2012

bart wrote:They want $460 to fully revalve the front and 430 for the rear.

Talk to Donny at ZR1. (http://www.zr1suspension.com/services_dirt.php). I bet he will get you done with springs way cheaper than that. He revalved and rebuilt my forks and did a rebuild on my shock for right at $220.

bart · Post by **bart** » 04:43 am Feb 19 2012

Are the KX500 forks also longer than the stock KDX200 forks? Would be nice if I could just do springs, service & seals, and save the revalving for later.

That's quite a deal at ZR1. I'll check it out, thanks. That original quote does include valves, bushings, seals and oil. $120 front/$80 rear for labor. I wonder how much they're marking up parts, they say its costing 300 per end just in parts.

If I did maybe want to crack into this revalve/rebuild myself, where could I find the kit/parts? Thanks!

factoryX · Post by **factoryX** » 04:46 am Feb 19 2012

http://racetech.com/

http://racetech.com/VehicleSearch

Tedh98 · Post by **Tedh98** » 08:23 am Feb 19 2012

bart wrote:If I did maybe want to crack into this revalve/rebuild myself, where could I find the kit/parts? Thanks!

Pivotworks rebuild kits are cheaper, but I've read mixed reviews on quality, longevity of seals and parts not fitting properly. Just received an OEM KYB bushing/seal kit from eBay for a good price.

http://www.suspensiondirect.com/ has good prices and shipped fast.

heckler · Post by **heckler** » 10:29 pm Feb 19 2012

make sure you get the right weight of fork springs long before you pay anyone to revalve a fork.

bart · Post by **bart** » 06:47 am Feb 24 2012

heckler wrote:make sure you get the right weight of fork springs long before you pay anyone to revalve a fork.

Yeah, you're right.

The 1997 kx250 fork springs match my weight well enough (145lb w/ gear) at .40kg/mm. In 2000 they were changed to .43kg/mm, as well as other (mostly mx) performance revisions.

A guy at work pointed out the under hang of the kdx forks vs. the KX250. Here's a thread about it: http://www.dirtrider.net/forums3/showth ... adid=96120
The long under hang would appear to be detrimental, as my KDX fork is cracked (and epoxyed) at the under hang. I'm wondering why they never upgraded the forks even on the newer KDX.

Anyway, I'm excited to pick up the KX250 front end this weekend. I found a local guy parting out a '97. He wants just $100 for the forks and triple but $80 for the front wheel! He also said the tire on it needs to be replaced. So I'll see if he'll throw anything else in. Maybe grab the caliper and master cyl. just to be safe with the swap. And anything else he'll give me free!

I also found these guys at moto-pro are a great resource: http://www.moto-pro.com/mybike.asp

KDXRIDER.NET

KDXRIDER.NET

fork questions

fork questions