KDXRIDER.NET

Ok. I have tore one of the forks down as per the manual and other aquired reading. My bike is a 1993 200. What is the factory preload? How do I change it (what do I remove or replace?)? I don't know what makes up the factory preload. What I mean is I don't see anything replaceable. I have my new Freddett .40 springs and my PVC. I am thinking 6 or 8 mm but any other ideas would be great.

Which shim do I remove? I have heard one is enough. The one on the bottom of the stack is different (outside diameter-same, inside diameter bigger)

The forks look as though they have been into before and the oil in them looked like grey water. NICE

Thanks Guys
Vinny

Your bike still has the OEM USD forks?

Most of the questions you are asking (spacers, changing preload) have to do with the cartridge forks used on the 'H' type where the spacer is a steel tube around 90mm or so long.

USD forks don't work that way. You can add preload to the existing setup (above the 44028A guide), but the spring/assembly generally takes up the space there is.

How much preload do you have? I don't know. Figure it out. You can measure how far the rod sticks out of the spring without the cap on, subtract from the the depth the rod threads into the cap. You can vary the placement of the 95015A nut, although that is generally locked against the cap after it is threaded ALL the way onto the rod.

Which shim?

Generally you would remove shims that are against the face of the piston. When you say 'bottom of the stack' I wouldn't bet WHICH way you're referring to. The stack is basically a tapered stack. The largest outside diameter is the one you're looking to remove.

Keep in mind all of this is related to the commonly held 'good deal' in removing some of the multiple shims of the same diameter in the 'H' model..not your bike.

IF you have (example) six 24mm shims, take out two. See how you like it. If there are not multiple shims of a large diameter stacked against the piston of your base valve (say, if there is only one or two) I wouldn't remove any. I'd also wonder who took them out/off already.

Never remove a shim that will leave the stack configured in such a way that the ports (holes) in the piston are not covered.

6-8mm preload is fine..but, again...you don't have the choices in preload to make on the USD fork that you do on the RSU conventional fork.

Yes they are factory usd forks. I have new .40 Fredette springs and the pvc. I am replacing the bushings, seals and oil. As far as the shim stack goes all the shims have the same outside diameter best I can tell. When I say bottom I mean bottom from a usd point of view. I guess that would mean top on a conventional set of forks concidering I assume the valve is on top of the forks.

I have hunted for info a good bit about this subject but I would say 98% is based around KX and conventional forks. I need to here from someone that has done what I am trying to do.

Vinny

The KX USD fork is similar to yours in regard to your questions: Preload and base valve stack configuration. You don't need specific info in regard to your particular year of fork.

The bottom of the stack has components that only take up space on the stud to allow the attaching nut to hold the actual valving components.

Everything said earlier (preload, jam nut position, BV stack configuration) applies whether the subject is your '93KDX200 or my '99KX250 setup.

vinny wrote:Yes they are factory usd forks. I have new .40 Fredette springs and the pvc.

Did you not read any of Brad's post above?

I'm sorry, WHO is Brad?

Brad is CanynCarvr.

Did you buy springs to suit USD KDX forks or conventional KDX forks ??

You use the PVC as a spacer on CONVENTIONALS not USD forks.

Clear as mud ?!?

The springs Fredette offers are for 89-06 by the listing on his website. guessing they include conventional and USD. Why was I supposed to know him by his first name?

Are there anymore obvious things I apperantly don't know that I need too know about servicing the forks?

I appreciate all the info I recieve on this site from everyone but some have been doing this alot longer and apparently some have not much more to do but try to make others feel ignorant

So vinny, don't get upset now! Typing isn't the quickest and most efficient method of communication. And the lack of details flows both ways. Who out there would have known from your original post that you had the only year they made the USD forks for a KDX for example? Not me. But Brad did. AKA Carver, Canyncarvr, CC, and a host of other names we all get to call him when we meet him in person and break out the beers.

And if Wibby made you feel ignorant, then you don't know Wib! Read his sig line. It's an instruction manual for how to take his sense of humor.

BTW, I'm Jerry. I mention that because if you hang around here for any length of time, you might wanna call me by my first name instead of my on-line moniker.

It sounds like Fredette either didn't pay close attention when you told him what you needed in the way of springs, or you didn't tell him at all and took the info from just his listing. I recommend you give Jeff a call. He will talk to you! Amazing in this day and age, that a regular joe, or, vinny in your case, can just pick up a phone and talk to a world renowned racer about your forks. His mom usually answers the phone, so say hi to her and ask if Jeff can come to the phone.

Keep asking questions and for gosh sakes, don't feel ignorant any longer than you have to! We are here to help!! (No, I'm not from the government either!) HaW!!

Well, I try to be very patient. I figured that if didnt post this in the KX conversion forum it would be a no brainer that my forks are factory usd. I did state it was a 1993 (and by the way 94s are usd too)

All I have heard about is preload, shims, PRELOAD, shims, etc.

Brad said to be less ignorant. When I don't know something I ask QUESTIONS and read. I do a lot of reading. When I ask here its because I don't know and I may not be able to find nothing but contridiction using the search. I have noticed that alot of people here assume everyone knows there first name and what kind of bike they have. I don't assume this thats why I usually say at least what year my bike is.

By the way my name is Vince. Nice to meet you Jerry!

vinny wrote:I'm sorry, WHO is Brad?

Sorry my bad, since at the time only one other person had posted to this thread other than yourself, I figgerd you woulda figgerd WHO it was

Hey Vince, I'm Dr Trev... I think you need a warm mug of 'calm the fark down'. No offence intended at all.

vinny wrote:Brad said to be less ignorant.

I musta missed that part. Theres no need to get all huffy buddy, if theres something thats not clear just ask. We are only trying to help. Alot of the time for me anyway, Brad/CC is kinda like the riddler. I'll re-read what he has said about 10x and I'm still mostly confused BUT all it takes is a few questions and he is usually more than happy to clear up any confusion. Good luck and hope ya get your forks all sorted with minimal headaches...

Cheers,
Trev...

Vinny,
Any spring 35.8x472mm will work in your bike according to Race-Tech's site (which is the same as any KDX). Please give us a measurement of your stock springs.....

Rate is dependent on your weight but the stock rate is .30!

Sounds a tad weak for anybody....

I have a few sets of springs out in my cold @ss garage and I will measure them for ya....

Well I have new springs already. .40 springs from Fredette. Both the old spring and the new spring measure 474.5 mm laying flat. Basicly allI wanted to do was to install new bushings and seals along with heavier springs and new oil. I have read alot about preload but nowhere have I read that is mostly to do with conventional forks and not usd forks. Ya know its hard to read ALL the info about everything.

Here is the rundown. I am going to do the things above. Plus remove one shim from the shim stack. Best I know that is the only easy fast mods to do. Thanks for eveyones help. Even yours CC.

Vinny