conventional fork rebuild

A service reference
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canyncarvr
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Post by canyncarvr »

Sorry about the 24mm part if that's wrong. I've not taken apart an OEM valve, just seen pictures of 'em. I've READ (I think) that they are 24s. I've not measured them myself.

I don't know they would cover, either...but they must. Not a lot of use in a stack of shims that don't cover the ports. One that doesn't cover as a bleed? OK. Ten of 'em? Doubt it.

The OEM piston don't look anything like a real valve..RaceTech's or anyone elses.

Preload? My imo and all...but the 30-some mm preload in the OEM fork seems just plain stupid to me.

Consider the purpose of the fork is to suspend the bike. Is that going to work better with a spring or with a solid steel tube? I'd say 'spring'. So, I'd remove the steel tube taking up the space!

Preload is as big a personal preference as oil level, viscosity, clicker settings..and everything else on a bike. On my OEM forks (MX-Tech valved), 38kg/mm XR springs, I didn't like 10mm of preload at all. I couldn't turn out of a rut 2" deep on a downhill. The bike would crab..I'd fall down. 3mm? Different bike. No crab. I could choose any track I wanted (uh...no...NOT if the choice was to try turning out of a 16" deep slot).

Another huge improvement (again, imo)? Putting poppers/bleeders on the OEM forks. They built up a LOT of pressure over a days ride. It would build up to a noticeable amount (as reflected in degraded handling) 3-5 times a ride, easy. MotionPro has them..they fit in place of the brass screws in the top cap. Get the tall ones that thread directly INTO the cap. No drill/tap required.

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Post by jimmy97 »

>|<>QBB<
Colorado Mike wrote:I didn't think a 17mm shim would cover the holes in the valve, but then, I never messed with the stock forks/valves other than changing the oil and springs. It sounds to me like your forks were worked on previously by an adventurous soul. How did they act when you rode the bike?

Can you post a pic of the 17mm shim on the face of the valve?
the bike was a wreck when i got it. the forks had been neglected so long there was almost no oil left in either of them , not to mention oil contaminated front brakes ! yeah, this thing was a piece

as far as how they performed, as if i need to explain, choppy/bouncy as hell, did not "float" over anything, i felt it all, And as far as hill climbing goes, that is a joke, front wheel just wanted to bounce up all the time, i struggled on the bigger, root filled ones.... in other words they really sucked !!!

and as far as posting a pic of the stack, not sure how on this forum, i will if somebody will please explain
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Post by canyncarvr »

Pics: Not an option unless you're subscribed, I do believe.

Otherwise, upload to your gallery (or post the pic to a page that allows hot links), then put [img]http://the URL here[/img] in a post here, and up it will show!

If from the gallery, copy the properties of the image (something like this: http://kdxrider.net/forums/modules/albu ... G_0046.jpg ) and paste that URL between the img tags in a post on this forum, it will display IN the post.


Your forks: Not knowing what they will work like when they are setup like they're supposed to be (OEM), changing stuff doesn't make a lot of sense. If you're interested in taking note of what changes what..put 'em back together with a clean oil-fill, ride 'em..THEN make some changes.

How 'bout that?

There is no rebound on the KDX forks, except as determined by oil viscosity. You may well find them pretty bouncy even with oil in 'em.

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Post by jimmy97 »

>|QBB<[/url]
canyncarvr wrote:Pics: Not an option unless you're subscribed, I do believe.

Otherwise, upload to your gallery (or post the pic to a page that allows hot links), then put [img]http://the%20URL%20here[/img] in a post here, and up it will show!

If from the gallery, copy the properties of the image (something like this: http://kdxrider.net/forums/modules/albu ... G_0046.jpg ) and paste that URL between the img tags in a post on this forum, it will display IN the post.


Your forks: Not knowing what they will work like when they are setup like they're supposed to be (OEM), changing stuff doesn't make a lot of sense. If you're interested in taking note of what changes what..put 'em back together with a clean oil-fill, ride 'em..THEN make some changes.

How 'bout that?

There is no rebound on the KDX forks, except as determined by oil viscosity. You may well find them pretty bouncy even with oil in 'em.
i have no idea how to do that, that is upload pics as you described...

but i guess i will just put these bastards back together as is, no changes, ride it, see what i think, money is kinda tight now, but maybe in the future buy new springs, valves, or do the inverted swap!

but thanks to your help i will be able to make changes, if needed, to these forks in the future, thanks again :wink:
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Post by Colorado Mike »

If the largest shim is really 17mm in diameter, I highly recommend you do not put them back together as is. Since you say the stake was already ground off, it's very possible some doofus screwed up the valving for you. You're going to want to work with someone on this site that has a little experience re-valving the stock forks and get at least a few 24mm shims in the stack. Since most folks take out a few of the 24's, maybe a generous soul could mail you some free to get the valves working again. You should open a new thread to get more interest. If you'd like to have the pic posted, Private Message (PM) someone (like me). Subscribing to the site will be a better idea, unless you plan to get rid of your bike soon.
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Post by thebird_19 »

I have mine apart now, waiting to get the rest of my parts to put them back together and mine measure 17mm too. Mine's an 01 and I'm pretty sure no one has been in them because the oil looks stock(swamp mud) and nothing else on the bike seemed to have been changed or upgraded.
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Post by canyncarvr »

Then 17mm it probably is.

You could easily tell if they were supposed to be 24s. The ports in the valve would be exposed I'd guess if 17s were used as face shims where 24s were supposed to go.

I have yet to find where the 24 number first came from. Wrong evidently.

Thanks for the info..the correction.

What the hell do we know, anyway? :roll:

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Post by Colorado Mike »

That's what I get for crossing up memories of KX and KDX fork types. Glad I could "help". :oops:
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Post by canyncarvr »

I thought they were 24s myself..not from taking mine apart. I never did that. I sent'em to MX-Tech long before I'd ever messed with 'em. I was repeating what I thought I'd read from somewhere..but didn't find that post.

See? We all 'helped' on this one! A perfect example of sufficient return on investment, or, you get what you pay for! :wink:

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Post by chris-1742 »

Ride report from someone who just did the shim removal, took maybe fourty-five min. including fork removal/install. I removed 3 of the 10 shims and set the clickers at 8 and road a 35 mile loop of rock, mud (just rained) and hard pack.

Results: TOTALLY different handleing, minimal deflection from larger (6-8") rocks and tracked where pointed in all. BIG IMPROVEMENT and HIGHLY RECOMMENDED for us that still have"stock forks".

If you are considering this mod., 1st. spring for your weight, 2nd, preload with oil change. Do this while everything is apart...it`s easy.

Some hint`s that may help....Compress the fork tube at least 5 inches while removing the base valve with air impact (short bursts). I compressed and held the tube under the work bench while removing the valve, releasing compression once the valve was loose enough to finish with the fingers.(fragile)

Removal of the nut; spend alittle time here filing the "stake" flush to the nut. Once flush, work the nut off (gently)back and forth (1/4 turns) untill off. Working the nut seems to help clean up the threads for the reassembly.

Clean all parts good and replace...I think you will love the difference.
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Post by KDXsg »

really...save the money on the spring for a set of KX front end. right now just go for the min spending on the stock fork like adjusting the spring preload with PVC pipe, higher oil weight and shim mod.

I have spend too much time and effort and money on my stock fork that in the end still go for the kx front end. not worth too much effort on the stock fork. just my thought.
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Post by Indawoods »

You are replying to posts over a year old....
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Post by KDXsg »

Hmmm..so others can learnt from this thread in future? :lol:
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