conventional fork rebuild

A service reference
jimmy97
Member
Posts: 35
Joined: 03:20 am Apr 04 2009
Country:

conventional fork rebuild

Post by jimmy97 »

hello all, new to this sight
i own a 1997 kdx 200 and am replacing the fork seals, these are conventional forks, i am not a stranger to working on motorcycles by any means, but i have never worked on forks, and for the life of me, i can not get the tubes seperated. i have the first retaining ring off and the dust seal removed, this is where i am stuck, when i pull the tubes as far as they can go i see 2 holes and thats as far as they go, do i need special tools, or am i just overlooking something, any advice would be greatly appreciated
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Yank 'em Crank 'em.... they will come apart! :wink:
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
jimmy97
Member
Posts: 35
Joined: 03:20 am Apr 04 2009
Country:

Post by jimmy97 »

so the seals will just pull right out if you pull the tubes apart??? guess i wasn't pullin hard enough :?
jimmy97
Member
Posts: 35
Joined: 03:20 am Apr 04 2009
Country:

Post by jimmy97 »

ok got the seals and a small brass bushing out, but the tubes will STILL not seperate... what the heck am i doing wrong ?
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

>|<>QBB<
jimmy97 wrote:so the seals will just pull right out if you pull the tubes apart??? guess i wasn't pullin hard enough :?
You don't 'pull'. You use the inner like a slide hammer...not with a SLAM SLAM SLAM...but a tap tap tap tap....

They are supposed to come apart fairly easily. Mine didn't. I tried it the tap tap method..graduated to the SLAM SLAM SLAM method 'cuz that's what was needed to get the tubes apart.

And..in the process, ruined both the inner and outer bushings. That was fine, 'cuz I was taking them apart to replace them (and the seals) anyway.

BTW..this assumes you have the cartridge OUT. You do..right?

No...not absolutely necessary..but to do it otherwise doesn't make any sense. The base valve comes out, the cartridge out..THEN the slide-hammer effect.

So...what's the update? This thread is pretty old..and surely has more to it than was true three weeks ago..

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
jimmy97
Member
Posts: 35
Joined: 03:20 am Apr 04 2009
Country:

Post by jimmy97 »

no, the forks are still not fully apart :cry: the tubes are still together, seals are out though. also need new bushings..... does the hex socket nut on the bottom come out ? if so i CAN NOT get it out.... there is a reason i never work on forks :evil:
User avatar
Colorado Mike
Gold Member
Gold Member
Posts: 1921
Joined: 11:42 am Feb 25 2005
Country:
Location: Colorado

Post by Colorado Mike »

Yeah it comes out. That's the base valve. An air wrench buzzes them out easy.
Mike

Life's tough, it's even tougher if you're stupid.
'04 KDX220
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

Uh oh....

'ya see...that's what comes from assuming things.......

Sorry...'i am not a stranger to working on motorcycles by any means,' lulled me into an unusual state of not harping on the painfully obvious. Harping generally leads to people getting pi$$ed.

As CM says...the base valve has to come out. It should have come out FIRST!!!

That base valve is screwed into the cartridge.

They can be tough to get out. IF you get them to move, they will often just spin..you are spinning the whole cartridge INSide the fork tube.

You don't want to do that.

Reassemble your fork to the extent of having the spring back on the rod with the spacers that came out of it. You don't need to put oil in it.

Ensure the base valve is free to come OUT of the fork tube. If the metal of the tube is beat to occlude the removal path of the valve..use the proper tool to remove/reshape that fork metal. You want the BV to have a clear shot at coming out.

Turn the fork upside down and while compressing the fork (puts pressure on the cartridge against the outer fork tube so the cart will less likely spin), hit the base valve with an impact (it's a 14mm hex). Do not exert a lot of pressure on the valve itself..the threads are very fine..you can lean on them enough to mess them up (if they aren't toast already from banging on 'em).

There's a correct way to use an impact in such a situation...I'll assume you know what that is. Just 'pop' it out..no extended drive, NO huge downward pressure. IF it spins, get someone to give you a hand compressing the fork to add pressure.


BTW...I said earlier, 'BTW..this assumes you have the cartridge OUT. You do..right?'

THAT was asking if you had the cartridge out...which means the base valve would have been removed.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
jimmy97
Member
Posts: 35
Joined: 03:20 am Apr 04 2009
Country:

Post by jimmy97 »

cool, i'll give that a shot here in a couple of days.... i'll keep ya posted on the outcome..... wish mu luck :?
riggy
Member
Posts: 46
Joined: 01:24 pm Mar 14 2009
Country:

Post by riggy »

keep us posted I am getting ready to do mine , and converting my forks to kx forks will be intresting I am sure . never messed with forks till know .. i MAY BE :rolleyes: WHEN FINISHED .
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

Most riders that have taken out a handful of the face shims in the base valve figure it to be a big improvement. Far more helpful if sprung for your weight..but there are something like 10-12 24's in there. Take out 5-6 of 'em.

*note* Should be obvious..but ftr..do remove the stake before trying to remove the nut. Ruin that valve and you're not going to be happy.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
jimmy97
Member
Posts: 35
Joined: 03:20 am Apr 04 2009
Country:

Post by jimmy97 »

FILALLY ! ! ! got these bastards apart ! and YES you do need a buddy ! while they are apart, any suggestions on what should be replaced, while apart ? (i plan on owning this bike for a while) i have already bought fork dust / oil seals, and the large metal teflon coated bushings that go below the oil seals and the slightly bigger metal teflon coated bushings that clips on the bottom of the inner tube (the one that clamps to the trip tree) ? any more advice would be greatly appreciated.... oh and what advantage would taking a couple shims out of the lower stack benefit me .... i ALWAYS ride trail / old coal mines "spoil banks" . . .plenty of downed trees. . .if ya know what i mean :wink:
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

Replacing the bushings and seals is about it, part-wise.

Putting in springs that fit you would be a huge plus. Is that part of the goings on?

Set the spring preload to maybe 5-8mm or so..NOT the idiot amount the OEM springs have on 'em.

With the correct spring rate, removal of some of the face shims as noted will make the forks more compliant..less jarring/stiff..more soaking-up-stuff like they're supposed to. You will likely ride faster AND more comfortably/confident at the same time. That = more fun.

If you don't like it, you can lay the bike down (oil flows to the top), take out the base valve and put the shims back in.

Nothing lost.

Some experimentation will be required to find what suits you best.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
jimmy97
Member
Posts: 35
Joined: 03:20 am Apr 04 2009
Country:

Post by jimmy97 »

OK , so i;m getting ready to remove some of the shims out of the stack, are there any tricks to getting this stack apart, ? or should i just spin that small nut on it? and any hints on re-assembling the stack? And how do you set the spring preload?
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

If you see the stud is staked..they have not been apart. The stake must be removed before you put a wrench on that nut. You WILL destroy the valve if you force that nut against the stake.

Hints on reassy: Remove half the 24mm (largest..shims against the piston face). If you have 12, take out 6, etc. If you don't have the correct rate springs in your forks (i.e. You weigh 210 and are using the OEM springs)..don't bother messing with the base valve. It won't likely help anything and WILL likely mess up what you've got.

Preload: Spring in, cap threaded all the way on the rod (NOT just against the jam nut..'cuz who knows where that is. Probably at the bottom of the threads and out of the way....but make sure), fork extended.

Uh...obviously the cap is not threaded INto the tube at this point, right?

Measure the distance between the top of the spring and bottom of the cap.
Subtract the thickness of the two cupped washers. What you have left is the 'free' space (length, whatever you wanna call it). Add to that number whatever preload you are after: 'Free' space figured to be 50mm..cut a preload spacer 58mm long to make the preload 8mm.

*50mm is a made up number. Depending on what springs you use, it will be nowhere's close to the actual 'free' space you have in your forks.

Use 1" schedule-40 PVC for the spacer. Cut it square, deburr the cut.

When you put 'em back together, HOLD the cap, TURN the tube to thread the cap. Do NOT hold the tube, turn the cap. THAT will get you scritchy noises in your forks.

..and EVERYbody hates scritchy noises.

**I'm expecting some idea of what's happening here. When I say 'subtract the thickness of the two cupped washers'..that is obviously only the FLANGES of those washers, right? The inner 'cupped' part fits INside the spacer and takes up NO space from the measurement of 'free' space.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
jimmy97
Member
Posts: 35
Joined: 03:20 am Apr 04 2009
Country:

Post by jimmy97 »

oh, this will probably help: i am a 165 lb rider, the forks might bottom once a ride, when they do bottom, i expect it

I will be using the stock springs .. "i think"... .the base valve has 10 shims in it, they are all the same thickness .005 " and then plus the eleventh the one with the larger i.d. is .009".

just curious... where is this 24mm shim??? does this by chance mean .24 mm? if so that equals .009 " not the .005" i am measuring, and yes i am using a starrett calipers that are +/- .001"

have these forks by chance been "gone through" ?
the stakes were not in either of the stacks.
User avatar
Colorado Mike
Gold Member
Gold Member
Posts: 1921
Joined: 11:42 am Feb 25 2005
Country:
Location: Colorado

Post by Colorado Mike »

The 24 mm refers to diameter, not thickness.
Mike

Life's tough, it's even tougher if you're stupid.
'04 KDX220
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

So...all ten of the shims are 24mm?

Be careful taking a stack apart. It is REAL easy to THINK you have several shims separated..and you don't...they will stick together.

If you're keeping the OEM springs, I'd leave the valve alone...especially if the forks bottom now. Removing shims will allow more oil to flow more freely..and the under-rated springs aren't going to hold you up.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
jimmy97
Member
Posts: 35
Joined: 03:20 am Apr 04 2009
Country:

Post by jimmy97 »

all the shims are the same but they are not 24mm, they are closer to 17mm... and yes, I am sure of it there are 10 of them

what about preload, should i still re-set that , with the use of stock springs?
User avatar
Colorado Mike
Gold Member
Gold Member
Posts: 1921
Joined: 11:42 am Feb 25 2005
Country:
Location: Colorado

Post by Colorado Mike »

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?
Mike

Life's tough, it's even tougher if you're stupid.
'04 KDX220
Post Reply