Done!!!

Questions and comments about converting to beefier forks..
grump99
Member
Posts: 201
Joined: 10:51 am Mar 09 2006
Country:
Location: Harrisburg, PA

Post by grump99 »

Ok pics are in my gallery:

http://www.kdxrider.net/forums/modules. ... _album.php

Looks like the caps were put on backward by someone. The good news is that both stacks are the same. Here are my measurements from top to bottom:

22 mm x 1

16 mm x 1

20 mm x 1

18 mm x 1

16 mm x 1

14 mm x 1

12 mm x 1

I included pictures of the piston. I have no idea if it is aftermarket or not. Any comments are appreciated.

Thanks!

Tony
User avatar
bradf
Gold Member
Gold Member
Posts: 703
Joined: 02:17 am Dec 11 2004
Country: USA
Location: Anderson, SC

Post by bradf »

I would have thought, figgered, thunk, that it would look like

24 3 each
22
20
18
16
14
12

Your stack with only 1 of the 22 and no 24's is very weak. Does the 22 totally cover the piston port holes?
'04 220 w/'01 KX250 USD forks, '02 RM125 Showa shock, Rekluse EXP 3.0, LHRB & all RB'd
grump99
Member
Posts: 201
Joined: 10:51 am Mar 09 2006
Country:
Location: Harrisburg, PA

Post by grump99 »

>|<>QBB<
bradf wrote:Your stack with only 1 of the 22 and no 24's is very weak. Does the 22 totally cover the piston port holes?
Yes. The bottom of the piston is the exact same diameter (22 mm).
User avatar
bradf
Gold Member
Gold Member
Posts: 703
Joined: 02:17 am Dec 11 2004
Country: USA
Location: Anderson, SC

Post by bradf »

That stack is weak and flimsy. There is simply not enough progressive shim resistance behind the piston, unless you weigh 81 lbs. I'd get at least 6 24's, 3 on each BV to put on first before the 22. If you weigh more than 180 you may want 4 on each side. Also, someone tried to make it a 2 stage stack. Maybe the upside down cup was done by the same guy that did CC's.
'04 220 w/'01 KX250 USD forks, '02 RM125 Showa shock, Rekluse EXP 3.0, LHRB & all RB'd
grump99
Member
Posts: 201
Joined: 10:51 am Mar 09 2006
Country:
Location: Harrisburg, PA

Post by grump99 »

>|<>QBB<
bradf wrote:I would have thought, figgered, thunk, that it would look like

24 3 each
22
20
18
16
14
12
Would this be a good set-up to use? I weigh 170#.

Thanks!
IdahoCharley
Supporting Member II
Supporting Member II
Posts: 1005
Joined: 06:57 pm Mar 19 2005
Country:

Post by IdahoCharley »

Grumps - Let me get this right. You have forks you absolutely loved - worked very well and you were in the middle of the clicker adjustment range:

You tore them apart published your stack information and now your going to stiffen the low speed compression by about 40%-50%. You will be thinking "What the Hell was I Drinking" when you ride the bike after the change. :partyman:

So you have a soft base stack. First few shims will likely be shot in a season's riding but you flip the bike, pull the compression valve, replace the worn out shims and start riding it again in 20 minutes with that smile back on your face. What is wrong with that????? :roll: :wink: :mrgreen:

Brad is correct in that your stack may not look normal but if a 22mm shim covers the ports its not a stock piston. I also wondered about the empty groove on the piston but what is important is that the valving works for you and that it is predicable in your riding conditions. Maybe you have a mid-valve doing most of the suspension work for you!! Just my .02.
Last edited by IdahoCharley on 10:31 am Dec 01 2006, edited 1 time in total.
KTM 380EXC Mine
KDX 200 Mark's
TTR 125 L Wife's
KDX 200 Austin's
EC 300 Tyson's
WR430 Husky - mine
grump99
Member
Posts: 201
Joined: 10:51 am Mar 09 2006
Country:
Location: Harrisburg, PA

Post by grump99 »

>|<>QBB<
IdahoCharley wrote:Grumps - Let me get this right. You have forks you absolutely loved - worked very well and you we in the middle of the clicker adjustment range:

You tore them apart published your stack information and now your going to stiffen the low speed compression by about 40%-50%. You will be thinking "What the Hell was I Drinking" when you ride the bike after the change. :partyman:

So you have a soft base stack. First few shims will likely be shot in a season's riding but you flip the bike, pull the compression valve, replace the worn out shims and start riding it again in 20 minutes with that smile back on your face. What is wrong with that????? :roll: :wink: :mrgreen:

Brad is correct in that your stack may not look normal but if a 22mm shim covers the ports its not a stock piston. I also wondered about the empty groove on the piston but what is important is that the valving works for you and that it is predicable in your riding conditions. Maybe you have a mid-valve doing most of the suspension work for you!! Just my .02.
I think you nailed it. I like the forks way better than the stockers. I have not had any adverse handling issues (no bottoming-out or instability). I haven't even fooled with the clickers yet :mrgreen: . No sense in me over-thinking something that works well. I need to tinker less and ride more. :supz:

Thanks!

Tony
IdahoCharley
Supporting Member II
Supporting Member II
Posts: 1005
Joined: 06:57 pm Mar 19 2005
Country:

Post by IdahoCharley »

Grumps - I'd also be interested if you notice any changes in the fork behavior due to the reversing of the cap on the base valve. (I know you reversed it back to the OEM standard configuration.)

I had seen a couple in the past that had been modified so they were shorter (lip cut down) but had never seen any reversed until CC posted his had been reversed. Wondering now if tuners are reversing the cap or modifying the cap to allow more lift (flow) in the BV check valve as a way to soften it up. (I assumed in the past that the spring seating in the base of the cap was necessary but maybe it not. Really don't know just fishing for your impressions - whether or not you can tell any differences.)
KTM 380EXC Mine
KDX 200 Mark's
TTR 125 L Wife's
KDX 200 Austin's
EC 300 Tyson's
WR430 Husky - mine
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 »

This upside down cupped washer thing bugs me. SOMEone has the idea that's good.

It's cupped for some reason, I assume. It being a spring seat is reasonable. The direction of the cup will effect oil flow, although it wouldn't be much in a pressurized/closed system.

If people go to the trouble of reducing the lip (like IC mentions), this is either important, or it's a black myth consistent with a lot of the black hole thinking of 'tuners'.

bradf: Your time on shock dynos tells you anything about this? I can understand the thinking of the sort of thing that IC brought up..but looking at the thing, its diameter compared to the column of oil it sits in..I can't get how such a liddle thang DOES anything fluid control-wise.

But...pretty much the whole system is based on bending shim stock (tough stuff!) metal.

Grump: I second the thinking of tinker less, ride more!

Unfortunately I also understand that it's the tinkering that resolves/fixes/discovers 'stuff'. I have probably 'found' as many improvements in handling, performance and comfort by accident as I have by intent.

Maybe that's what happened with the cupped washer!!

Oh...I've brought this up before..but the method of determing shim thickness has never seemed straightforward to me. I've decided to fix all that by using simple measurments. :wink:

Bradf uses .1mm/.004" shims. Shims in my forks are .15mm/.006". You're likely to find a mix of the two in some stacks. I think the more commonly used shim is the .15mm/.006".

Yes...those inch figures are rounded.

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

bike profile: !clicky!
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 »

OK...I can't stand it.

I'm waiting for SOMEone to say, 'Where's the o-ring on your piston?'

No one has.

How come?

This is another cupped washer thing? MY piston ALSO had no o-rings. I ordered some for a KX piston and they fit, so I used 'em. Between reversing the washer to its 'correct' orientation AND putting the o-rings back on I suppose I ruined some magic secretness of fork technology?

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

bike profile: !clicky!
grump99
Member
Posts: 201
Joined: 10:51 am Mar 09 2006
Country:
Location: Harrisburg, PA

Post by grump99 »

Went out and rode for an hour. Pushed the front end as hard and fast as I could. CC, I felt no difference with the washer reversed.

Big square edges (high and low speed), whoops, pot-holes, washboards, high speed downhill braking, bump braking, the forks seem to work great. Never bottomed, no excess nose-dive, no harshness, no headshake. I rode through an old cow pasture (gopher holes, occasional rock, fairly uneven) in 5th gear pinned. I was standing on the pegs and it felt like I was floating on air. With the stock forks, I probably would have crashed or been forced to let off the throttle. The plushness may be a problem on large jumps, but I don't do those anyway.

Turning seems a bit slower, so I may have to raise the forks in the triples a little more. I am also running a well-worn 756 on the front (came with the wheel). I bet a fresh tire would help the high speed cornering. As IC mentioned, maybe there is more to it than the shim stack. The stacks were ground nicely at the end and put together with thread-lock, which would lead me to believe that pro-action were the last ones to fool with the piston/stacks. However maybe the guy who sold them to me fooled with them. All I know is I like 'em. :mrgreen:

Maybe a better rider would notice deficiencies, but for a such a small investment, I'm gonna slap seal-savers on and ride 'em til they blow up! :evil: Heck for the price of seals, bushings, revalve etc, I could probably find a nicely set-up and maintaned set on ebay, and sell the old ones to off-set the cost. '96-''98 all use the same triples/axle/wheel, so there are lots to choose from.

:twisted: Or maybe I can get a few holiday drinks into the better half and take her to the Husky dealer down the road. They make some sweet enduro bikes. :razz: Just kidding. :lol:

I really do appreciate all the feedback. :grin: Happy holidays!

Tony
grump99
Member
Posts: 201
Joined: 10:51 am Mar 09 2006
Country:
Location: Harrisburg, PA

Post by grump99 »

>|<>QBB<
canyncarvr wrote:OK...I can't stand it.

I'm waiting for SOMEone to say, 'Where's the o-ring on your piston?'

No one has.

How come?

This is another cupped washer thing? MY piston ALSO had no o-rings. I ordered some for a KX piston and they fit, so I used 'em. Between reversing the washer to its 'correct' orientation AND putting the o-rings back on I suppose I ruined some magic secretness of fork technology?
I have one of those o-ring assortments. I put one on and I couldn't get the base valve back in the fork. Said screw it (see above) and put it back together. Did it make yours work better? I sure hope not, cause I promised the wife I would fool with them again until at least easter :roll: . Seriously, she told me if I don't "stop f'ing with the forks and start riding the f'ing bike, I'd be in deep trouble. I love her :mrgreen: .


Tony
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 »

It was too long between rides for me to tell if the o-rings mattered or not. That in itself is curious to me.

But...such a large omission (leaving the o-ring off) does not seem to be a reasonable oversight but something done on purpose. And with NO seal at the piston edge, HOW do the things work for squat at all!!?? You aren't going to be bending any shims when you can just push oil through a big hole left where the seal was supposed to be. Considering the diameter of the piston and the space involved, that's a LOT of oil movement!

With the o-rings on, my BVs went in fine. Mine were NOT from an 'assortment' of o-rings, but from the dealer. The chances of the diameters/thickness/fit of the two being the same would likely be about zip.

A typo for sure...but you PROMISED to fool with them until Easter, 'eh? Lots of time to get that o-ring in there, ride and report!!

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

bike profile: !clicky!
User avatar
bradf
Gold Member
Gold Member
Posts: 703
Joined: 02:17 am Dec 11 2004
Country: USA
Location: Anderson, SC

Post by bradf »

I got deep enough into shock design that I quickly realized that the science was going to take up all my time and I didn’t have the time to do both my government job and play racing. The difference between a Penske and a Pro that we used in Nascar was light years advanced. The dyno print out made understanding easier.
The dyno graph has 4 quadrants: On the left was force + above the zero line and force – below the line. Across the bottom was travel or displacement in inches – on the left side and + on the right side. The force/velocity and the force/displacement was very evident. Changes could be seen so the driver didn’t have to do a test run.

There were straight progressive stacks, linear stacks, and digressive stacks. There were mixes of digressive LSC with progressive HSC. Rebound was usually linear. There was also velocity dependant pistons that were used vs the digressive pistons that blow or dump the oil on large high speed hits. That is what the check plate in the BV is (Don’t quote me on that). The shims were anywhere from .004” to as thick as .025”. There were no cups on the car shocks.

Shims do wear out and some stacks will wear out sooner than others. A 24 hour race used way different stacks that a 2 hour sprint race. The sprint set-up shims would have been fried at Sebring 12 hour…Sebring was the worst and most difficult track because it was nasty rough and shocks could disintegrate.

I could have sent my forks to MX-Tec and Jeremy would have put in set-up. Race Tech would put in something much different. Each would have used a different piston and each would shim accordingly to compliment the piston. Each would have strived to get the quadrants close. There are more than 4 ways to skin a cat.

If you guys are like me you don’t mind trying things. I am done trying now because I found what I was looking for…and it aint Bono and U2! I am glad I didn’t accept “as is” because I wouldn’t have found my set-up. But for some “as is” is OK. I learned that is suspension the better it can do its job the better and funner I can do mine. That was actually a quote from Fermine Valez our best driver.
'04 220 w/'01 KX250 USD forks, '02 RM125 Showa shock, Rekluse EXP 3.0, LHRB & all RB'd
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 »

Who is your shim source?

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

bike profile: !clicky!
IdahoCharley
Supporting Member II
Supporting Member II
Posts: 1005
Joined: 06:57 pm Mar 19 2005
Country:

Post by IdahoCharley »

>|<>QBB<
canyncarvr wrote:OK...I can't stand it.

I'm waiting for SOMEone to say, 'Where's the o-ring on your piston?'

No one has.

How come?

This is another cupped washer thing? MY piston ALSO had no o-rings. I ordered some for a KX piston and they fit, so I used 'em. Between reversing the washer to its 'correct' orientation AND putting the o-rings back on I suppose I ruined some magic secretness of fork technology?
Well CC I was attempting to say something about the missing o-ring when I said ......."I also wondered about the empty groove on the piston...."

I did get to wondering about the reveresed washer allowing a higher flow rate of oil due to allowing the BV check valve increased lift. This in combination with the missing o-ring on the piston you would still give you a restriction (between the piston and inner cartridge) area for the oil to recirculate back into the cartridge. Thinking maybe square edge bumps softening because the cartridge pressure would quickly equalize (I think). This is really just a guessing first thought off the top of my head since I was attempting to identify why someone may do these things. I have read of turners increasing the manual bleed port size orfice but did not have any additional information. Maybe, just maybe - this is someone's idea of that. Bottom line is the system seems to work for Grumps.

P.S. Yep CC you probably FUKED up your forks - took away some turner's magic formula - slowed yourself down by reverting the suspension system towards a stock configuration. No get out to the shed pull those suspenders - put them back to the "as received" condition they came in and give us a report on your new found speed. (actually your stacks always looked too hard on LSC with the (4) 24 X .15mm: I would have assumed (3 or 4) .1mm shims or a single .15 followed by a .1. on the LSC portion of the BV.

A lot of suspension stuff seems to be by trial and error. Many different things to try and many different approaches. Alot of the professional tuners want to keep their secrets (can't blame them) and sooooo many ideas of what works and what doesn't. Soooooo many interactions also taking place in the forks depending upon hardware, hardware changes, shim, lifts, oil viscosity, oil height, etc, etc. That why a good professional tuner is worth paying at least for racers looking at contingency monies. For us trail riders we are likely a half dozen years behind... well on the KDX we are what 15 years behind to start with??? KX technolgy from 92-94 or there abouts???
KTM 380EXC Mine
KDX 200 Mark's
TTR 125 L Wife's
KDX 200 Austin's
EC 300 Tyson's
WR430 Husky - mine
User avatar
m0rie
Supporting Member I
Supporting Member I
Posts: 2220
Joined: 10:25 pm Nov 29 2004
Country:
Location: Crescent City, CA

Post by m0rie »

Closer to 88 for the 95+ KDX's
1989 KDX 200
2007 TTR-50E
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 »

IC wrote:I also wondered about the empty groove on the piston
Yes. You did.

The ONE single sentence I missed ALL day...and it has to be THAT one!

Do you think the 4x22 I have are too thick? Maybe the same number (or even three) shims of the .1mm variety would work better.

Did'ja ever think of that?
.
.
.
.
:blink:

When it comes to things like replacing, rearranging, changing the thickness of shims in a valve stack..I get that. When it comes to taking OUT a critical sealing part (the o-ring), I don't get it at all. Put that together with THEN saying a change from .006" to .004" in a shim thickness matters...and I'm about to cry BS!

A repeat..but this is a large part of why I haven't bothered much with it all. If it's 'cool' to run the piston without that o-ring... then the whole mess is not ever going to make sense to me. (Yes, IC, I did read what you said about it)

Maybe grump is OK with his off..but maybe he'd like them more if they were ON. And there starts the roundy round of changing stuff to see what happens.

Re: 'If you guys are like me you don’t mind trying things.'

That's true in my case.

Re: 'But for some “as is” is OK.'

That's true sometimes, too. In a situation where I am very unlikely to ever understand it, the latter becomes the mother of invention...a necessity, even!

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

bike profile: !clicky!
grump99
Member
Posts: 201
Joined: 10:51 am Mar 09 2006
Country:
Location: Harrisburg, PA

Post by grump99 »

Tried using a smaller size o-ring, found one that fit nice and snug inside the tube :grin: . Will take a ride maybe tomorrow and see if it changes anything. Flipping the cupped washer had no effect as far I noticed.
IdahoCharley
Supporting Member II
Supporting Member II
Posts: 1005
Joined: 06:57 pm Mar 19 2005
Country:

Post by IdahoCharley »

>|<>QBB<
bradf wrote: If you guys are like me you don’t mind trying things. I am done trying now because I found what I was looking for…and it aint Bono and U2! I am glad I didn’t accept “as is” because I wouldn’t have found my set-up. But for some “as is” is OK. I learned that is suspension the better it can do its job the better and funner I can do mine. That was actually a quote from Fermine Valez our best driver.
This is soooo true for alot of us on the forums. Tinker/putter/work over until we find something that we can live with for our terrian and riding abilities. It also true that we only know the best that we have ridden. (Still talking suspension guys.) Its always nice to be able to ride another bike set-up for your weight, when you have a chance, to check out suspension and handling. This does not happen very often for me anymore!
KTM 380EXC Mine
KDX 200 Mark's
TTR 125 L Wife's
KDX 200 Austin's
EC 300 Tyson's
WR430 Husky - mine
Post Reply