My stiction problem resolved

Questions and comments about converting to beefier forks..
Post Reply
User avatar
skipro3
Gold Member
Gold Member
Posts: 4329
Joined: 11:58 pm Nov 04 2004
Country:
Location: BANNED FOR LIFE!!
Contact:

My stiction problem resolved

Post by skipro3 »

As some of you may know, I recently bought a 2002 KX250 and noticed that the stiction on the forks for the KX was not anywhere near what I'm experianceing with my KDX with KX forks added.

With both bikes side-by-side, I could easily test the ease that the forks would move up and down with pressure to the bars. Long story short: My lower tripleclamp pinch bolts were too tight. Yes, I know there were posts to check them and to set for about 12 or 13 foot pounds of torque and I did. But I decided to completely loosen them and then test. So I had them at maybe 2 ft# of torque and they performed just as well as the KX forks were. I tightend 1 ft# per attempt and discovered that anything over 10 ft# would cause the forks to bind up. I don't know why, but that's what I found. I imagine that 10 is good enough to keep the forks on the bike considering the top clamps are still quite tight. I tested on a rock field I have on my property and it's quite a joy to realize so much improvement by just making this adjustment. I don't have a long dirt or gravel road to test them so I rode down the reflectors on the center line of our street and the forks reacted to those small bumps. I then tightend the clamps back to about 13ft# and sure enough, the reflector bump test revealed that the forks weren't reacting to those small bumps.

I recommend that if you are experianceing stiction to give this a try. I am really happy the fix was so simple. I wish I would have taken this suggestion by ???(I know someone suggested it) but because I did set the torque at the recommended value, I didn't attempt to experiment along those lines.
Let me know if anyone else discovers the same result if having an issue with stiction.
Jerry

I'd rather be a smartass like carvr, than a dumbass like.... well, you fill in the blank!
jafo
Supporting Member III
Supporting Member III
Posts: 835
Joined: 09:17 am Nov 20 2004
Country:

Post by jafo »

I'll try it Ski! My forks are working quite well, but I'm always looking for aittle more. I'll give it a shot today and see if it makes a difference on my bike.

Jon.
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

13# is max on mine before bind, maybe because mine are bigger!:lol:
It definately makes a difference.
I don't think it makes much difference unless they are assembled correctly to begin with.
At first I just slapped them together and they would not move.... then I took my time and assembled them correctly and wala....
*** 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!!! "
jafo
Supporting Member III
Supporting Member III
Posts: 835
Joined: 09:17 am Nov 20 2004
Country:

Post by jafo »

What about the top clamp? Would that cause problems with stiction? I rode yesterday and my forks worked great, but I like looking for alittle more and alittle better. Would the torque on the top clamp make any difference?


Oh and the anti-stiction stuff you were talking about Ski, where did you get that and what did it cost you? Does it require taking the forks apart to apply it? What is involved with applying that stuff?


Jon.
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Top shouldn't matter Jon.... the tubes don't even get close to that unless you are bottomed out...
*** 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!!! "
jafo
Supporting Member III
Supporting Member III
Posts: 835
Joined: 09:17 am Nov 20 2004
Country:

Post by jafo »

OK, thanks.

Jon.
User avatar
skipro3
Gold Member
Gold Member
Posts: 4329
Joined: 11:58 pm Nov 04 2004
Country:
Location: BANNED FOR LIFE!!
Contact:

Post by skipro3 »

Doug stopped by today. I showed him the performance difference in the KDX forks at 10 ft# and at 13ft#. He couldn't believe it!!! He rushed right home to check his on his KX500, and yup, his were sticking due to the lower clamp being too tight. He was about to send his forks out for the 3rd time to get the stack recofigured again.

Some observations:
(first, let me say that I will write up much more in my blog on the KX project bike; KX250 conversion into a woods bike. Also read dirtrider magazine. It has an article on a KX250 in the GNCC. A great list of aftermarket hop-ups that us KDX owners can utilize as well. Oh, and a write up on the KLX650 too.)

I changed the oil in the KX250 forks: 18.5 oz from each leg, 95 mm oil height. The oil was very clean during the initial pour. After pumping and pouring again, each time the oil was worse and worse looking. Still, the 18.5 oz wasn't what I would call real dirty; about as dirty as the tranny oil gets in 100 miles of riding.
The preload was about 4mm. I measured by holding the inner rod up and the spring installed, then screwed the cap on until it just contacted the spring cap. 3 rows of threads remained and it measured at 4mm, maybe just a hair over. Also, with the top cap off, the oil out of the forks and the spring as well, I could slide the outer tube up and down over the innner tube and feel the fork seals stiction. Very little. The drag is very acceptable in my opinion.

What oil brand, weight, and level are you guys running in your KX forks? I am considering Belray 7wt and runnig at 95mm.

Jon: Top triple clamp bolt tension: Just remember to loosen the pinch bolts if you are going to remove the fork caps. Otherwise you will ruin the cap threads.

Carvr wanted me to check the shim stack. He said to just undo the allen head at the bottom of the fork leg with an impact driver. Anyone know what size allen that is and where I could get one?

Thanks!
Jerry

I'd rather be a smartass like carvr, than a dumbass like.... well, you fill in the blank!
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

14mm....AutoZone

I'm running 5wt Honda Showa/Kayaba oil in mine at 135mm. Spec for mine is 120mm.
*** 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!!! "
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Post by KDXGarage »

Thanks for the info, skipro3. I am glad to hear that you got some resolution on your stiction worries. If you can, try to take them apart at least somewhat as the little aluminum and steel bits can float around and get caught in the worst places. As you saw, it is usually pretty clean early in the pour, then gets worse as you continue to pump and pour. The "even worse" stuff is what is left behind. :shock:
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
jafo
Supporting Member III
Supporting Member III
Posts: 835
Joined: 09:17 am Nov 20 2004
Country:

Post by jafo »

You guys are speaking alot of greek to me. Shim stacks, oil levels. What the?

Jon.
User avatar
KDXer
Supporting Member
Posts: 2845
Joined: 12:11 pm Nov 12 2004
Country:
Location: Sydney, Downunder

Post by KDXer »

5wt 110mm here. Still not enough saddle time to comment on performance though sorry.
Image

"I want to die peacefully in my sleep like my grandfather, not screaming in terror like the passengers in his car."
User avatar
skipro3
Gold Member
Gold Member
Posts: 4329
Joined: 11:58 pm Nov 04 2004
Country:
Location: BANNED FOR LIFE!!
Contact:

Post by skipro3 »

I'm glad I checked the oil levels and weight with you guys. I would have stuck in 7wt at 95mm. Now that would have been a bit stiff for trails. Probably o.k. for moto-x though.

Does anyone recall just how much (volume) of oil they used? I know the difference between 95 and 110 might only be about 2 or 3 oz; same between 110 and 135.

Also, why did you choose that weight and oil level?

While I'm begging info off you guys, What stacks are you running? Thanks for the allen size Inda. I'll get one and yank it tomorrow and check on it. Also, the Race TEch set-up on the KDX as well, and report back.
Jerry

I'd rather be a smartass like carvr, than a dumbass like.... well, you fill in the blank!
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Oil weight because riding woods not MX and want the flow....(stock valves)
level because I don't want to slow down abruptly mid-stroke.

I would go 125mm if I was to do it again and I will come fall.

For now...it seems to be the ticket! :supz:
*** 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!!! "
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 »

Wow. 10# isn't very tight.

Lessening the clamp bolts to below what they should be to effect a different problem isn't a good idea.

Do you think 10# is good enough?

Marty looped his 200exc once...it pirouetted, then flipped onto its nose. Tweaked the forks something awful! They was CROOKED! So...not a huge impact to mess them up. Don't know what they were torqued to, but it wasn't much.

From some months ago...
canyncarvr wrote:A REAL waullered out 14mm allen socket
(bold my emphasis.)

But then...so are the words, so I guess I can do what I wanna with'em......;)

That's OK, ski...My hurt feelings will be better (probably) by month's end......


Stacks: Mine is listed already. You're asking for other folkses I presume? Whatever shim stack is used is supposed to be well mated to the piston. Changing stacks to match another bike without knowing what else is in there won't yield the same results. As close as you are to bottoming on .42s, I don't think you have much to give up in the way of hydraulic 'restriction'.


Level: Mine is around 115mm. Didn't make it an exact number. Measured my last syringe setup and it was close enough for starters.

Weight: Mobil1 ATF as recommended by Mr. Wilkey.

The time to take the base valve out is during an oil change. There is a lot of crud that builds up between the cartridge and base valve. I'll bet it's still there in your forks if you didn't take the base valve out to clean it out.

I've never measured the volume. A bit more than a quart for both at the levels I use.

Cap off or not, a bit of pressure on the cartridge will allow the base valve to come off without cartridge movement.

Re: 'then screwed the cap on until it just contacted the spring cap..'

Not quite.

You need to make sure the spring guide is threaded correctly before you will know where the cap is supposed to go. Look at the KYB sticky..something like 18.5mm. I screwed mine down to the point I liked the o-ring compression. Call it a 'tad' compressed. (some scientific lingo for 'ya!)


Yesterday's ride was @ 12fit/lbs on the lower clamps. An improvement, but not as good as the crf250's showas. Good enough that when the dust cleared a few feet before the 14" tree (3-4" off the ground to boot!) lying across the trail...the forks did their job!!



Re: My Banshee...Being happy is a good thing! For about four days next week I'm going to be REAL happy riding all over the dunes! I got one and you don't!!! neener neener
Sour grapes isn't your color, Inda! :wink:

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

bike profile: !clicky!
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Sorry CC... I didn't make my standard "'cept for CC" remark. It's a funny... not meant to insult. :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!!! "
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 »

good grief...I know it was meant as a funny and furthermore I thought it was funny.

If one is intent on insulting me, one would have to try a whole lot harder than that..and count on whatever effort put into that venture to likely come up short...cuz I don't work like that!! :wink:

My response was s'posed to be a funny, too. Well..maybe just plain sarcastic??!! ..on a couple of different levels....

Yeah...sometimes I just kill myself! (uh..explanation: Because I think I am SO funny myself!)


No umbrage taken. Wait a minute...yes..YES..there was!! And I think you owe me a beer because of it! Now THAT sounds good....... :rolleyes:



...but you still wish you had one (quad) :razz: ! Now...I DID say (edited it out), 'Just 'cuz you don't have a quad doesn't mean you can't tell YOUR parents....'

All in good fun!!

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

bike profile: !clicky!
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Are they exclusive? Hmmmmmmmmm???? :shock: :grin:

Come on down from that mountain into the primal ooze and I will buy ya a beer! Import even!
*** 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!!! "
Post Reply