Front fork springs ??

[css_elfers]

I went to Ron A's website and there are 3 front fork springs I can get but they dont say what mm they are. The part # is 51401-kcy-761 (two of those) and 51401-kcy-671 (one of these)for the stock spring that comes on the 2004 xr400r its the kcy-761, Is this the one that I want? or should I say is this 42mm??

ELF

 

[JasonWho]

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[css_elfers]

Yeppers I think that link did it. Im around 170-175 without gear so that will put me 185-190 with gear so I'll go with the 40/mm spring, 10/mm of precomp, 90/mm of oil and 5-10/mm of preload. Sound right?? I'm mostly trails and maybe little jumps no mx tracks here.

ELF

 

[KAY DEE EXER]

CC likes his preload in the area of 3MM FWIW. Mine is set at 5MM / 110mm oil level Mobil ATF/ .38's also FWIW. I am yet to test ride it and probably wont as Im getting Race Tech all round. Im pretty sure precomp is preload. I may be wrong too. Good luck tREV. I weigh about 180 in gear.

 

[matt-itude]

I thought the oil range in the manual says 85 to 100.
Jason what i was saying on the 38 mm was in response to you talking earlier about what if someone messed with the stock springs using different preloads.i figure from mesuring the stock spacers, since the stock springs and my new ones are almost identical in length, that the stockers came factory with 30+mm of pre load where as my new springs call for 7mmish. it just seemed like a crazy amount of preload.

 

[JasonWho]

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[css_elfers]

Now that I'm going to be replacing the springs, are the race tech gold valves worth $130 and how hard are they to install. Can I do the xr 400 springs first to see if that is enough then come back later and install the gold valves or would it be easier since I have the forks apart just to do it then?? Also, I know I'm asking alot here but I don't think I quite grasp what preload is/does, what different weight oil does, so on and so forth. Can someone either tell me what each one does or type in some different scenarios so I have a fell for what they do?? Again thanks all for your input and patience

ELF

 

[KAY DEE EXER]

I havent read through these posts recently but these are all the ones I bookmarked when researching springs. A big thanks to CC for his input.

http://www.dirtrider.net/forums3/showthread.php?t=91170&highlight=fork+oil+preload

http://www.dirtrider.net/forums3/showthread.php?t=73293&highlight=fork+oil+preload

http://www.dirtrider.net/forums3/showthread.php?t=90405&highlight=fork+oil+preload

http://dirtrider.net/forums3/showthread.php?s=&threadid=46249&highlight=xr400+springs

http://www.dishers.com/index_Dirtbikes.html

Enjoy reading? :nener: :aj:

EDITED... LMAO Sorry Jason

 

[JasonWho]

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[JasonWho]

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[KAY DEE EXER]

Don't put too much worry into it, or you will end up like me. :)

Whats that? Looking for a manual. :nener: Jus kiddin. I fixed the last 2 for ya. Thanks for pointing it out.Cheers tREV

 

[John Harris]

It is all here in the history, but I believe you use one inch schedule 40 pvc pipe for the spacers. You may not need a full 20' section from Home Depot unless you are a slow learner cutting the pipe for spacers or you want to make a lot of different sized spacers for testing. (Usual spacer for an XR 400 spring is about 3/4" to 1.5" long.)
There are two XR 400 spring rates that are normally used: a .38 and a .41. I am sorry that I do not know the years that the different rates were used. (XR springs are longer and stiffer than stock springs which are about .35.) You can find the correct years of the XR's that you want to use by doing a search here.
You will enjoy the result of the change and it is very easy.
Cheers John

 

[John Harris]

I am sorry guys--I am a better mechanic than computer operator and I posted the above post at the end of the first page and did not get to the end of the thread where all had been covered. Thanks John

 

[Rhodester]

Rethal & John Harris....Sorry, I didn't realize that 1" PVC would fit in the forks (just under 1 3/8" OD). I used 3/4" sch 40 PVC in mine. It seems to be working fine.

 

[rethnal]

Not a problem.... we all learn something in here everyday..... Glad your works!

 

[css_elfers]

Well I'm into it now. I order the racetech 40's today. They are heat temperd and had the same part # as the xr400 springs. An old customer of mine use to own a kawasaki shop in charlotte so he's going to help me. Thanks again all for everything :worship: . I'll let ya know how it turns out.

ELF

 

[yankeefan4life72]

Real good info guys.I too am thinking about my fork springs.I weigh 185 without gear and like to jump.I think I will go with .40 springs.One question though I went to racetech's website and they want $120 for the springs alone.Fredette racing wants $ 70 for 40's.Is there a difference?

 

[JasonWho]

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[KAY DEE EXER]

Dont forget the Eibachs are cold would (collapsers) and the hondas are hot wound (better).

 

[JasonWho]

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[bereal]

Forks

I rebuilt my forks a couple of years ago after blowing out my seals off a 14 drop off. I had them redone by a race tech authorized dealer. They put in Eibach .42 springs and Race tech Gold Valves along with the new seals. What a difference. I'm not sure what everyone else is talking about with the spacers and stuff and using xr springs. Why not use the stuff built for the KDX in the first place! I spent about $430.00 on the rebuild. I weigh around 195 and now think I might have gone one spring rate too soft. The .42 may be right for you.

Eric

 

[Rhodester]

I have Eibach .43kg XR400 springs in my forks with 3mm of preload and there's no sign of them getting sloppy (collapsing) yet. I'm currently 223lbs bare.

 

[JasonWho]

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[Rhodester]

Yes, 996. The box reads 36.7x510mm. I have 1 riding season on them (as far as wear).

 

[JasonWho]

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