Which fork oil for '00 YZ 250?

sigar

~SPONSOR~
May 10, 2000
152
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I'm about to change the fork oil in my '00 YZ250. What oil should I use? This is the first time that I'll be changing fork oil, I plan to pretty much take the forks completely apart and see what the hell they look like. I'm beginning to enjoy working on my bike more than riding it. What tips do you have for this, any special tools you suggest? Thanks.
 

John Curea

LIFETIME SPONSOR
Feb 29, 2000
177
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Check out Ebay, they have a 46mm seal driver on the auction right now going for 26.00. Item #454618691. I bought the same brand new driver from this seller for 31.00 ( about half price). He must have quite a few , because he has been selling them for a while now.
Good Luck, John Curea
 

Coop37

Member
Oct 4, 2000
317
0
The correct fork oii is KYB 01 oil, set the oil height to 125mm from the top, with out the fork spring, with the fork fully compressed, Depending on your weight, and rider ablity, I ran .44kg springs with the oil height at 128mm, I also changed the rear spring from a 4.8 to 5.0kg.

See ya Coop
 

Jeremy Wilkey

Owner, MX-Tech
Jan 28, 2000
1,453
0
Coop,
KYB 01? @ 125mm Why 125mm? Try more like 105-110 at the lowest.... I would also not waste your time and money with KYB 01... That fork is so soft I can't see why 125 or 128 would be good.

Jer
 

Jeremy Wilkey

Owner, MX-Tech
Jan 28, 2000
1,453
0
confused.gif
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It's funny how the "F" always puts things into perspective... I must be warped..
 

Coop37

Member
Oct 4, 2000
317
0
Hello, earth to jer ??? std oil level is 135mm, that is to soft, that is why we go with 128mm," depending on rider " I ran .44kg springs at 128-130mm, work real good, trust me kyb 01 is the best oil to use, there is cheeper, but it is just that CHEEP !!.. I have tested pj1 01, and race tech very light, and all spectro oils, none work as well as kyb 01, trust me I have done a few of these forks.. If you are running 105mm, you need stiffer springs, or your springs are clapped out ?? that is way to much oil for a 2000 yz 250, that might be a good level for a 99 maybe, ( they dont have the bumpers in the fork, so they take more oil )?

See ya Coop
 

Jeff Howe

Member
Apr 19, 2000
456
1
What DO the 99's have in the forks Coop? Jeeeeeeer, I thought they did. And I thought the 98's did too. Hmmmm...... Guess what Coop. My 00YZ250 doesn't have any bumpers in them, I just went and looked. In fact I found them sitting in my service trailer. They are almost in the trash can. You want them?
 

Jeremy Wilkey

Owner, MX-Tech
Jan 28, 2000
1,453
0
Coop,
Hey man I was not tryingh to slam you, but I would be careful. I get really werid when people make recomendations, and they don't seem to be able to back them up. What works for is great! But when telling other people what to do you had better know what your talking about.. I just wanted you to defend your comments. I like to poke at people and see what they really know.. I was a teacher once, still am I supose and it's just part of fleshing out what we understand. I use this forum as a way to flex my brain..I'm chaleanged to talk about things that I understand more interms of variables than something concrete. Unfortunatley for you I don't agree with your YZ recomendations so I wanted you to elborate, maybe to help me see where you are comming from..

There are some sharp people on this board and as long as you can back it up with your ideas your fine. We are here to learn..

Now that being said What kind of oil reasaech did you do? I have done some myself..and I suspect that I'm not much for being called "cheap".. Quite the oposite infact... So I'll let the gloves fall on this one.. Got anything good.. I love a good debate..

Regards,
Jer
 

Coop37

Member
Oct 4, 2000
317
0
Jer. I am not coming on here to argue with any body, But I did miss the year, I meant 97 yz250, 98-2001 all have bottoming rubber.
The oil I have tested has all been seat of the pants testing, riding and setting up new YZ's & RM's for the past 20 yrs, The oil height you gave is for 97 and older, as I have never ran 100mm of oil in the 98-2001 forks, doesnt mean you cant run that height though, just means if I ran any height more than 120 the forks fell real harsh, ?
as for oil's the pj1 01 seemed to foam up, and I had to blead the forks more often. samr with the rest of the oils, the kyb 01 didnt foam no were near as bad. That is my test, What are your test's you have done !!

See ya Coop
 

Jeremy Wilkey

Owner, MX-Tech
Jan 28, 2000
1,453
0
Coop,
Lots of checical analysis and feild testing. It is my job and all.. (Blantent tongue in check hummor) I wonder what you think actually might cause the fork to be harsh with 10-20mm higher oil.. Also how does the bummper fork have a different oil ht. Does it take up more volume? What are you going to do with the RM's with balder forks.. You do know what oil to set those at? Man is that not going to be real harsh or what? Just some food for thought..

You see a air spring is not going to really cause harshness.. Valving does.. It's speed sensitve not postion sensitive.

Jer
 

wrench

'00 Flappin' Fender [Ret]
LIFETIME SPONSOR
Jun 7, 2000
450
4
Coop,
I really think that you should check out the MX-Tech website link, BEFORE YOU POST ANY FURTHER IN A DEBATE WITH JER, when talking suspension.

JMO

wrench
 

Coop37

Member
Oct 4, 2000
317
0
I belive it is call air over oil, more oil = more air pressure under full stroke, causing stiffer feel, the bumper does take up more room in the fork, therfore less oil is required, also from many years testing, when you raise the oil level, it rasies ride height in the fork, And yes valving has alot to do with it, I tell you what you run 100mm of oil, and then put in 125mm, and you will see for your self, But that isnt what the post is about, it is about changing fork oil on a 2000 yz 250, with is what I am refering to. What are you refering to ?
 

Jeremy Wilkey

Owner, MX-Tech
Jan 28, 2000
1,453
0
Coop,
Do you know that your testostron levels fall all day. Yes A man is most bull in the morning..hum.. Well maybe thats my problem now but one way or the other I can't even imagine a fork riding higher from oil ht. The compression factor of air in the tube is almost nothing till the very bottom of the stroke. Really..

You do have the right idea about volumes but it still is almost completly insignifcant.. Harshness will almost always be casued by valving never anything else beyound structraul or materials standpoint.. (so from one fork the same to the other)

I think the point was really about Oil quality.. The KYB o1 is very cohessive, almost stringy. That does prevent it from being a problem when bleeding but there are other things to consider. For one your air spring prevents your fork for "foaming" durning use..

Mobil 1 ATF as back yard as it sounds is the bomb... Years ago I would have scoffed at my own advice and dismissed it as a farce.. however I have learned a few things since then and as much as I would have made a mochery of anyone suggesting it.. I was wrong.. So if you are more comfortable putting KYB oil in your KYB fork enjoy! I'll use my M1ATF and meerily laugh at my own naive ignorance.. (knowing that my forks work better beacuse of it..)

Regards,
Jer

I'm justing having fun.. Don't take me too seriusly..... K...
 

Coop37

Member
Oct 4, 2000
317
0
Jer, I dont take anyone serious, I know what I know from experience, and nothing eles, Tell me why did they drop oil height when they started using the bottoming rubber cone?
I know they leave enough room in the fork for air & oil at bottoming, but it seems when you put the max oil level in the fork it becomes ? how do I say STIFFER or HARDER ? Why is that ? I talk with ross mieda,( enzo) and Ed shiedler,( yamaha testing) And they gave me good imput on this, I would like to know your imput,

How much oi would you put in a 97 yz250 fork? just wondering.

Thanks for the info, jer

See ya Coop
 

Jeremy Wilkey

Owner, MX-Tech
Jan 28, 2000
1,453
0
Coop,
I put even more oil in a older fork. The actual air spring is very light! Mace calculated it out in a old string and it is like 15-20 lbs of force at full compression.. Almost nothing.. Not that you can't tell but it's just not going to make much never mind for the bike durring 75% of the travel. When Talking to an Engineer or a expert remmember what they say is for the record.. So yes techincally a fork with more oil will make the fork ride higher, but show me a rider who can really aperciate the difference other than say MC or the like.. It only really impacts botoming..

Jer
 

Coop37

Member
Oct 4, 2000
317
0
jer, I raised my fork oil from 135 to 128, on my 2001 yz250, and made a noticeable difference, in ride height, and plushness. ( as the fork now rides up in the softer part of the stroke, meaning less spring tension) It made a world of difference to me.
So maybe the older forks arent so noticeable? but the new stuff, you can really fill the difference, It think that before I changed the oil height, it may not of had the 135mm like it stated in the book. but the fork was much harsher, and the fork didnt sit as high ?

On my last years bike the forks were way to soft, after break-in, so I installed .44kg springs, and changed the fluid to 120, and it was to stiff at the first part of the stroke, I changed the oil to 125, and it was better, but still felt a little stiff, at the first part of the stroke, so I went to 130 mm of 01 oil, and it was real nice, So this is were I am coming from, with my spec's, that you called NG, NFG, etc, So as you can see I spend alot of time on my fork spec's to get things right,( I ride every saturday) As for the mobile 1 ATF, I dont dissagree with your spec, I just dont think it is valved for that oil. but I wouldnt post back on public forum "NG, NFG, etc"

Enough Said !

See ya Coop
 
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