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Fork fluid
Posted: 08:07 am Feb 05 2008
by TPMtec
I've just dissasembled my 01 220 forks and it's time to put them back together. Anyone help with fluid level? What is stock fork oil weight?
Thanks,
Posted: 04:37 pm Feb 05 2008
by canyncarvr
OEM fluid is generally such a mess, I don't know that it HAS a weight.
Call it 5w.
Increasing viscosity is a way to effect rebound..there being no adjustment (clickers) for rebound in the OEM forks.
MX-Tech (Jeremy) recommended Mobil-1 ATF for home service. Most tuners use a hi-falutin' hot-rod fluid that of course is 'The Best'..and sometimes runs $40 a quart.
Mobil-1 has worked well for me. It is generally considered to be 7w, although some will argue 'bout that. I've not done my own drop test to determine my own 'official' vicosity number.
Fluid level varies based on individual preferences. 100mm is 'normal'. I used that and other levels...was happy with 110-115mm. It's easier to add some than remove some...and in any case, isn't difficult to do either.
You could start at 115mm, add 5mm (do the math to relate volume to level change), see how you like it. If you don't, loosen the cap (or the drain screw for that matter) and take out '5mm'.
Howz that?
Posted: 05:33 am Feb 06 2008
by Jeb
I use the ATF as well - cheap, cheap!
Except I use some other brand. But whatever it is, it's the Dextron - Mercron something or other type of ATC (as opposed to the F-type ATF some have in the tranny).
Posted: 11:02 pm Feb 06 2008
by TPMtec
Thanks! I do have emulators on the forks. They were set up for a 180# rider. I'm 210 sticking with the stock springs. I'm going to try 10w first. But how many cc's of fluid. Isn't that easier than measuring heights?
Posted: 11:24 pm Feb 06 2008
by Mr. Wibbens


TPMtec wrote:Thanks! I do have emulators on the forks. They were set up for a 180# rider. I'm 210 sticking with the stock springs. I'm going to try 10w first. But how many cc's of fluid. Isn't that easier than measuring heights?
Only if you know they are totally dry to begin with
Posted: 09:51 am Feb 07 2008
by TPMtec
Completely dry inside. Dissaemsbled cleaned and put back together. Nothing in there but air.
Posted: 03:46 pm Feb 07 2008
by Ondatrail


TPMtec wrote:Thanks! I do have emulators on the forks. They were set up for a 180# rider. I'm 210 sticking with the stock springs. I'm going to try 10w first. But how many cc's of fluid. Isn't that easier than measuring heights?
I've done both, height is way easier.
Don't think oil weight is a replacement for spring rate, but if you don't have the money it will be "good enough" IMO
Posted: 12:04 am Feb 08 2008
by dejovi22
If the manual does not specify cc's of oil and no one in this site knows, just do the measuring from the top...its quite simple. I guess, the best approach was to measure how much oil you had in the forks to start with...but I think it is too late for that.

Posted: 02:31 pm Feb 08 2008
by canyncarvr
Heighth is easier.
Measuring what was in there is problematic. There will be oil stuck to or sitting in all sorts of places.
Get a large syringe from a feed store, grange, animal feed place. Stick a piece of tubing on the end, measure to your preferred heighth, put in oil to over-heighth, suck out the excess.
Of course there's all the pumping, bleeding stuff. You don't dump in oil, suck it down to a level.
I've never concerned myself with a volume of oil to put in because I don't care what it is. I DO want a specific heighth.
BTW...the reason heighth is important is the resulting air shock that's left over. The amount of oil doesn't matter from the standpoint of hydraulics, as long as there's 'enough' in there. The air shock at the top is a big deal. THAT's what you're measuring.
Posted: 03:42 pm Feb 08 2008
by Ondatrail


canyncarvr wrote:BTW...the reason heighth is important is the resulting air shock that's left over. The amount of oil doesn't matter from the standpoint of hydraulics, as long as there's enough in there. The air shock at the top is a big deal. THAT's what you're measuring.
Never thought of it that way

Posted: 04:04 pm Feb 08 2008
by canyncarvr
Unrelated...but, that is always something to watch out for.
It's easy to get involved with the premise put forth..in this case, 'How much oil?'..the following points having to do with how to measure, what to measure and such being quite beside the point of the whole issue.
A lot of time, the PREMISE as proposed is what's wrong..and trying to ANSWER such is a waste of time.
Check a person's argument or standpoint from the beginning. Check it for a straw man component, for sophistry.
Might save you a lot of tail chasing.
Posted: 07:45 pm Feb 08 2008
by TPMtec


canyncarvr wrote:Heighth is easier.
Measuring what was in there is problematic. There will be oil stuck to or sitting in all sorts of places.
Get a large syringe from a feed store, grange, animal feed place. Stick a piece of tubing on the end, measure to your preferred heighth, put in oil to over-heighth, suck out the excess.
Of course there's all the pumping, bleeding stuff. You don't dump in oil, suck it down to a level.
I've never concerned myself with a volume of oil to put in because I don't care what it is. I DO want a specific heighth.
BTW...the reason heighth is important is the resulting air shock that's left over. The amount of oil doesn't matter from the standpoint of hydraulics, as long as there's 'enough' in there. The air shock at the top is a big deal. THAT's what you're measuring.
So, more oil, less air space. Less oil, more air space. Correct? So then doesn't the amount of oil directly tell you the amount of airspace? The interior of a fork has a specific volume of space. I add how much oil to get how much air space? Or am I over simplifiying it?
Posted: 07:45 pm Feb 08 2008
by MXOldtimer


canyncarvr wrote:BTW...the reason heighth is important is the resulting air shock that's left over. The amount of oil doesn't matter from the standpoint of hydraulics, as long as there's 'enough' in there. The air shock at the top is a big deal. THAT's what you're measuring.
That's true. I put reservoir tanks on my YZF's forks and had a hell of a lot of experimenting to get the oil height correct.
.
Posted: 08:01 pm Feb 08 2008
by MXOldtimer
So, more oil, less air space. Less oil, more air space. Correct? So then doesn't the amount of oil directly tell you the amount of airspace? The interior of a fork has a specific volume of space. I add how much oil to get how much air space? Or am I over simplifiying it?[/quote]
I don't mess with MM's I use inches for my peanut brain.
In a new fork I'll start at 5" of oil height. That's springs out and fully compressed. I then ride and go up or down in 1/4"-1/8" increments until I get the feel I want.
Oooooh also I only use Redline oils.
.
Posted: 08:06 pm Feb 08 2008
by canyncarvr
Re: 'So, more oil, less air space. Less oil, more air space. Correct? So then doesn't the amount of oil directly tell you the amount of airspace? The interior of a fork has a specific volume of space. I add how much oil to get how much air space? Or am I over simplifiying it?
Over complicating it, I'd say.
The point is what the air shock volume is. Measuring it directly seems simple to me..as opposed to measuring what doesn't matter..wondering where that makes the actual heighth without considering other factors.
If the point is to know what 'it' is...I'll measure 'it'...not 'that'.
You're more than welcome to pour in XXml if you would prefer.