too much fork oil?

[Y2Z]

I re-did the fork seals on my 02 yz 125 because they were leaking way too much. In my manual it said fork oil level 573ml(which seems like alot to me). So i got it back together and took it out to the track and they were WAY to stiff, i turned the stiffness down as much as i could be it didnt seem to make any difference. The only thing i can think of is too much fork oil, so whats wrong here?

thanks

 

[bike_rider250]

did you put a different size oil wieght in them?

 

[Y2Z]

Nope, put 5 weight in them. Someone said that they need to be broken in but i rode for at least 4 hours and didnt notice a difference. Will lowering the fork oil to 500ml do any damage?

 

[Rotaholic]

Are you sure you put them back together properly? Are your clickers changing the way the shock works? Showa or KYB (Kayba) The shocks will always retain oil, you need to make sure you compress the shock many times when its apart to get all the oil out.
Did you measure how much oil came out.
Did you change the compression/damping settings?

 

[krosser]

As above re oil retention. Does the manual give you an oil height as meaured from the top of the tube down. Usually 120mm or so which is more accurate unless forks are completely stripped.

 

[Rotaholic]

As above re oil retention. Does the manual give you an oil height as meaured from the top of the tube down. Usually 120mm or so which is more accurate unless forks are completely stripped.

Yes this step above is very important, also did you blead all the air out before putting the tops back on, you should compress the shock many times until no more air comes out the top of the oil.

 

[Y2Z]

I'm sure i put them back together properly, and i tried changing the clicks on the forks many times and noticed a SLIGHT difference(18 clicks out on each side which is way softer than stock im sure). I didn't see a point in measuring how much oil came out because much of it had leaked out because of the blow fork seal.

Krosser, this is what confused me, in the front of my manual it said the fork oil amount was 573ml, but in the re-assembly of the fork it said to measure how much oil i put in, Since putting 573ml in seemed more logical i did that. Which should i have done?

How would getting the air out of the oil make a difference, there is already air in the tube when i seal it?

Thanks for the replies ! I really want to get this sorted out before this weekend.

 

[Rotaholic]

Measuring from the top of the shock when it is standing straight up and down is the best way to measure your fork oil. I normally get a piece of wire/steel etc and measure the length that the manual says and then put a zip tie round the mesurement, then I put that in the top of my shock and hold it against the side with the zip tie sitting flush with the top of the shock. Then I fill it up with oil until it reaches the wire/steel etc

Make sense? or you could just buy the proper kit with the syringe etc, but not really worth it if its only something you do once or twice in your life.

Bleeding the forks is as important as blleding your brake lines. Yes there will be air between the oil and the top of your forks but there shouldnt be any oil in the damping circuits etc

Im no expert though, it should all be in your manual.

Your clickers should change your bikes suspension alot. Maybe just whip the tops off again and check that the connecting rod is lining up with the bottom and top correctly. Some are a D shape some are round

 

[rookie517]

too much oil will only affect the last 1/4 stroke of compression

ya wouldn't feel that stiffness in the initial stroke.

 

[Vic]

too much oil will only affect the last 1/4 stroke of compression

ya wouldn't feel that stiffness in the initial stroke.

Not true. Try filling your forks to the top and you'll see what I mean.

 

[viking20]

There is a big difference in filling up a completely dry fork leg with the cc´s of oil the mfg tells you there should be in there , and using the same cc´s in a fork leg that wasnt completely disassembled , there will be lots of old oil left.
So , always use the height measurement instead.
Compress the forks before you measure the oil height , and move the damper rod slowly up and down. It will only take a few strokes and you will feel the damper work evenly through the stroke. Do this untill there is no air left , it usually takes 20 strokes tops to get all the air out.
Next you can adjust the oil level. Adjusting the oil height mainly affects the last part of the stroke , correct , but overfilling the forks with oil will certainly make them stiffer overall......Dont ask me why I know , LOL !

 

[Y2Z]

Thanks alot guys! I was hoping i wouldnt have to take it apart again but oh well. I've got new brake pads coming in so im waiting on those so i can do it all at once, ill let you know how it feels when i hit that double again this Saturday, lol.

 

[rookie517]

i don't think anyone will fill the fork full with oil

that only make the bike unrideable.

that's the reason, most people measure with oil height, there should be a minimum of volume of air in the fork.

or maybe i should rephrase my sentence
ya, fill up full will make it unrideable. :bang:

 

[Vic]

Fork oil level is generally thought to affect about the last third of travel, but that is when it is within the manufacturers specified range. It would probably be more accurate to say that oil level most noticably affects the last third of travel, since it actually affects all of the travel.

Overfilling will definately cause the forks to be too stiff.