Need answers on fork oil service please

SATxMotoX

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#1
Ok, I've got a 87 KX 250 that I'm changing the front fork oil in. This bike has conventional style forks.

OK, I pulled the drain plug and pumped the forks mostly clean of oil. Ended up getting about 575 ml's of ugly black oil out of each tube. I filled both tubes back up with 650 ml's of Mobil 1 ATF (added more to help fight bottoming) and reassembled.

Here's my questions:

If my Clymer show that the "Capacity" is 581-589 cc's (19.1-19.9 oz) that's the amount of recommended fork oil to put in, right?

If the Clymer show's the "Oil level" as being 138-142 mm then what does that mean? How do I measure? How do I take into account the fact that I want more oil to help with bottoming?

Also, after I put everthing back together I pumped the forks and noticed that they are squeaking a bit now. Is that normal for a bit after putting ATF in the forks?

Thanks in advance for the help.


Chris
 
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#2
Oil "level" means distance from the top of the fork tube to the height of oil with the springs out and forks fully bled and compressed. You would add oil towards the 138mm height to help on bottoming.

Don't think the oil should be causing squeeking but your seals may be dry.


doc
 

SATxMotoX

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#3
Thanks.

Found the squeaking was coming from the front brake rotor (don't know why I didn't notice it was the brake, not the forks, that was squeaking...must've been paranoia that I did something wrong.)

Thanks again.

Chris
 
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#5
You might also wish to consider a heavier fluid if the ATF don't work out. Maybe like a 15 wt fork fluid. I'm just guessing they may seem a bit soft yet with the ATF.
 

SATxMotoX

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#6
Thanks for the suggestions. Now some more questions:

1. ATF is the equivalent of 7.5wt, yes? What will I gain from going to a heavy (15wt) fluid? Is using heavier fluid a short term solution for undersprung forks?

2. How much is too much fluid in the forks? What I've been told is you add more fluid to help with bottoming. Right now I have 2 more oz in each fork leg than what the book calls for. Also, I only measured by amount I put in, not the "oil level" measurement from the top of the compressed fork. Is that a suitable way to determine how much fluid you have or do you really have to determine that by the oil level measurement?

3. Any suggestions on the rear shock? What would adding more air in the nitro canister (I'd have a suspension shop do it) help with? Should I go up to 200 psi (max is 213 psi)? Will that help beef up an undersprung rear?

Here's my delima...I've got a 87 KX that is a blast to ride but I can't make up my mind if I want to set this bike up proper (i.e. spending some serious cash on reworking the suspension, motor, etc.) or putting that money toward a newer bike. The suspension is WAY soft on me, but since I can't decide what I want to do, I have yet to spend any money on making it right. So, right now I'm trying to find any and everyway possible to get my suspension set up expending the LEAST amount of cash possible. With that in mind, any and all suggestions are VERY appreciated.

Thanks again for ya'lls help.

Chris