CR250R fork seal leaks

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  #1  
Old 05-30-03, 03:06 PM
IWD1
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CR250R fork seal leaks

I have replaced the fork seals on my 99 cr250r, I used a service manual had the correct parts and the correct tools, my friend did his cr250 at the same time and his do not leak. I have replaced the seals twice, there is no nicks scratches flat spots damage etc.. to the sliders or the tubes. When I tore the forks down for the first time I noticed a heavier weight oil in the forks maybe 10 or 20 weight - specified is 5 weight. I do not knopw why the heavier oil was in the forks - originally they were not leaking too much, now they are close to empty after I have rode for a few hours. I have replaced the bushings and followed all directions explicitly, the slider and tubes look round and they are straight, the oil seems to be leaking past the outside of the seals. The forks are inverted the slider is on the bottom and slides up into the tube. I see no damage on the forks anywhere, I do not think a seal was rolled or nicked because both forks leaked both times I changed them with new sets of seals, I have been utilizing the specified oil. Why would the seals leak, I just do not understand it? Is there anything I can do, or has anyone had a similar problem, my bike is a 99 CR250R. any advice is greatly appreciated.
 
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  #2  
Old 06-01-03, 03:05 AM
train460
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Hello
are u useing seals from the dealer or from an aftermarket place.
I have found that all aftermarket seals are crap. buy some dealer stock seals and u will have no problems i bet.
Later
Michael
 
  #3  
Old 06-02-03, 10:40 AM
IWD1
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I purchased Honda replacement seals from Honda. My friend said that it seemed easier to insert my seals than his. I don't know if this means anything.
 
  #4  
Old 06-07-03, 02:15 PM
IWD1
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This must be a stumper of a problem because no one has any ideas. Well I went and bought a service manual and discovered that 400cc of oil (which I used) is at the max reccomended fill per manf spec. Also I turned my rebound 2 clicks past standard and my dampening was set to hard. Even though the manual did not warn anyone from setting the front suspension this way I wonder if the pressure was too great for the seals due to the fact of hard compression and 60cc of oil over the standard settings. Or I wonder if 2 clicks past standard on rebound caused my sliders to come too far past my seals. Could any of these have caused a leak?
 
  #5  
Old 06-07-03, 02:17 PM
IWD1
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One other detail I forgot, the first service manual I used was for my buddies CR250R wich is a 2000 model and mine is a 99, the correct service manual identified some minor differences as stated above but I am not sure that they are significant. Any advice is greatly appreciated and needed.
 
  #6  
Old 06-08-03, 11:48 PM
hal k's Avatar
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Originally posted by IWD1
This must be a stumper of a problem because no one has any ideas. Well I went and bought a service manual and discovered that 400cc of oil (which I used) is at the max reccomended fill per manf spec. Also I turned my rebound 2 clicks past standard and my dampening was set to hard. Even though the manual did not warn anyone from setting the front suspension this way I wonder if the pressure was too great for the seals due to the fact of hard compression and 60cc of oil over the standard settings. Or I wonder if 2 clicks past standard on rebound caused my sliders to come too far past my seals. Could any of these have caused a leak?
wouldn't think so. i have run witht 10cc over specs and full hard on compression w/o blowing a seal.

q - are you making sure you aren't damaging tthe seal during installation? I use a baggie coated in oil when I sslide the seals onto the fork tubes. Is it also both forks or just one?
 
  #7  
Old 06-09-03, 07:16 PM
IWD1
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Hello Hal K

Both forks are leaking, at similar rates, after 2 hours of tearing it up I have oil running down my sliders. This has happened twice. After reading the manual one other thing I forgot to do was bleed the air, I was too anxious to ride, could this be the problem? I am committed to getting this right. Some people may wonder why I just don't take the forks over to Honda of Troy and pay the $125.00 in labor + parts to get the shop to do it. The seals are $34 for a set which isn't hateful. I have the tools so why not take care of my own bike, besides I prefer to know my machine rather than trust someone with my life. There has to be something I am doing wrong on the rebuild.
 
  #8  
Old 06-09-03, 07:20 PM
IWD1
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Oh yeah for the damaging the fork seal question the first time I wrapped the sharp edges where the slider bushing seats, with teflon plumbers tape and slid the seals over and the second time I used electric tape.
 
  #9  
Old 06-10-03, 07:16 PM
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Sounds like you have done everything right, and I agree with your philosophy on doing it yourself, but I have an idea of your problem.

First, the basics...
You said you used OEM seals (good idea, the "Leak Proof" seals from the aftermarket are absolute junk). The part number should be 51490-KZ3-J11 (J21 and J31 are the exact same seals).

It does create problems in the forks to run them at full hard. Not so much with the seals, but with hydraulic lock in the valving. You shouldn't go any firmer than 3 out from full hard. If you need more damping than this (or more than 400cc of oil in the outer chamber) then you have the wrong springs and/or need a revalve for your weight.

The air bleeds are not as much for letting positive air pressure out as for letting air in to remedy a vacuum. The forks flex a little on hard impacts and a small amount of air can leak out while they're down, which creates a vacuum when they extend back out. This problem is made worse by... (drum roll)

Your problem, in all likelihood is worn bushings. If you did not completely disassemble the fork and replace them, odds are they are shot and are letting the slider "rock" inside the tube. A seal can't do anything with tubes and sliders that aren't concentric at all times during the stroke. Pull the forks back down and check the bushings. If the gray coating is worn off of the friction side of them and they are copper colored instead, replace them. If they're as worn as I suspect they are, when you "slide-hammer" the tubes apart I'll bet that rather than drive the outer bushing out, the inner bushing will try to slip inside of the outer one. Just keep at it until you get them apart. The factory bushings are good, or Race Tech makes a good set (called "Ultra Slick", though they don't seem to affect fork action at all).

With a few years on this bike you should go ahead and change the inner chamber oil while you're at it. It's probably long overdue. If you don't know how to do this, post back and I'll walk you through it. If you do know how, I'll offer a tip or two.
First, the lower bolt (the one that contains the rebound adjuster and threads into the leg and onto the outside of the rebound rod) is easy to strip, and you should be careful to torque it no tighter than spec. Also use one drop of blue Loctite where it threads onto the outside of the rebound rod. You'd be better off with the special tool Honda and Race Tech sell to disassemble the lower bolt, but you can use a 15mm wrench (to hold the rod down while you take the rebound adjuster off) in a pinch. Just wrap it in tape so it doesn't score the rebound rod. Be sure to reset your clickers as the act of installing the adjuster will make them move a lot.

FYI, the forks are essentially the same on 97-02 CR250s, with the only major differences being spring rates and valving. The '03 got larger diameter cartridges, but the bushings and seals (as well as the method of rebuild) are the same.

So far: 73, 91, 94, 96 and 02 CR250s under my belt. If you need anything else just post back.

Your friendly neighborhood parts guy
 

Last edited by onourown; 06-11-03 at 06:50 PM.
  #10  
Old 06-17-03, 11:27 PM
IWD1
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I will tear down my forks this weekend I will let you know what
I find, I appreciate your response, I m,ay be needing your help.
Thanks
 
  #11  
Old 06-22-03, 04:18 PM
IWD1
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Well I found what the problem was. I knew it was something I was doing on the rebuild. The big answer is........

The seals were on backwards. I rebuilt them this weekend and looked at the manual real close and noticed in the diagram the writing on the seals and what side it was on. The manual does not clearly explain this. The seals look similar on both sides except for the manf info on one side.

Oh well you live and you learn.
 
  #12  
Old 06-22-03, 08:25 PM
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Well, if there's a bright side at least you didn't have to buy bushings.

It can be a little confusing since the only reference to which way they go is on the little paper that's in the package with the seals (and it isn't terribly clear). Don't feel bad, I missed it in my diagnosis too!
 
  #13  
Old 03-04-09, 05:15 PM
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fork seals

i'm having the same problem i bought a cr 250 99 model and the fork seals are leaking, bbut when you look at the seal it still looks ok. it doesnt look like its leakin from where the seal comes in contact with the fork but from the outer rim of the seal. it just keeps leaking does anyone know wat i should do
 
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