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07 kx250f Fork Damper Assembly Wont Hold Seal After Bleeding

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I'm changing my fork seals, and o-rings.  The only thing I should say is I'm reusing the bushing (I thought they looked fine).  

When reassembling my front forks, my damper assembly keeps getting air in it and it doesn't push the rod back out.  I replaced all 3 o-rings on the damper assembly, and put the 190ml of fluid in the tube (with rod extended), then pump the rod slowly several times, measure the oil level, then put the cap back on and tightened it up, but then when i start to pump the rod short distances it almost immediately starts making air gurgling noise.  I've repeated this process several times, both measuring the oil level before putting the cap on and just filling it up crazy like and spilling it all over when i put the cap back in and I get the same results every time.  Twice during the many times I attempted, I got it to hold a pressure and push the rod back out, but only about 1/2 to 3/4 of the way, I still had to pull it out the last 3 inches or so.  Now, I'd be happy with that, but I can't even get that result anymore!

 

What am I doing wrong?!

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I'm changing my fork seals, and o-rings. The only thing I should say is I'm reusing the bushing (I thought they looked fine).

When reassembling my front forks, my damper assembly keeps getting air in it and it doesn't push the rod back out. I replaced all 3 o-rings on the damper assembly, and put the 190ml of fluid in the tube (with rod extended), then pump the rod slowly several times, measure the oil level, then put the cap back on and tightened it up, but then when i start to pump the rod short distances it almost immediately starts making air gurgling noise. I've repeated this process several times, both measuring the oil level before putting the cap on and just filling it up crazy like and spilling it all over when i put the cap back in and I get the same results every time. Twice during the many times I attempted, I got it to hold a pressure and push the rod back out, but only about 1/2 to 3/4 of the way, I still had to pull it out the last 3 inches or so. Now, I'd be happy with that, but I can't even get that result anymore!

What am I doing wrong?!

Here's the picky part of me, why wouldn't you replace bushings??? Very important part of rebuilding. Ok moving on. As you pump the rod did you cover the port holes? Several times is like 10 times for me then I let them sit extended for 15 minutes to let fine bubbles out. What rebuild kit are you using? Double check your O rings.

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Thanks for jumping in to help:

Bushings didn't get replaced because I thought they had a long lifetime, but I do have some handy I'll put on just to be thorough.  
Port Holes, no I didn't?  Those are the two holes on the side of the for right?  When do I cover those?  After I put the cap back on tight right?  It wouldn't make sense otherwise.  How does that help?
I'm not using a kit, i just ordered all factory the bushing, o-rings and seals from motosport.  It was about $100.  

O-rings were new out of the bag and don't seem to have any scaring. 

 

Also, if covering this port hole thing fixes my problem but the rod still is short from coming out several inches, should I be worried?  Or just chalk it up to age?

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Thanks for jumping in to help:

Bushings didn't get replaced because I thought they had a long lifetime, but I do have some handy I'll put on just to be thorough.

Port Holes, no I didn't? Those are the two holes on the side of the for right? When do I cover those? After I put the cap back on tight right? It wouldn't make sense otherwise. How does that help?

I'm not using a kit, i just ordered all factory the bushing, o-rings and seals from motosport. It was about $100.

O-rings were new out of the bag and don't seem to have any scaring.

Also, if covering this port hole thing fixes my problem but the rod still is short from coming out several inches, should I be worried? Or just chalk it up to age?

good on oem parts, always use them over aftermarket. I extend the rod, cover the holes and purge the air out several times as I fill. Push the rod all the way in, fill up to holes then insert valve. Pull down on rod and it sucks the valving in. Once cap is tight, turn over and dump excess oil out of the holes turning it a few times to ensure it all dumps out

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I don't exactly follow why cover the holes with the cap off?  As long as the rod never comes above the fluid level, the system can be purged of air right?  I think my problem might be that air is getting in the port holes after the cap is on, since it seems to purge air fine but then makes gurgling noises after i put the cap on.  I think I recall that if I covered the port holes with the cap on it seemed to work properly.  I'm rather confident the o-rings are not faulty, the bushings wouldn't cause this problem right?  Do they only center and stabilize the assembly?

Edited by Ibanezsvo

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I don't exactly follow why cover the holes with the cap off? As long as the rod never comes above the fluid level, the system can be purged of air right? I think my problem might be that air is getting in the port holes after the cap is on, since it seems to purge air fine but then makes gurgling noises after i put the cap on. I think I recall that if I covered the port holes with the cap on it seemed to work properly. I'm rather confident the o-rings are not faulty, the bushings wouldn't cause this problem right? Do they only center and stabilize the assembly?

no bushing won't cause this. You may be right. It's why I fill above holes then suck the valve body down by pulling the rod

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Well, I gave it another try today (following the manual's directions again) and it worked the first time, rod rebounded fully.  but I then tried to do the second fork the same way and IT failed to hold a seal!  I have no idea what I'm doing wrong.  The only thing I can figure is that the air rose up and out of the fluid overnight on the first fork making a perfect seal today, but that doesn't make any sense, as I put a lot of effort into clearing all the air out of the tube.  I'm still clueless.  

The one thing I'm not doing is leaving the rod in when I insert the valve assembly and then pulling the rod down to suck the valve assembly in.  That goes against the manual and the motosport youtube video.  Also, since I got a perfect result without that on the first fork today - I'm thinking the problem is elsewhere.

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Well, I gave it another try today (following the manual's directions again) and it worked the first time, rod rebounded fully. but I then tried to do the second fork the same way and IT failed to hold a seal! I have no idea what I'm doing wrong. The only thing I can figure is that the air rose up and out of the fluid overnight on the first fork making a perfect seal today, but that doesn't make any sense, as I put a lot of effort into clearing all the air out of the tube. I'm still clueless.

The one thing I'm not doing is leaving the rod in when I insert the valve assembly and then pulling the rod down to suck the valve assembly in. That goes against the manual and the motosport youtube video. Also, since I got a perfect result without that on the first fork today - I'm thinking the problem is elsewhere.

I use that technique every time with out one issue. It was shown toe by FC. I will also let them sit after I purge the rod for 15 minutes to let all the micro bubbles find their way to the surface.

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... and put the 190ml of fluid in the tube (with rod Extended...

What am I doing wrong?!

190ml is the volume that stays in the cartridge after bleeding. you have to overfill it to be able to

bleed the air , so fill it with approx. 205ml.

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190ml is the volume that stays in the cartridge after bleeding. you have to overfill it to be able to

bleed the air , so fill it with approx. 205ml.

I honestly never measure inner chamber, I over flow it to guarantee zero air

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mxracermx's way of doing it will work i just never thought of pulling the rod out to suck the cap down ( good idea ) will try that.

 

What i do is as per the Kawasaki Manual which is different to the Yamaha manual BTW and is the same forks ( just some useless info ) the Youtube video might be Yamaha's way,

I fill the housing to just above the holes after i have bled all the air out, then keeping the rod pushed all the way in i slowly put the cap in keeping the holes blocked with the cartridge resting lightly on the end of the rod on cloth's, then as i push the cap down i let the rod slowly come out untill i can get the cap on, normally works the first time.    

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I honestly never measure inner chamber, I over flow it to guarantee zero air

 neither have I.

I meassure the oil level, which is 150mm (when I remember correctly) when removing the BV assembly, so I refill it to a level of 135-140mm

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