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Rebuilt shock for the first time, quick question

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This is a showa shock from an 06 CRF450. I bled the shock and assembled then filled with 125psi of air. I compress the shock all the way down and let it come up on its own. It comes up smoothly and stops. Only thing is that I can pull it up about 1/8" or so further up before it stops. Is this normal or is there some air in it?

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Sounds like there may be a little air left. Did you compress the shaft a few times before installing the seal head to bleed any trapped air behind the piston? If you feel that you bled it correctly, installed the bladder correctly, and all the air was removed from behind the piston than the problem may be that you only have 125 psi in the resevoiur. You need 160-180 psi of nitrogen depending on your model requirments. This additional pressure may allow the full stroke to return.

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You do need to run closer to 150 lbs. of nitro although 125 is enough to make the shaft return fully. You probably better re-bleed for a 3rd time, it needs to return all the way on its own.

doc

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I had to bleed my shock half a dozen times before I got it good...while your running the piston through the stroke dont let it suck any air by pulling it up too high...

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And don't forget the hammer to tap on the eye to get the shimstack to open up and get the air out of there...

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There are so many small places for air to get trapped in a shock that you have to expect to break it down a few times to get the job done right.

And when you work the shaft in and out you release some of these pockets of air, but then you can generate bubbles that may take a few hours to rise.

On my YZ shocks I install a bleed bolt to deal with this. On the Showas there's no platform for this so I usually do a three-step process of working the air through the system with little to no agitation. However, I do agree that a tap with a hammer on the shaft is good if done within the earlier stages.

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Are you sure your not pulling up on the top out spring? If that was the case the shaft would move back down after you let it go.

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Are you sure your not pulling up on the top out spring? If that was the case the shaft would move back down after you let it go.

Yes, I am sure that I am not pulling it that hard. I have bled this thing 6 times, each time I get the same result. Maybe time is the key, maybe I should let it sit for a while between bleedings to let the air settle.

Just thought about this, the shock is upside down in a vise while I am compressing it and letting it come up. I have not tried it right side up, could that cause this?

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Ok just re-did my own suspension on a 04 CRF450. I learned a few tricks bleeding it. Ok here we go.

1-Put the shock upside down in a vise so the res is facing up.

2-Fill the res. w/ shock oil 1/2 way and let it equalize out on both sides. If it does not give it a BJ. Cover the res. can and blow into it and you will see all the bubble come out the shaft side. You may even have to remove the shock form the vise and tilt it and tap it with a rubber hammer.

3-Now with the res and main body half full grease up your bladder (if your bladder is sucked in like the one on the lft..then replace it. )

bladder_bad.jpg

4-insert the bladder into the res. pushing slowly and you will even see some more bubbles come out.

5-Once the bladder is seated....inflate it w/ 80-100lbs of air. Now even more air will come out the shaft side. Inflate it slowly!

6-Submerg the shock piston in oil and tap it a few time to get the air bubbles out and then let it sit in the oil as you do the next step.

7-Ok now this will require some talent...If you have a 2nd vise great if not....ask a friend or neighbor to hold the shaft. Take a wire coat hanger and insert it into the top of the shaft. Make sure the reb. clicker is full hard. Then while pushing lightly on the coat hanger soften the reb. clicker and you will fell the inner shaft go down. A lot of time this rod will hang even though the clicker is full soft.

8-Ok now that the reb is confirmed full soft and the HSC & LSC is also full soft. Fill the shock side up about 3/4 -7/8 of the way.

9- Now take your time and insert the piston in. As you start to push it down you will see some over flow going bye the piston and out the reb. hole.

10- Now that the piston is in and seated you want to compress it very fast. But when pulling it take your time and make sure you to not induce air via the blow off hole. Compress it very rapidly at least 12-15 times. This will really help blow all the air out.

11- Now comes the shaft rod seal. witht the piston 1/2 way down slowly fill it with oil to the top. Look at your rod seal and there should be a small bleed hole drilled in the side. This little hole is your friend. Pay attention to where it is when you insert it.

12- Now start pushing the rod seal into the oil as far as you can get it in. Take your time. You can either remove a ton of air or put air in. This is were that little bleed hole is your friend. Let it sit here and you should see little bubbles coming out of the small bleed hole. (you can see it on the pic below)

shock_valving.jpg

13-Now for the final push of the Rod seal have a friend or if you can do it yourself slowly releave the bladder of air and push the rod seal in at the same time. It will go in easy. Be quick but do not hurry. Once it is past the lock ring stop and loc it in.

14-Now fill it with your 150-170 psi of air or nitro if you have it. If not fill it with air @ 150-170 psi until you can get it to a local shop and have it filled with nitro.

15-Now at this point if you took your time there should be no air in the shock at all. When you stroke it...it should extent all the way.

Leaving it in the vice run it though the stroke several times and confirm that it is smooth...

*****Remember to give the air time to come out of the oil. It takes a good 1-1 1/2 hours to do this correctly. Most of the wasted time is letting the shock sit and let the air bubble rise on their own.

Hope this helps....

You can check this post out also. DIY Showa Re-Build & Re-Valve

theDogger

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