Author Topic: Replacing fork seals on 81 CB650 with air assisted forks (how to)  (Read 12355 times)

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Offline Blueridgerunner

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The shop manual details how to remove seals without taking the forks apart using a shop press. Now, here is how to do it for us lesser mortals without a fancy press:
remove front wheel, fender, brake assembly, air line between fork tubes.
use 8mm 1.0 bolts (short ones). I fitted O rings to them but not really sure if needed, to plug up the place where the air line was attached. Also, remove the schrader valve from top of RH fork and plug that as well.Remove the fork cap at top of fork (careful) and remove spring. Pour out nasty old fork oil. Using snap ring pliers remove the snap ring and fish out the washers (2) above the seal. Extend the tube all the way and fill to where the threads for the cap are with ATF and replace the cap. Now the neat part:
Use a bar clamp (used to glue up boards and furniture) to compress the fork (we don't need no stinkin shop press :P ). Wrap a rag around the area where the seal is and the seal will ease on out. Mine oozed out slowly, nothing scary. Use your home made PVC seal tool to install the new seal. Congratulate yourself.
Said James "In my opinion,  there's nothing in this world, beats a '52 Vincent and a red headed girl"

Laissez les bons temps rouler

Offline D

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  • 1979 CM185T, 1981 cb650c
Re: Replacing fork seals on 81 CB650 with air assisted forks (how to)
« Reply #1 on: September 12, 2010, 04:23:15 PM »
Hey, thanks for the post was looking all over for info on this. I might have some questions for you soon

Offline F16Viper68

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Re: Replacing fork seals on 81 CB650 with air assisted forks (how to)
« Reply #2 on: November 21, 2011, 02:42:49 PM »
Thanks for input on how to knock this particular task out.  I have just a few things to add.

1. The bolt you need is M8x12 and an o-ring that fits over it.

2. In my case the seal did not come completely out.  Once I got to a certain point the ATF fluid simply leaked out.  I had to pry it out as you would normally.  The picture below is after I had been prying for a bit.

Side Note: I "think" after I removed the c-clip, washer, pressed out the seal as far as it would go via the press, removed the 6mm bolt, I should have been able to simply perform the "slide/hammer" action to pull the seal out the rest of the way.  I didn't think of this till I was done rebuilding both forks. 

3. Don't bother blocking the cap with the schrader valve.  Just use the left side cap on both forks since it only has one hole to block. 







Before


After

« Last Edit: November 21, 2011, 02:57:41 PM by F16Viper68 »

Offline dfoxengr

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Re: Replacing fork seals on 81 CB650 with air assisted forks (how to)
« Reply #3 on: May 03, 2012, 03:51:34 PM »
thanks for the pics. is there just one seal or are there two pieces you replace?

Offline F16Viper68

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Re: Replacing fork seals on 81 CB650 with air assisted forks (how to)
« Reply #4 on: May 10, 2012, 05:47:04 PM »
thanks for the pics. is there just one seal or are there two pieces you replace?

Each fork has one seal and a dust seal. 

Dave...

Offline Blueridgerunner

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Re: Replacing fork seals on 81 CB650 with air assisted forks (how to)
« Reply #5 on: June 04, 2012, 04:01:57 PM »
Thanks for the pictures and update on my post. Additions and/or improvements are always welcome.
Said James "In my opinion,  there's nothing in this world, beats a '52 Vincent and a red headed girl"

Laissez les bons temps rouler

Offline tmac

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Re: Replacing fork seals on 81 CB650 with air assisted forks (how to)
« Reply #6 on: June 08, 2012, 09:04:46 AM »
Wish I could see under that seal!! Im stuck right now tryna figure out where the backup washer goes?? Does it go down in the lower leg or is it just under that seal?? If u could help me I would appreciate it greatly !!

Offline Blueridgerunner

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Re: Replacing fork seals on 81 CB650 with air assisted forks (how to)
« Reply #7 on: June 10, 2012, 01:07:43 PM »
Wish I could see under that seal!! Im stuck right now tryna figure out where the backup washer goes?? Does it go down in the lower leg or is it just under that seal?? If u could help me I would appreciate it greatly !!

Under the seal
Said James "In my opinion,  there's nothing in this world, beats a '52 Vincent and a red headed girl"

Laissez les bons temps rouler

Offline jefe06

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Re: Replacing fork seals on 81 CB650 with air assisted forks (how to)
« Reply #8 on: May 11, 2020, 01:21:49 PM »
Hate to resurrect this, but in the initial write-up the author indicates installing seals using your "homemade pvc seal installation tool".  What is this, just a properly sized pvc tubing to push the seal down and into place?
1981 CB650C bone stock.

Offline Doitdahardway

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Re: Replacing fork seals on 81 CB650 with air assisted forks (how to)
« Reply #9 on: June 04, 2020, 11:36:24 AM »
Yes, I would assume the PVC tool is just a correct sized piece of plastic pipe. You would place it over the entire shock and tap it in with a rubber mallet. My question is, how do you get the fork cap out? Is it just press fit and you grab it with pliers and twist it out?