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Extended fork tubes?

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Old Mar 13, 2021 | 06:47 AM
  #21  
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Originally Posted by Paul Bowes

6 over 03 FXDL
handles great after the change. Now I’m getting a clunking Sound from the front end on the rebound after hitting bumps/pot holes? Any ideas?
 
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Old Mar 13, 2021 | 05:01 PM
  #22  
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Originally Posted by Paul Bowes
handles great after the change. Now I’m getting a clunking Sound from the front end on the rebound after hitting bumps/pot holes? Any ideas?
Did you cut the new spacers to the correct length?

Dave
 
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Old Mar 13, 2021 | 07:19 PM
  #23  
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Originally Posted by TOE_CUTTER
Did you cut the new spacers to the correct length?

Dave
I cut them to exactly 6” I am not positive that is the correct length. Didn’t even think twice honestly. 6” longer tube 6” of spacer?.

Also put recommended amount of fork oil for original length.

I appreciate the feedback
 
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Old Mar 13, 2021 | 08:30 PM
  #24  
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Originally Posted by Paul Bowes
I cut them to exactly 6” I am not positive that is the correct length. Didn’t even think twice honestly. 6” longer tube 6” of spacer?.

Also put recommended amount of fork oil for original length.

I appreciate the feedback
Do you have the original spacers? A good starting point would be the original spacers + 6".

It would be good to calculate the volume of your forks additional volume. so, 39mm x 6":

36mm ID x 152mm length = 154,717 Cubic Millimeter calcs to putting an extra 5.25 fluid ounces in each fork.

Dave
 

Last edited by TOE_CUTTER; Mar 13, 2021 at 08:38 PM.
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Old Mar 13, 2021 | 08:54 PM
  #25  
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[QUOTE=TOE_CUTTER;19797311]Do you have the original spacers? A good starting point would be the original spacers + 6".

It would be good to calculate the volume of your forks additional volume. so, 39mm x 6":

36mm ID x 152mm length = 154,717 Cubic Millimeter calcs to putting an extra 5.25 fluid ounces in each fork.

Dave there were no spacers in the forks when I disassembled them to do the seals.
Just rebuilt with +6” tubes and added 6” spacer.

so length of tube x diameter gives me my tube volume. How do I calculate the oil amount from that number?

 
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Old Mar 13, 2021 | 09:08 PM
  #26  
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[QUOTE=Paul Bowes;19797347]
Originally Posted by TOE_CUTTER
Do you have the original spacers? A good starting point would be the original spacers + 6".

It would be good to calculate the volume of your forks additional volume. so, 39mm x 6":

36mm ID x 152mm length = 154,717 Cubic Millimeter calcs to putting an extra 5.25 fluid ounces in each fork.

Dave there were no spacers in the forks when I disassembled them to do the seals.
Just rebuilt with +6” tubes and added 6” spacer.

so length of tube x diameter gives me my tube volume. How do I calculate the oil amount from that number?
I put a comma instead of a period on the 154,717. Should be 154.717. The basic formula for calculating cylinder volume π 𝘳˛ 𝘩.

When you cut the spacers and put them in without your front wheel touching the ground, they should be sticking out of the top of the forks 1/2" to 1".

Dave
 

Last edited by TOE_CUTTER; Mar 13, 2021 at 09:28 PM.
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Old Mar 15, 2021 | 12:10 PM
  #27  
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I would put the spacers in the tubes and then fill them to the factory recommended level, fish the spacers out, install the springs, spacer and caps. Saves having to calculate the volume of the spacers, which should be subtracted from the amount of oil (after you add the amount for the additional length).
 
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Old Mar 15, 2021 | 01:10 PM
  #28  
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Originally Posted by John CC
I would put the spacers in the tubes and then fill them to the factory recommended level, fish the spacers out, install the springs, spacer and caps. Saves having to calculate the volume of the spacers, which should be subtracted from the amount of oil (after you add the amount for the additional length).
since the spacers are on top of the springs are they even in the oil?

And if not, would it make more sense to just disregard them in determining the amount of oil?

also, is 6” the correct spacer length for 6 over fork tubes? Makes sense to me but like a lot of things I am not 100% sure.



 
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Old Mar 15, 2021 | 01:12 PM
  #29  
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Originally Posted by Paul Bowes
since the spacers are on top of the springs are they even in the oil?

And if not, would it make more sense to just disregard them in determining the amount of oil?

also, is 6” the correct spacer length for 6 over fork tubes? Makes sense to me but like a lot of things I am not 100% sure.
the stock tubes call for 10.2oz dry as of right now that is what I have in there with the extended tubes.


 
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Old Mar 15, 2021 | 01:37 PM
  #30  
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Originally Posted by Paul Bowes
since the spacers are on top of the springs are they even in the oil?
While you're measuring the oil, you're really determining the volume of the air space at the top. When the fork compresses, that air compresses. You need to ensure the fork can reach its full travel without locking hydraulically. The volume of the spacer reduces the size of the airspace, so needs to be accounted for.

also, is 6” the correct spacer length for 6 over fork tubes? Makes sense to me but like a lot of things I am not 100% sure.
The spacer determines the preload on the spring. If you had no spacer, and you extend the tube 6", a 6" spacer will maintain the original preload.
 
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