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Author Topic: Showa Fork Rebuild: Seals and Fluid change  (Read 4932 times)
AgentSmith
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« on: March 16, 2008, 11:00:44 AM »

This was done by a buddy named Smash. Thanks to him for his time and effort.

It's always a good idea to clean your bike anytime before you work on it.  As you'll notice I didn't do too good a job and the axle holder has a bunch of dirt on it.  If you drop any of this in the fork it wouldn't be good.  So do a better cleaning job than I did.


CRF450R CRF450X
  Showa Fork Rebuild Procedures / Steps
Required Parts:
  Fork Fluid - We used 5 weight from Maxima
  Pivot Works Fork Seal Kit - or you can purchase just new seals and bushings
  if required. Factory connection makes a superior Fork seal that has a more pliable
  rubber and seals a little better.
 
First off measure
  how high your forks sit above the top triple clamp.
 
 
Remove your front
  wheel and brake caliper.
 
 
Remove your lower
  fork protectors.
 
Loosen your upper
  and lower triple clamps and lower the fork down so you can
  place the fork wrench between the triple clamp and the fork. Tighten the lower
  clamp lightly to hold the fork tube while you loosen it. Once you've loosened
  the
  top cap, remove the fork.
 
Mark down how many
  clicks out you have your rebound adjuster at and then turn
  counterclockwise until it stops.
 
Hold the outer fork
  tube and completely loosen the fork cap.
 
Slide the outer
  tube down from the fork cap.
 
Remove the air bleed
  screw on the fork cap.
 
Drain the forks
  completely. See your owners manual page 87 for how much
  fluid will remain after you have drained the forks.
 
Hand tighten the
  cap and upper fork tube back together. Replace the air bleed screw.
 
Flip the fork over,
  you'll be loosening this bolt The fork center bolt.
 
We used a breaker
  bar and a crescent wrench to hold the fork foot in place.
 
Once the bolt is
  loose, press down on the fork leg and the inner rod will come out of
  the fork. Place a 10mm wrench around the tube between the foot and the center
  bolt to keep it up and in place.
 
Place a wrench on
  the lock nut and a socket on the fork center bolt.
 
Remove the fork
  center bolt.
 

Use the fork center
  bolt to remove the rod down in the fork. Slightly twise the fork
  to remove the rebound adjustment rod.
 
Completely remove
  the rod.
 
Here's the rod and
  adjuster.
 
Remove the wrench
  and let the rod slide back into the fork leg.
 
Use a screw driver
  to pry the dust seal from the upper fork tube.
 
Completely slide
  up the dust seal.
 

Use a screw driver
  to remove retaining ring.
 

Now grab the lower
  fork leg in one hand and the upper fork leg in the other.
  Collapse the tube and pull them apart in the same fashion as a slide hammer.
 
  The lower fork leg will come loose (it makes a mess so be prepared).
  Place the spring back into the upper fork tube. This is what you'll now have.


 
Here's the lower
  fork tube with both the bushings, the washer and the seal.
 
Use a screwdriver
  to pry the upper bushing apart and remove it from the lower
  fork leg.
 
Remove the lower
  bushing from the lower fork leg.
 
Remove the washer
  from the lower fork leg.
 
Remove the seal
  from the lower fork leg.
 
Remove the retaining
  ring from the lower fork leg.
 
Remove the dust
  seal from the lower fork leg.
 
Clean and check
  your lower fork leg for any problems. Any deep nicks can tear
  new seals. Here's a pretty good gouge on one, but we'll run it.
 
Place a sandwich
  bag over the lower fork leg.
 
Grease up the sandwich
  bag so you don't tear the seals as you put them on.
 
Place the dust seal
  on first. Spring facing towards the bottom of the fork.
 
Place the reatining
  ring on next followed by the fork seal. With the spring facing up
  part number facing down.
 
Remove the baggy
  and place the washer back on.
 
Place the Lower
  bushing back into place. If your reusing your old bushing make
  sure to check the inside surface of this bearing. It's teflon coated and should
  be black
  with no silver or copper showing through it. If any of the surface isn't black
  the
  bushing should be replaced. Replace the upper fork bushing but inspecting it's
  outside surface.
 
Place the lower
  fork tube back over the spring into the upper fork tube. Slide
  the lower bushing back down into the upper fork tube.
 

Use the seal/bushing
  driver to press them back down into place again using a
  slide hammer motion. Not much pressure or force is needed for this.
 

Make sure it's seated
  then lower down the washer into the upper fork tube.
 
Press the fork seal
  back into place and use the fork/seal driver to ensure it's seated.
 
Place the retaining
  ring back into place ensuring that it's seated in the grove all
  the way around.
 
Place the dust seal
  back into place.
 
Using your wrench
  again push down on the fork foot and push the outer rod back
  out and place the wrench underneath.
 
Place the rebound
  adjustment rod back into place and ensure it's seated.
 
If the rod is still
  visible its not seated. Use the fork center bolt to twist it and
  drop into place.
 
The rod is properly
  seated in this photo.
 
Screw the center
  fork bolt back into place. Tighten the bolt fully by hand.
 
Check the clearance
  between the lock nut and the center bolt. The sepc should
  be 0.06-0.08 inches of clearance.
 
Tighten the lock
  nut to the fork center bolt and torque to 16 Lbf-ft.
 
Remove the wrench
  from underneath the fork center bolt and let the fork rod
  drop back into the fork. Hand tighten then torque the fork center bolt to the
  axle holder
  and torque it down to 51 Lbf-ft.
 
Here's the milk
  crate I used as a fork older while working on the fork. A rag
  cushions the fork from the garage floor.
 
Loosen the fork
  cap from the outer fork tube.
 
Using a ratio-rate
  determine how much fluid you want in your fork. Subtract the
  amount of fluid left in your fork from the total volume you want (remember the
  chart
  above). We filled ours with 370ml of fluid as recommended in our Factory
  Connection suspenion owners manual. Stock is 338.
 
Flip the fork over
  and pour the fluid into the fork.
 
Tighten the outter
  fork tube and fork cap together. Only snug them with the wrench
  the triple clamps actually compress the tube enough to keep them from seperating.
  So not much force is needed.
 
Let any air back
  out of the suspension from the air bleed screw.
 
Reset your rebound
  adjuster back to where you had them set before.
 
Replace the forks
  back in the triple clamp and make sure you have them adjusted
  as they were before. We set ours at 3MM measured from the upper triple clamp
  to the top of the upper fork tube right below the fork cap.
 
Go ride. So far
  new fluid in forks has always been noticeable to me. These same
  procedures will work for the CRF450R. I'm sure it applies to most SHOWA forks
  as well.
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Paochow
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« Reply #1 on: March 30, 2008, 09:34:03 PM »

This will come in very handy when we rebuild BCRides forks next week. Thumbs up

Thanks.
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It is cold again, why does this keep happening?
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