CRF450X / CRF450R Honda Showa Fork Seal and Fluid Change

Well this has been in the works for a long, long time.
Showa Fork CRF450X
We’ve finally put all this together and hope that it’ll come in useful to others. This how to should be useful for most Showa forks. But we’ve personally only used it on a Honda CRF450X and a CRF450R.
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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