CSC Blog

This tutorial, as the name implies, addresses fork maintenance.   We stock all parts for the forks, so whatever you need, feel free to call us at 909 445 0900 and we’ll ship whatever you want immediately.

The most common problem for any motorcycle’s forks would almost certainly be leaking fork seals, and in this tutorial we’ll show you how to get to and replace a fork seal on the RX3.

Some people change their fork oil periodically, but the labor involved is fairly significant and we don’t recommend changing the fork oil if you are satisfied with the front suspension or if you don’t have leaks.

Some people like to raise the forks in the fork yokes to change ride and handling characteristics, but we don’t  recommend that.

Finally, you may wish to use a higher viscosity fork oil to stiffen the front suspension; this maintenance tutorial will show you how to drain the oil and replace it with a higher viscosity oil.

Changing the Fork Oil

The first step in working on the forks is to remove the front wheel.   You can learn how to do that in our front wheel removal maintenance tutorial.   You will need to get the front wheel off the ground to do this.

After the front wheel has been removed, many people will loosen the fork cap (but just loosen the cap; do not remove it yet).  We advise loosening the upper fork yoke pinch bolts first if you want to do this.  Other folks like to loosen and remove the fork cap after the fork has been removed from the motorcycle (you can do this if you have an impact wrench, but it is difficult to do without an impact wrench once the fork is off the motorcycle).

The next step is to remove the speedometer cable from the right fork leg (if you are removing the right fork leg).   There’s a composite clamp that secures it.   Unscrew the clamp screw and detach the speedometer cable from the fork leg.

Remove the front fender by removing the four bolts that secure it to the forks.   The front fender can be maneuvered through the forks so that it can be removed after the bolts securing it have been removed.

Remove the two bolts that secure the ignition switch shroud.    You need to remove the shroud to gain access to the upper yoke fork pinch bolts.

Loosen the two upper yoke pinch bolts if you have not done so already.   You don’t need to remove them; they just need to be loose.

The next step is to loosen the lower yoke pinch bolts, but you need to be prepared for the fork leg to drop as soon you loosen the last pinch bolt.   We recommend holding the fork leg with one hand while you loosen the last pinch bolt.  You can get to the lower yoke pinch bolts from beneath the body panels, and you don’t need to remove the body panels to gain access to the lower yoke pinch bolts.  We took them off for this tutorial only to make the parts more visible.

At this point, you’ll have the fork leg off the motorcycle.

Unscrew the fork cap from the fork.  If you did not loosen it first, as mentioned at the beginning of this tutorial, you will need an impact wrench to loosen it.

While you are unscrewing the fork cap, and after you have unscrewed the fork cap, keep the fork in a vertical orientation as you see it in the photo below.  That’s because the fork contains oil, and if you tilt it, the oil will spill out.

Tilt the fork over a container and empty the oil in it.  Note that in this photo, we’ve already removed the fork cap and spring (that’s why you don’t see it in the photo).   When you do this at this  point in the disassembly process, the fork cap and spring will still be attached to the fork.   The fork cap will be fully unscrewed, but it will be attached the fork rod (as you will see in the two photos down).

Empty the fork oil into a suitable container for future disposal.

Each fork leg contains 330 cc (or 11.2 US fluid ounces).   The fork oil that comes from the factory is a fairly light oil, which provides a comfortable ride.   At 210 lbs, I’m what some folks would call a full-figured rider, and I like the ride the RX3 provides as it comes from the factory.   Some people want a stiffer ride if they wish to ride the motorcycle more aggressively in the rough stuff.   You can stiffen the RX3’s front suspension by using a heavier weight fork oil.

At this point, if your fork seals are good (i.e., they were not leaking) and the only reason you took the forks apart was to change the fork oil, repeat the above process for the opposite fork.   Reassemble the forks in the same manner as they were disassembled, leaving the fork caps loose so that you can add new fork oil.  Add 11.2 ounces to each fork.   We advise using a funnel.

CSC stocks fork oils in various weights.  If you wish to stiffen your front suspension with a heavier fork oil, give us a call at 909 445 0900.  Ask to speak with Rich, our suspension specialist, and review your needs with him.   Rich is a real expert in this area and he’ll get you dialed in with the fork oil that will best meet your needs.

Repairing a Leaking Fork Seal

The other common fork maintenance action is repairing a leaking fork seal.   If the fork seal leaks because it was damaged by grit or some other attributable cause, you probably need to only replace the leaking seal.   If the seal started leaking due to age-induced degradation, it’s a good idea to replace the seals on both sides of the forks.  If one leaked due to age-induced degradation, the other is likely to start leaking soon.

Put a wrench on the bolt head inside the fork spring, and unscrew the fork cap from the fork rod that runs though the center of the fork spring.

The fork cap and its washer will separate from the fork rod.

Pull the fork spring completely out of the fork.   Note that the fork spring is a compound spring.  The more tightly wound coils always go toward the lower end of the fork, as you see in the photo below.

At this point, put a shop rag or a paper towel in the opening at the top of the fork (where the fork cap was).    There will still be residual oil in the fork and this will keep it from making a mess.

The next step is to remove the dust seal, and this calls for a light touch.  Use a fine bladed screwdriver (or something similar) and gently tap the dust seal away from the fork upper tube.   Work gently around the periphery of the dust seal, as you see Rich doing in the photo below.   If you get careless here and gouge the fork or damage the dust seal, you’ll need to replace those parts.

Once the dust seal has been removed, you need to reach inside the fork upper with a pick.  You’ll see a raised area in the clip that secures the fork seal in place.  Gently place the pick inside the raised area of the clip, and push inward and toward the opening.   The clip will release.  Remove the clip from the fork.

Now we can pull the fork lower out of the fork upper.   This is not easy.   What you see Rich doing in the photo below is using the fork lower as a jack hammer.   Pull it sharply away from the fork upper while holding the fork upper.  You’ll have to repeat this several times to get the fork lower out of the fork upper.

After you have separated the fork lower from the fork upper, it will look like this.  Note that there are two circular flat clips around the diameter of the fork lower.  These are slider bearings; one is black in color; the other is bronze.  These keep the fork centered in the tube.  Each bearing has a slit in it to allow expanding the bearing so that it can be removed from the fork lower.  The red arrow points to the slit in the upper bearing.  It’s barely visible and it is a fine slit.

Here’s another photo showing the slits in both bearings.

The upper bearing (the black one) rests in an annular groove machined into the fork lower.   We have to expand this bearing diametrically to get it off the fork lower.   Rich did this using a very fine-bladed screwdriver (the one on the right in the photo below) to start the expansion process.  Once he opened the bearing a tiny bit with the fine-bladed screwdriver, he inserted a larger screwdriver.  This allowed expanding the bearing so that it could get out of the fork lower machined annular groove and off the fork lower.   Don’t carried away with this expansion.  The trick is to expand the bearing just enough to get it out of the groove.

After getting the upper bearing off, slide the lower bearing off.

At this point, the fork lower will look like the photo below.

We’re almost done, but not quite.  The challenge now is to get the fork seal over the annular groove without damaging it.  If the seal is leaking and we already know it is defective, we don’t care about getting the fork seal off without damaging it (we’re going to replace it anyway).  But if we are taking the forks apart for any other reason, we need to be careful.   We similarly need to be careful when installing a new seal.   Those edges are sharp, and if we’re not careful, we’ll damage the new seal and have to start all over again.  Some folks use thin plastic (e.g., from a baggy) to cover the annular groove’s edge when removing or installing a new fork seal.  Another suggestion from one our customers is to use electrical tape to cover the annular groove while sliding the seals off of the fork leg.

After removing the fork seal and the dust seal, examine both carefully for any cuts, tears, or degradation.   If there’s even a hint of damage, replace the defective part.   You should also examine the fork lower (which is the part that slides through the dust seal and the fork seal).  If there are any scratches, gouges, or surface imperfections on the portion of the fork lower that slides through the seals, you need to either polish the imperfections out or replace the fork lower.  If you don’t, you’ll just create another leak.

Assembly is the opposite of the disassembly procedure.    After you’ve reassembled the forks, make sure all fasteners are tightened in accordance with the torque table in the CSC RX3 Service Manual torque specification table.

There’s a fair amount of work involved in fork repair (this is one of our longer maintenance tutorials), but it’s a lot less expensive doing it yourself.   And my guess is you’ll reach the same conclusion I have when working on these motorcycles.   We’ve posted 10 or 11 maintenance tutorials now, and one of the things that has impressed me greatly with the RX3 is just how fine a motorcycle it is.   The quality of the internal parts is just awesome.   I used to run factories and machine shops making high performance military aircraft and weapons systems, and the workmanship exhibited in the RX3 is every bit as good as what we built for the US Department of Defense.

Like always, when you finish servicing your motorcycle, go for a ride.   You’ll feel better, secure in the knowledge that your forks were serviced correctly.

I’ve received emails asking about more detailed instructions on front wheel removal.   We covered rear wheel removal with our tutorial on fixing flats, but not front wheel removal.   Hey, you speak, we listen, and here we go!

The first step in removing the front wheel is to remove the front axle bolt.  It’s on the left side of the motorcycle.  The axle won’t come out yet (it’s secured by the pinch bolts on the right side of the motorcycle).

The next step is to lift the front end of the bike off the ground.   If you have our accessory centerstand, the front wheel will be off the ground when the bike is on the centerstand.   If you do not have a centerstand, you need a bike lift or some means of safely lifting the front wheel off the ground.

Once the front wheel is off the ground, loosen the two pinch bolts on the right side of the motorcycle.  You don’t need to remove them; just loosen them.

Slide the front axle out on the right side of the motorcycle.

Roll the front wheel forward a short distance and remove the speedometer drive from the right side of the front wheel hub.

You can now remove the front wheel.   Note that there is only one bushing, and that is installed on the left side of the front wheel hub (it is captured between the left fork and the wheel hub).

Front wheel installation is the reverse of front wheel removal.   A word of caution:  When reinstalling the speedometer drive unit, make sure that the tab in it fits into the slot on the front wheel.

One more note:  I’ve been using one of our test mules for a few of these tutorials, and several of you have written to ask me about the gold anodized wheels.   We’re working the RX3 accessories line, and these are wheels we have in the development process.   They are not yet available, so bear with us.  As soon as they are, we’ll post info right here on the blog.

A few others have suggested we include torque specifications.   We’ll have a torque table in the RX3 Service Manual, and as those of you buying a bike already know, that’s a freebie.   You buy a bike from us and you get the Service Manual for free.

Time to go for a ride, folks!

This maintenance tutorial is on getting to and cleaning the RX3 air filter.   You should clean the air filter every 2000 miles, or more often if you ride in dusty environments.

The first step is to remove the seats.   You might be able to get the air filter out with the seats in place, but it’s a lot easier if the seats are off the bike.  The rear seat pops off using the keyed seat release in the left side body panel.  The front seat is secured with two bolts at the rear.

Remove the left side body panel.   The RX3 now has a two-piece left body panel, which makes air filter removal far simpler than it was with the original one-piece left body panel.

Once the body panel has been removed, you’ll have access to the air filter cover.   You will have to hold the electrical harnesses away from the cover to gain access to the five screws securing it.  Take care not to pull on the harnesses, as this can break the electrical connections.

Remove the five screws securing the air filter cover and remove the cover.

After removing the air filter cover, remove the air filter element subassembly by pulling it out.

The air filter element subassembly consists of four pieces (the lower screen, the filter element, the upper frame, and the screw that holds these three items together.   Remove the screw to separate the four pieces.

The filter element is a serviceable item.   We recommend washing the air filter element in a solution of Simple Green and water.

After washing the air filter element, allow it to dry completely.

After the filter has dried, apply a light coat of air filter oil.   We recommend Drag Specialties oil for this purpose.   You can purchase it from us by calling 909 445 0900.

After repeated washings, or if the air filter element ages, it will ultimately need to be replaced.   If you need replacement air filter elements, again, please give us a call and we’ll be happy to send them to you.

After washing and oiling the air filter element, reassemble the filter element subassembly.  Reinstall the air filter subassembly in the motorcycle, reinstall all components, and you are good to go.

One final word…some folks mistakenly believe their motorcycles will perform better if they take the air filter out.   Maybe that sort of thing made a difference 40 years ago or more, but the RX3 will perform much better with the air filter in place, and the engine will last a lot longer.

Our brake maintenance tutorial covers the following topics:

• Adjusting the brake pedal free play.
• Inspecting and replacing the brake pads.
• Replacing the brake fluid.
• Bleeding the brakes.
• Inspecting and replacing the brake disks.

The RX3 has hydraulic disk brakes on both the front and the rear wheel.

Adjusting the Rear Brake Pedal

You should adjust the rear brake pedal to have 10 to 20 mm of free play.  The adjustment is made with a threaded adjustment shaft and locknut just below the rear brake master cylinder.   First, pull back the rubber grommet over the adjustment shaft.

Loosen the locknut, adjust the free play with the threaded adjustment shaft, and then tighten the locknut.

Inspecting and Replacing the Brake Pads

The front and rear disk brake utilize dual piston calipers.   You should replace the brake pads when either one has less than 1.5mm of pad thickness left, or if you the brake pads are worn such that the groove in the pad is no longer visible.   We stock the brake pads, so when you need a set, give us a call at 909 445 0900.

To remove the rear brake pads, loosen the rear brake caliper Allen bolts as shown in the photo below.

Remove the bolts securing the caliper to the swingarm.

One the rear caliper bolts are removed, slide the caliper rearward, lift if off of the disk rotor, and then remove the Allen bolts holding the brake pads in place.

Once the caliper Allen bolts are removed, the pads will slide out.   Note that the pads are not identical; they must be installed in the correct orientation.  The pad with the large arm (shown at the top of the photo below) is opposite the pistons; the pad without the large arm is situated against the pistons.

Inspect the brake pads to determine if they are worn beyond their service limit (less than 1.5mm thick).  If the pads are worn such that the grooves are gone (visible as vertical slots in the photo above), the pads should be replaced.

Reinstall the Allen bolts in the caliper, position the caliper in its appropriate location, and install the caliper bolts to mount the caliper to the swingarm.  Tighten all fasteners.

Pump the rear brake pedal several times.   Operate the motorcycle to assure satisfactory rear brake performance.

The process for replacing the front brake pads is similar to that described above for the rear brake pads.    Loosen the front brake caliper Allen bolts, and then remove the front brake caliper mounting bolts.   Remove the caliper and then remove the Allen bolts from the caliper.   Inspect the front brake pads and replace if necessary.  Reinstall the Allen bolts, the front caliper, and the caliper bolts.  Tighten all fasteners.   Pump the front brake lever several times.   Operate the motorcycle to assure satisfactory front brake performance.

Replacing the Brake Fluid

You should replace the brake fluid in the front and rear master cylinders every 2 years.   Use only DOT 4 brake fluid.  We recommend Drag Specialties brake fluid, and if you call us at 909 445 0900, we will ship a container to you.

The procedure shown here is for the rear master cylinder; the front master cylinder is performed in a similar manner.

Open the master cylinder by unscrewing the two screws securing the master cylinder cover.   Remove the master cylinder cover and place it in an area where it will not become contaminated.

Using a turkey baster or other suction device, remove as much of the brake fluid in the master cylinder as possible.   Exercise caution to prevent any brake fluid spillage.  If any spillage occurs, wipe up the spilled brake fluid immediately (it will damage painted or plastic surfaces).

Remove the caliper bleed cap and attach a small diameter tube to the caliper bleed fitting.   Route the tube to a receptacle.

Add fresh brake fluid to the master cylinder.

Open the caliper bleed fitting by unscrewing it slightly (turn it counterclockwise to do so) and depress the brake lever to pump brake fluid out through the caliper bleed fitting.   Prior to allowing the brake lever to return, close the caliper bleed fitting by turning it clockwise.

Repeat the process until fresh brake fluid exits the caliper.

Close the caliper bleed fitting and replace the caliper bleed fitting cap.

Add brake fluid to the master cylinder such that the upper level is within 1/8-inch of the top (do not overfill the master cylinder).

Replace the master cylinder cover and the screws securing it to the master cylinder.  Tighten the screws.

Pump the rear brake pedal several times.   Operate the motorcycle to assure satisfactory rear brake performance.

Bleeding the Brakes

If air gets into the brake lines, braking performance will be diminished.   You should bleed the brakes any time the brakes feel spongy or soft, or if the brake fluid drops below the level of the master cylinder view port.   Before you bleed the brakes, you should isolate and correct any leaks.  Again, use only DOT 4 brake fluid.

The procedure is similar to the procedure for replacing the brake fluid.  Open the master cylinder by unscrewing the two screws securing the master cylinder cover.   Remove the master cylinder cover and place it in an area where it will not become contaminated.  Remove the caliper bleed cap and attach a small diameter tube to the caliper bleed fitting.   Route the tube to a receptacle.    Open the caliper bleed fitting by unscrewing it slightly (turn it counterclockwise to do so) and depress the brake lever to pump brake fluid out through the caliper bleed fitting.   Prior to allowing the brake lever to return, close the caliper bleed fitting by turning it clockwise.  Add brake fluid to the master cylinder as necessary.  Repeat the process until the brake fluid exiting the caliper is free of air bubbles.   Close the caliper bleed fitting and replace the fitting cap.  Add brake fluid to the master cylinder such that the upper level is within 1/8-inch of the top (do not overfill the master cylinder).    Replace the master cylinder cover and the screws securing it to the master cylinder.

After completing the above, pump the rear brake pedal (if you are bleeding the rear brake) or operate the front brake lever (if you are bleeding the front brake) several times.   Operate the motorcycle to assure satisfactory brake performance.

Inspecting and Replacing the Brake Disks

You should replace any brake disk that is worn below service wear limits or if the disk is warped.    You can measure disk thickness and straightness without removing the wheel from the motorcycle.  You will, of course, need to remove the wheel if you replace the brake disk.

Use a caliper (i.e., a measuring device; not the brake caliper) to measure disk thickness.  If the disk is less than 2mm thick, replace the disk.

Use a dial indicator with the wheel off the ground to measure disk runout.   Spin the wheel and measure runout.   If the runout exceeds 0.3mm, replace the disk.   You only need to do this if the disk appears to be visibly warped (which is not likely) or if the brakes pulsate when applied.   It’s not likely you’ll ever experience this; in 50 years of riding motorcycles, I never have.

You will have to remove the wheel in order to replace the disk.  Refer to our maintenance tutorial on fixing a flat tire for instructions on how to remove the wheels.

Each disk is secured with 6 Allen bolts.   Use blue Loctite when reinstalling the bolts that secure the brake disk.

And that’s about it, folks.   Time to get out and go for a ride!

See you on the road!

We’ve posted six maintenance tutorials so far here on the blog, and a couple of folks have properly pointed out that it can be difficult to find a specific tutorial hunting around on the blog.   To make things a bit easier, we posted a maintenance tutorial index on the CSC website, and you can get to it here.  It shows all of our maintenance tutorials, it provides a quick link to each, and we’ll update it each time we post a new tutorial.

We’ll be adding several more maintenance tutorials in the next couple of weeks, but we had an interesting conversation in the plant today about how much our riders will save based on what we’ve posted so far.   The concept is intriguing, so we worked up a quick spreadsheet based on 2 years of estimated dealer labor costs and 12,000 miles on your bike during that time.   I realize this is a fairly subjective estimate, but the results are interesting…

Wow, a quick back-of-the-envelope calc indicates that if you brought a bike to a dealer and had only the maintenance actions done that we’ve already empowered you to do through our online tutorials, it would cost about $3,500 in labor charges.  Yep, $3,500.  That’s what you’ll save using our maintenance tutorials and doing the work yourself.   $3,500.   The RX3 motorcycle only costs $3,495.

You do the math…

Our good buddy Juddy, who’s on the list for a new RX3, flew over Long Beach today and grabbed this photo for us…

The folks at the docks are working the backlog.   The Germany is still a ways out, so we’re expecting most of this backlog to be beaten down by the time she arrives.

As always, we’ll keep you posted.