On our rear suspension, the swingarm and its pivot bearings bear the brunt of longitudinal (acceleration, deceleration, hitting a pothole, etc.) and lateral (cornering, wind gusts) forces. The rear shocks have one job only: to provide support and damping for the suspension. The only forces the shocks see are direct up-and-down.
The front suspension is completely different. Our front forks not only have to provide support and damping, they have to handle every other force we throw at them - and by far braking is the most brutal force. Under heavy braking, the front forks must be able to handle in excess of a thousand pounds of longitudinal force, while at the same time easily sliding up and down to absorb bumps - and to provide the suspension required against the diving force created by the braking. So it's really a miracle that the forks work as well as they do.
The above image is the basic layout of our front suspension system. Inside the forks are a set of one or more springs that provide the support to hold the bike up and cushion against impacts. The upper, or fixed forks, are a set of smooth, chrome-plated cylinders that slide up and down inside of the lower forks, or hydraulic chambers. The forks are filled with a thick oil. This oil is forced through small holes when the fork is compressed. This limits the speed at which the fork can be compressed, and also the speed at which the spring can expand the fork. This is called damping.
There are also bushings in the fork. These are teflon-coated sliders inside the fork that allow the fork to handle very strong forces and yet still slide up and down. Lastly, at the top of it all is an oil seal, whose job is to keep the oil inside the fork.
Over time, the bushings wear out, as do the oil seals - particularly if the chrome fork tubes are dirty, which cause accelerated wear. When this happens, you will start to see evidence of oil on the outside of the fork, as seen here:
You will need:
- A Honda oil seal/dust cap kit, one kit for each fork, available from Cyclemax: Fork Seal Kit
- A Honda slider bushing and a guide bushing, one set for each fork, both available from Cyclemax: Front Fork Bushing
- Fork oil, one liter
Here are the Honda part numbers:
Dust Cap/Oil Seal set: 51490-MN8-305
Slider Bushing: 51415-KCR-003
Guide Bushing: 51414-KCR-003
1. To begin, the procedure, the motorcycle needs to be lifted so that the front wheel is in the air. To do this, I use a motorcycle lift, positioned so that it is lifting the motorcycle frame. If you don't have a motorcycle lift, you can leave the motorcycle on the center stand and put a standard automotive trolley jack under the engine block, near the front of the bike. This will lift the front wheel into the air. Be careful when working with the bike this way, as it is not as stable as it normally is!
2. Lifting a heavy bike like a Goldwing with a bike lift can make it somewhat wobbly and unstable. For safety's sake, always strap down your bike when it is on a bike lift.
3. When lifting the bike on the lift, it can become slightly unstable in the longitudinal axis. Once the bike is lifted, I slide some pieces of wood under the rear wheel, then gently lower the bike until the rear wheel touches the wood. This stabilizes the bike and keeps it from rocking from end to end while you work.
4. Once the bike is lifted, the front wheel will be several inches in the air.
5. Pull the rear of the front fender cover to release the post from its grommet. Carefully release the two tabs from the front of the cover (next to the fork) - these tabs are easily broken, so be careful! Remove the cover. Repeat on the other side of the wheel.
6. Remove the allen bolt holding the top of the wheel cover. You may have aftermarket accessories such as the wiring and light bracket shown in this picture. If that is the case, keep in mind how they fasten, so that you can refasten them when reassembling.
7. Remove the two allen bolts from the bottom of the wheel cover.
8. Note that the two allen bolts on the bottom of the wheel cover have a collar - don't lose the collar!
9. Remove the wheel cover. Repeat the process on the other side of the wheel.
10. Note the brake line stabilization bracket that goes on top of the wheel cover. The top allen bolt goes through both of these brackets, then through the wheel cover, then screws into the fork. There are two brackets on each side, and both of them are stamped "L" or "R" to identify which side of the wheel they are from. The two brackets on each side link together at the back, go around the brake line, and then go together at the front, where they are fastened, along with the wheel cover, into the fork. The inside bracket has a small flange that fits into the hole in the plastic rotor cover.
11. Remove the lower allen bolt holding the brake caliper bracket to the anti-dive piston.
12. Remove the upper caliper bracket bolt.
Helpful note: When removing the left caliper, remove the LOWER bolt first, then the upper bolt. On the right caliper, remove the UPPER bolt first, then the lower bolt. When installing, do the reverse. This prevents the calipers from rotating when trying to remove/install them.
13. Pull each caliper back off the brake rotor, and then away from the wheel. Once the calipers have been removed from the wheel, do NOT depress either the brake lever or brake pedal, as this will move the pistons out, and you will not be able to fit the calipers back over the brake rotors.
14. Using a bungee, rope or wire, hang the caliper so that it is not suspended using the brake line.
15. Using a Philips screwdriver, remove the screw holding the speedometer cable into the speedometer drive.
16. Pull the speedometer cable rearward out of the speedometer drive.
17. Remove the two allen bolts holding the plastic fork protector in place.
18. Remove the fork protector. This protector helps keep dirt off the forks, to prolong the life the oil seal.
19. Using a 22mm socket, loosen the axle bolt on the right side of the wheel.
20. Remove the axle bolt from the axle.
21. Loosen the axle pinch bolts on both sides of the wheel.
22. Remove the axle pinch bolts and the rotor cover brackets.
23. Looking at the right side of the wheel, you can see the end of the axle now that the axle bolt has been removed. This axle needs to be pushed out the left side of the wheel. Using a socket extension or small piece of pipe is a simple way of pushing the axle out. You should use something that is smaller than the opening, but larger than the axle itself, so that it will push on the end of the axle, and not damage the threads inside.
24. A couple strikes with a hammer will push the axle through the right fork leg.
25. Once the axle has been pushed a couple of inches, it will easily pull out, releasing the wheel. If there is resistance, it is the weight of the wheel itself binding the axle. Lift the wheel slightly while pulling the axle out.
26. Set the axle down where it will not get dirty, and roll the wheel out from between the forks.
27. Pull the spacer free from the left hub of the wheel. Pull it free, so that it can be cleaned. Now is a good time to check the wheel bearings. They should turn smoothly, with no lateral play.
28. The speedometer drive is press-fitted into the right hub of the wheel - pull it free, so that it can be cleaned.
29. Roll the wheel free of the forks. NEVER lay the wheel down on the brake rotor - this can damage the rotors, and they are very expensive to replace. To set the wheel aside, lean it up against a wall so that only the rubber tire touches both the wall and the ground. Or, set a couple 4x4 blocks of wood on the floor at approximately the diameter of the wheel, and set the tire down on the blocks, so that the brake rotor goes between them.
30. Remove the four bolts fastening the two forks to the fender. In this picture the bike has a SuperBrace installed - your bike may or may not have a fork brace (this is an aftermarket item).
31. If you have a fork brace, pull it upward to remove, as in this picture.
32. The bracket on the inside of the fenders may fall free, or you may have to pull it out, depending on how dirty the insides of the fenders are. This bracket is where the four bolts from the forks (or fork brace) screw into.
33. Remove the 10mm bolts from either side of the forks. Support the rear of the fender while doing this.
34. Gently remove the rear of the fender.
35. Remove the 10mm bolts from the front of the forks. Support the front of the fender while doing this.
36. Gently remove the front of the fender.
37. You will now have the two forks hanging, unsupported.
38. Put a drain pan under the forks to catch the fork oil.
39. Note that once the forks are unsupported, they can rotate (relatively) freely. The only thing that keeps them aligned with one another is the brace and the axle.
Note: For those who are using a portion of this article to simply drain and refill their fork oil without rebuilding their forks, the fork oil can be drained without removing the axle or wheel:
41. Inside the fork as shown is the drain screw. Push the driver into the drain screw and remove the drain screw.
42. If the fork rotates, preventing you from removing the drain screw, push the axle through the left fork, and partially into the right fork. This will prevent the right fork from rotating while you unscrew the drain screw.
43. Once removed, the fork will begin to drain.
44. The same technique can be used for the left fork. Insert the axle partially into the INSIDE of the fork, and brace it against the front of the left fork while unscrewing the drain screw.
45. This bike had regular fork oil in the right fork (see above) and automotive ATF (automatic transmission fluid), which is red, in the left fork. ATF is an acceptable substitute for fork oil.
46. The drain screws have copper crush washers used to ensure a seal. If the copper washer is not there, make sure it isn't still stuck up in the fork. Honda specifies that these washers should be replaced at every fork oil change - but the only place I have found these washers to be available is from Honda, and I rarely actually change them.
Leave the drain screws out, and allow the forks to drain.
47. Remove the handlebar bridge by gently lifting the back posts from the rubber grommets, then gently pulling the front tabs free.
48. Remove the inner fairing covers by starting with the tabs at the back, then working around to the front.
49. Gently pull each cover free and set aside.
50. Unscrew the fork cap covers and set aside.
51. If you have an SE, you will have a schraeder valve in the top of your fork. Aspencades have a female hex fitting instead.
52. Using a deep socket, remove the schraeder valve.
53. Using a wrench, loosen each of the pinch bolts on the top of the triple tree.
54. Using a hex driver, loosen both hex bolts on each fork.
55. Pull the fork down and free of the bike.
56. Set the forks down somewhere clean - remember, you don't want any dirt or grit on those fork tubes!
57. Next, we are going to remove the springs from the fork. This step can be dangerous, as there is a tremendous amount of force with the springs compressed inside. Do NOT attempt to remove the fork cap without a tool of some kind. Several things will happen: The cap's threads will let go when it is ALMOST out, tearing out the threads on the cap and/or the fork tube, the cap will shoot across the room with great force, and lastly you can be seriously injured.
Many people have manufactured their own fork spring removal tools using pieces of wood and threaded rod. I decided that I do this often enough that I would spring for the actual Honda tool. It works on several different models of Honda motorcycles (including all Goldwings) and is a quality (if not overpriced) tool. I bought mine for $138 from Cyclemax. The part number of the tool is: 07KMF-MT20300
They are still available today from Amazon although the price has gone up.
58. The tool has a reversible driver on the end of the threaded rod, which can be reversed by pulling it off the rod and pushing it back on the way you require.
59. For SE's, install the driver with the large end down, as shown in the picture. For Aspencades, reverse the driver so the small end is down.
60. Place the tool over the top of the fork tube so that the very top of the tube is even with the bottom of the tool's opening. Tighten the pinch bolt.
61. Wind the threaded rod downward making sure that the driver is lined up with the fork cap.
62. After it is engaged, continue winding it down until resistance is felt. Do not tighten.
63. Use a wrench to turn the driver, which loosens the fork cap.
64. After each 1/4 turn of the driver, loosen the threaded rod slightly. The idea is that the threaded rod of the tool will maintain the pressure against the spring, so that the threads of the cap and in the tube are not under any pressure as it is removed.
65. At this point, the cap's threads are no longer engaged, and the threaded rod can be wound back to relieve the spring's pressure.
66. Continue to wind the threaded rod out until all pressure is released from the spring.
67. Once pressure is released, loosen the pinch bolt on the tool and remove the tool from the fork. You can see how much the spring was compressed into the fork!
68. The threads on the fork cap are quite fine, and had it been unscrewed without the tool, the tremendous pressure from the spring would have torn the last couple threads out as it was unscrewed. Note the O-ring on the fork cap to maintain a seal.
69. Pull the spring from the fork tube and set it aside somewhere where it will not get dirty. Some bikes will have multiple springs with spacers and washers. If this is the case with your bike, take note of which order they come out, so that you can reassemble them in the same way. Or better yet, replace the springs with a set of Progressive fork springs, which will improve the ride of your bike immeasurably!
70. Using a screwdriver, very gently pry up the dust cap on the top of the lower fork.
71. Pull the dust cap up and off the fork tube. Discard the dust cap.
72. Looking down the top of the fork, you will be able to see the locking ring. This is what prevents the oil seal from being pushed out of the fork. It sits inside a slot on the inside of the fork tube.
73. Using a small screwdriver, very carefully hook one of the indentations of the locking ring near the end, and pull it up and out of the fork. Be VERY CAREFUL when doing this not to scratch the fork tube! Any scratches on the fork tube will quickly cause oil seal failure once reassembled. If you're worried, you can try using a plastic pick or other plastic tool for this step.
74. Pull the locking ring up and off the fork. Keep this item, as it will be reinstalled.
75. While holding the fork lower securely, slam the fork tube vigorously up and out of the fork lower several times. You will see it start to drive the oil seal out of the fork.
76. Here the oil seal has been driven out of the fork lower.
77. Pull the entire fork tube out of the fork lower. This is what you will see, in the correct order. Gently pull everything except for the slider bushing up and off the fork tube.
78. With a screwdriver, gently pry apart the slider bushing. It is very thin, and not hard to pry apart.
79. While spread, pull the bushing off the bottom of the fork tube.
80. Another view of the parts as removed from the fork tube. Before installing new parts, clean the fork tube of any foreign material (brake cleaner works well for this) and wipe it completely clean. Next, coat it with a layer of fork oil.
81. Here are the old bushings from this fork. Note how the guide bushing is worn, and the teflon is worn and scratched on the slider bushing.
82. In comparison, here are the new bushings.
83. Lightly coat the new slider bushing and the fork tube with fork oil, and very gently slip it over the end of the fork into the slots in which it fits. Coat the new guide bushing with fork oil and slide it down the length of the fork tube next to the slider bushing.
84. Looking closely, the back-up ring is chamfered on one side - the edges on one side are rounded (chamfered), while the edges on the other side are much sharper. Slide the back-up ring down the fork tube with the chamfered side toward the slider bushing and the sharper side toward the oil seal.
85. Looking at the oil seal, it is tough to tell which is the top and which is the bottom. To help you identify which is which, this is the top of the oil seal, which faces the dust cap.
86. This is the bottom of the oil seal, which faces down toward the back-up ring. It has a deeper ridge inside it.
87. Generously coat the fork tube with fork oil. If the top of the fork tube (where the cap screws in) has any burrs, wrap the top in electrical tape before installing the oil seal. Any damage to the inside of the oil seal will cause leaks!
88. Generously coat the inside of the oil seal with fork oil and slide it onto the fork tube.
89. Spray out the inside of the lower fork with a solvent to remove any existing used fork oil. Brake cleaner works well. Make sure the top inside of the lower fork is clean, so that the dust cap seals properly.
90. Pour fork oil down the sides of the lower fork to coat it, as well as wash out any residual solvent.
91. Carefully insert the fork tube down into the lower fork as far as it will go.
92. To drive the oil seal into place, I use this Motion Pro Fork Seal Driver - a fantastic tool. However, you can do the same job with an appropriately-sized piece of PVC pipe.
93. Slam down onto the oil seal to drive it into place.
94. Carefully insert the lock ring into place, pushing it down until it snaps into its slot.
95. Coat the inside of the dust cap with fork oil and slide it down the fork tube. Press it into place so that it seals correctly.
96. Temporarily insert the spring into the fork tube.
97. Invert the fork and rest it on the spring as shown. This keeps the piston pressed up against the bottom end of the fork so that the drain screw can be inserted.
98. Insert and tighten the drain screw.
99. You can partially insert the axle into the fork in order to give you sufficient torque to properly tighten the fork screw.
100. To fill the forks, I fashioned a sort of dipstick from a piece of wire, and a large syringe. The dipstick should be 239mm for 1988-1994 GL1500's, or 194mm for 1995-2000 GL1500's.('95 +)
101. With the fork upright and the SPRING REMOVED, push the fork tube down into the fork lower as far as it will go.
102. Pour fork oil into the tube until it is approximately the correct depth. Slowly pump the fork tube up and down as far as it will go in each direction at least ten times to remove all air from the fork lower.
103. Using the dipstick, make sure the fork oil reaches exactly the end of the dipstick. If not enough, add oil until it reaches the dipstick. If overfilled, use the syringe to siphon off small amounts of fluid.
104. Insert the spring (and spacers, if used) into the fork, and place the fork cap on top of the spring.
105. Place the fork spring tool onto the cap and make sure the driver properly engages the fork cap.
106. Retract the threaded rod all the way, then compress the spring enough to install the tool onto the tube. Tighten the pinch bolt.
107. Wind the threaded rod down, compressing the spring, until you feel SLIGHT pressure. At this point, begin using a wrench on the driver to screw the fork cap in place. After every 1/4 turn, screw the threaded rod in slightly, to ensure the spring pressure remains on the threaded rod, and not on the fork cap threads.
108. Once the cap is fully threaded, remove the fork spring tool. Do not torque the fork cap at this time.
109. Temporarily install the schraeder valves (finger tight) to prevent leakage during installation.
110. Push the fork tubes up into the triple tree. The fork caps should be level with the top of the top triple tree. Torque the upper pinch bolts to 8 ft-lb.
111. Tighten the lower pinch bolts to 40 ft-lb. Now that the pinch bolts are tight, remove the schraeder valve and torque the fork cap to 17 ft-lb.
112. Reinsert the schraeder valve and snug it (not too) tight.
113. Reinstall the fork cap covers.
114. Reinstall the fairing inner covers, starting at the top and working down around the bottom and then the inside.
115. Reinstall the handlebar bridge, inserting the tabs first, then the posts into their grommets.
116. Rotate the forks so that they are facing correctly.
117. Replace the fender front, and bolt it into place.
118. Replace the fender back, and bolt it into place. Thread the speedometer cable through the hole on the left side of the rear of the fender back.
119. If you have a fork brace, push it into position now.
119. Push the fender bracket into place, and hold it in position.
120. While holding the bracket in place below, tighten the forks (and fork brace, if installed) into place.
121. Install and tighten the fork protector into place.
122. A minute or two with some brake cleaner and a shop cloth will remove the dirt and grime from the speedometer drive. Pack the inside of the speedometer drive with grease.
123. Note that on the inside of the right fork, there is a tab. This tab engages a tab on the speedometer drive, to prevent it from rotating with the wheel.
124. Here is the tab on the speedometer drive.
125. When the wheel is reinstalled, the speedometer drive must be rotated so that the two tabs are butted up against one another as shown.
126. Clean the axle, and coat it with a thin coating of grease.
127. After cleaning the spacer, reinsert it into the right wheel hub. Pack the dust seal lip with grease.
128. Coat the speedometer gear drive in the hub with grease, then insert the speedometer gear drive.
129. Roll the wheel between the forks and push the axle in from the left side. Tap the axle into the fork until it is fully seated.
130. Rotate the speedometer drive so that its tab is against the fork tab as shown.
131. Install the rotor cover brackets and pinch bolts. Snug, but do not tighten the pinch bolts on both forks. This is to help prevent the axle from rotating when the axle bolt is tightened.
132. Insert the axle bolt and thread it in by hand to ensure the threads are not crossed.
133. Using a torque wrench, tighten the axle bolt to 65 ft-lb. If the axle rotates, preventing the tightening of the axle bolt, insert a screwdriver into the hole that passes through the axle on the left side of the wheel, and use it to prevent the rotating of the axle.
134. Once the axle bolt is properly torqued, tighten each pinch bolt. Torque the pinch bolts to 16 ft-lb.
135. Using brake cleaner, fully clean the brake calipers, pads and rotors to remove any grease or oil residue.
136. The caliper mounting bolts need to have high-temperature brake lubricant applied.
137. Apply the lubricant to the non-threaded portion of the bolts.
138. Making sure the brake pads straddle the brake rotor, slide the caliper into place. Start the bolts in by hand, then finish using a torque wrench. The top caliper bolt is torqued to 17 ft-lb, the bottom caliper bolt is torqued to 9 ft-lb. Repeat the process with the other caliper.
139. The speedometer cable has a slotted end that rotates within the cable.
140. The speedometer drive has a flat drive that rotates with the front wheel.
141. Rotate the front wheel so that the drive rotates and properly engages the slot in the cable. Push the cable fully into the drive until the bottom screw retainer butts up against the drive.
142. Replace and snug the screw in the speedometer drive. This screw is tough to get exactly right - too tight, and the plastic screw retainer will split, causing the cable to back out of the drive when under way. Not tight enough, and the screw will back out and fall out, causing the cable to back out of the drive when under way. I used blue Loctite on this screw to encourage it to remain within the drive, without having to tighten it too much. Don't use the screw to pull the cable into place - make sure it is fully inserted before you tighten the screw.
143. Place the two brake line stabilization brackets around the brake line and link them together. Make sure you get the correct brackets on the correct sides.
144. Fit the wheel cover into place, making sure it fits under the brackets, and that the flange of the back bracket fits into the hole of the wheel cover. The back of the wheel cover also needs to fit into the back of the wheel fender. Screw the top bolt into place, but do not tighten.
145. Replace the two bottom bolts - don't forget to use their collars. Tighten these bolts, then tighten the top bolt.
146. Fit the two tabs at the front of the front fender cover into the back of the front fender, then push the rear of the front fender cover into place, inserting its post into its grommet.
Any time you work on brakes, wheels, suspension or any other safety-critical system, it is beholden upon you to TEST RIDE thoroughly at slow speed in a controlled area, to ensure that everything is working correctly.
